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venv/lib/python3.10/site-packages/scipy/fft/__init__.py

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+"""
+==============================================
+Discrete Fourier transforms (:mod:`scipy.fft`)
+==============================================
+
+.. currentmodule:: scipy.fft
+
+Fast Fourier Transforms (FFTs)
+==============================
+
+.. autosummary::
+   :toctree: generated/
+
+   fft - Fast (discrete) Fourier Transform (FFT)
+   ifft - Inverse FFT
+   fft2 - 2-D FFT
+   ifft2 - 2-D inverse FFT
+   fftn - N-D FFT
+   ifftn - N-D inverse FFT
+   rfft - FFT of strictly real-valued sequence
+   irfft - Inverse of rfft
+   rfft2 - 2-D FFT of real sequence
+   irfft2 - Inverse of rfft2
+   rfftn - N-D FFT of real sequence
+   irfftn - Inverse of rfftn
+   hfft - FFT of a Hermitian sequence (real spectrum)
+   ihfft - Inverse of hfft
+   hfft2 - 2-D FFT of a Hermitian sequence
+   ihfft2 - Inverse of hfft2
+   hfftn - N-D FFT of a Hermitian sequence
+   ihfftn - Inverse of hfftn
+
+Discrete Sin and Cosine Transforms (DST and DCT)
+================================================
+
+.. autosummary::
+   :toctree: generated/
+
+   dct - Discrete cosine transform
+   idct - Inverse discrete cosine transform
+   dctn - N-D Discrete cosine transform
+   idctn - N-D Inverse discrete cosine transform
+   dst - Discrete sine transform
+   idst - Inverse discrete sine transform
+   dstn - N-D Discrete sine transform
+   idstn - N-D Inverse discrete sine transform
+
+Fast Hankel Transforms
+======================
+
+.. autosummary::
+   :toctree: generated/
+
+   fht - Fast Hankel transform
+   ifht - Inverse of fht
+
+Helper functions
+================
+
+.. autosummary::
+   :toctree: generated/
+
+   fftshift - Shift the zero-frequency component to the center of the spectrum
+   ifftshift - The inverse of `fftshift`
+   fftfreq - Return the Discrete Fourier Transform sample frequencies
+   rfftfreq - DFT sample frequencies (for usage with rfft, irfft)
+   fhtoffset - Compute an optimal offset for the Fast Hankel Transform
+   next_fast_len - Find the optimal length to zero-pad an FFT for speed
+   set_workers - Context manager to set default number of workers
+   get_workers - Get the current default number of workers
+
+Backend control
+===============
+
+.. autosummary::
+   :toctree: generated/
+
+   set_backend - Context manager to set the backend within a fixed scope
+   skip_backend - Context manager to skip a backend within a fixed scope
+   set_global_backend - Sets the global fft backend
+   register_backend - Register a backend for permanent use
+
+"""
+
+from ._basic import (
+    fft, ifft, fft2, ifft2, fftn, ifftn,
+    rfft, irfft, rfft2, irfft2, rfftn, irfftn,
+    hfft, ihfft, hfft2, ihfft2, hfftn, ihfftn)
+from ._realtransforms import dct, idct, dst, idst, dctn, idctn, dstn, idstn
+from ._fftlog import fht, ifht, fhtoffset
+from ._helper import next_fast_len, fftfreq, rfftfreq, fftshift, ifftshift
+from ._backend import (set_backend, skip_backend, set_global_backend,
+                       register_backend)
+from ._pocketfft.helper import set_workers, get_workers
+
+__all__ = [
+    'fft', 'ifft', 'fft2', 'ifft2', 'fftn', 'ifftn',
+    'rfft', 'irfft', 'rfft2', 'irfft2', 'rfftn', 'irfftn',
+    'hfft', 'ihfft', 'hfft2', 'ihfft2', 'hfftn', 'ihfftn',
+    'fftfreq', 'rfftfreq', 'fftshift', 'ifftshift',
+    'next_fast_len',
+    'dct', 'idct', 'dst', 'idst', 'dctn', 'idctn', 'dstn', 'idstn',
+    'fht', 'ifht',
+    'fhtoffset',
+    'set_backend', 'skip_backend', 'set_global_backend', 'register_backend',
+    'get_workers', 'set_workers']
+
+
+from scipy._lib._testutils import PytestTester
+test = PytestTester(__name__)
+del PytestTester

venv/lib/python3.10/site-packages/scipy/fft/_backend.py

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+import scipy._lib.uarray as ua
+from . import _basic_backend
+from . import _realtransforms_backend
+from . import _fftlog_backend
+
+
+class _ScipyBackend:
+    """The default backend for fft calculations
+
+    Notes
+    -----
+    We use the domain ``numpy.scipy`` rather than ``scipy`` because ``uarray``
+    treats the domain as a hierarchy. This means the user can install a single
+    backend for ``numpy`` and have it implement ``numpy.scipy.fft`` as well.
+    """
+    __ua_domain__ = "numpy.scipy.fft"
+
+    @staticmethod
+    def __ua_function__(method, args, kwargs):
+
+        fn = getattr(_basic_backend, method.__name__, None)
+        if fn is None:
+            fn = getattr(_realtransforms_backend, method.__name__, None)
+        if fn is None:
+            fn = getattr(_fftlog_backend, method.__name__, None)
+        if fn is None:
+            return NotImplemented
+        return fn(*args, **kwargs)
+
+
+_named_backends = {
+    'scipy': _ScipyBackend,
+}
+
+
+def _backend_from_arg(backend):
+    """Maps strings to known backends and validates the backend"""
+
+    if isinstance(backend, str):
+        try:
+            backend = _named_backends[backend]
+        except KeyError as e:
+            raise ValueError(f'Unknown backend {backend}') from e
+
+    if backend.__ua_domain__ != 'numpy.scipy.fft':
+        raise ValueError('Backend does not implement "numpy.scipy.fft"')
+
+    return backend
+
+
+def set_global_backend(backend, coerce=False, only=False, try_last=False):
+    """Sets the global fft backend
+
+    This utility method replaces the default backend for permanent use. It
+    will be tried in the list of backends automatically, unless the
+    ``only`` flag is set on a backend. This will be the first tried
+    backend outside the :obj:`set_backend` context manager.
+
+    Parameters
+    ----------
+    backend : {object, 'scipy'}
+        The backend to use.
+        Can either be a ``str`` containing the name of a known backend
+        {'scipy'} or an object that implements the uarray protocol.
+    coerce : bool
+        Whether to coerce input types when trying this backend.
+    only : bool
+        If ``True``, no more backends will be tried if this fails.
+        Implied by ``coerce=True``.
+    try_last : bool
+        If ``True``, the global backend is tried after registered backends.
+
+    Raises
+    ------
+    ValueError: If the backend does not implement ``numpy.scipy.fft``.
+
+    Notes
+    -----
+    This will overwrite the previously set global backend, which, by default, is
+    the SciPy implementation.
+
+    Examples
+    --------
+    We can set the global fft backend:
+
+    >>> from scipy.fft import fft, set_global_backend
+    >>> set_global_backend("scipy")  # Sets global backend (default is "scipy").
+    >>> fft([1])  # Calls the global backend
+    array([1.+0.j])
+    """
+    backend = _backend_from_arg(backend)
+    ua.set_global_backend(backend, coerce=coerce, only=only, try_last=try_last)
+
+
+def register_backend(backend):
+    """
+    Register a backend for permanent use.
+
+    Registered backends have the lowest priority and will be tried after the
+    global backend.
+
+    Parameters
+    ----------
+    backend : {object, 'scipy'}
+        The backend to use.
+        Can either be a ``str`` containing the name of a known backend
+        {'scipy'} or an object that implements the uarray protocol.
+
+    Raises
+    ------
+    ValueError: If the backend does not implement ``numpy.scipy.fft``.
+
+    Examples
+    --------
+    We can register a new fft backend:
+
+    >>> from scipy.fft import fft, register_backend, set_global_backend
+    >>> class NoopBackend:  # Define an invalid Backend
+    ...     __ua_domain__ = "numpy.scipy.fft"
+    ...     def __ua_function__(self, func, args, kwargs):
+    ...          return NotImplemented
+    >>> set_global_backend(NoopBackend())  # Set the invalid backend as global
+    >>> register_backend("scipy")  # Register a new backend
+    # The registered backend is called because
+    # the global backend returns `NotImplemented`
+    >>> fft([1])
+    array([1.+0.j])
+    >>> set_global_backend("scipy")  # Restore global backend to default
+
+    """
+    backend = _backend_from_arg(backend)
+    ua.register_backend(backend)
+
+
+def set_backend(backend, coerce=False, only=False):
+    """Context manager to set the backend within a fixed scope.
+
+    Upon entering the ``with`` statement, the given backend will be added to
+    the list of available backends with the highest priority. Upon exit, the
+    backend is reset to the state before entering the scope.
+
+    Parameters
+    ----------
+    backend : {object, 'scipy'}
+        The backend to use.
+        Can either be a ``str`` containing the name of a known backend
+        {'scipy'} or an object that implements the uarray protocol.
+    coerce : bool, optional
+        Whether to allow expensive conversions for the ``x`` parameter. e.g.,
+        copying a NumPy array to the GPU for a CuPy backend. Implies ``only``.
+    only : bool, optional
+        If only is ``True`` and this backend returns ``NotImplemented``, then a
+        BackendNotImplemented error will be raised immediately. Ignoring any
+        lower priority backends.
+
+    Examples
+    --------
+    >>> import scipy.fft as fft
+    >>> with fft.set_backend('scipy', only=True):
+    ...     fft.fft([1])  # Always calls the scipy implementation
+    array([1.+0.j])
+    """
+    backend = _backend_from_arg(backend)
+    return ua.set_backend(backend, coerce=coerce, only=only)
+
+
+def skip_backend(backend):
+    """Context manager to skip a backend within a fixed scope.
+
+    Within the context of a ``with`` statement, the given backend will not be
+    called. This covers backends registered both locally and globally. Upon
+    exit, the backend will again be considered.
+
+    Parameters
+    ----------
+    backend : {object, 'scipy'}
+        The backend to skip.
+        Can either be a ``str`` containing the name of a known backend
+        {'scipy'} or an object that implements the uarray protocol.
+
+    Examples
+    --------
+    >>> import scipy.fft as fft
+    >>> fft.fft([1])  # Calls default SciPy backend
+    array([1.+0.j])
+    >>> with fft.skip_backend('scipy'):  # We explicitly skip the SciPy backend
+    ...     fft.fft([1])                 # leaving no implementation available
+    Traceback (most recent call last):
+        ...
+    BackendNotImplementedError: No selected backends had an implementation ...
+    """
+    backend = _backend_from_arg(backend)
+    return ua.skip_backend(backend)
+
+
+set_global_backend('scipy', try_last=True)

venv/lib/python3.10/site-packages/scipy/fft/_basic.py

@@ -0,0 +1,1630 @@
+from scipy._lib.uarray import generate_multimethod, Dispatchable
+import numpy as np
+
+
+def _x_replacer(args, kwargs, dispatchables):
+    """
+    uarray argument replacer to replace the transform input array (``x``)
+    """
+    if len(args) > 0:
+        return (dispatchables[0],) + args[1:], kwargs
+    kw = kwargs.copy()
+    kw['x'] = dispatchables[0]
+    return args, kw
+
+
+def _dispatch(func):
+    """
+    Function annotation that creates a uarray multimethod from the function
+    """
+    return generate_multimethod(func, _x_replacer, domain="numpy.scipy.fft")
+
+
+@_dispatch
+def fft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+        plan=None):
+    """
+    Compute the 1-D discrete Fourier Transform.
+
+    This function computes the 1-D *n*-point discrete Fourier
+    Transform (DFT) with the efficient Fast Fourier Transform (FFT)
+    algorithm [1]_.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex.
+    n : int, optional
+        Length of the transformed axis of the output.
+        If `n` is smaller than the length of the input, the input is cropped.
+        If it is larger, the input is padded with zeros. If `n` is not given,
+        the length of the input along the axis specified by `axis` is used.
+    axis : int, optional
+        Axis over which to compute the FFT. If not given, the last axis is
+        used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode. Default is "backward", meaning no normalization on
+        the forward transforms and scaling by ``1/n`` on the `ifft`.
+        "forward" instead applies the ``1/n`` factor on the forward transform.
+        For ``norm="ortho"``, both directions are scaled by ``1/sqrt(n)``.
+
+        .. versionadded:: 1.6.0
+           ``norm={"forward", "backward"}`` options were added
+
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See the notes below for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``. See below for more
+        details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+
+    Raises
+    ------
+    IndexError
+        if `axes` is larger than the last axis of `x`.
+
+    See Also
+    --------
+    ifft : The inverse of `fft`.
+    fft2 : The 2-D FFT.
+    fftn : The N-D FFT.
+    rfftn : The N-D FFT of real input.
+    fftfreq : Frequency bins for given FFT parameters.
+    next_fast_len : Size to pad input to for most efficient transforms
+
+    Notes
+    -----
+    FFT (Fast Fourier Transform) refers to a way the discrete Fourier Transform
+    (DFT) can be calculated efficiently, by using symmetries in the calculated
+    terms. The symmetry is highest when `n` is a power of 2, and the transform
+    is therefore most efficient for these sizes. For poorly factorizable sizes,
+    `scipy.fft` uses Bluestein's algorithm [2]_ and so is never worse than
+    O(`n` log `n`). Further performance improvements may be seen by zero-padding
+    the input using `next_fast_len`.
+
+    If ``x`` is a 1d array, then the `fft` is equivalent to ::
+
+        y[k] = np.sum(x * np.exp(-2j * np.pi * k * np.arange(n)/n))
+
+    The frequency term ``f=k/n`` is found at ``y[k]``. At ``y[n/2]`` we reach
+    the Nyquist frequency and wrap around to the negative-frequency terms. So,
+    for an 8-point transform, the frequencies of the result are
+    [0, 1, 2, 3, -4, -3, -2, -1]. To rearrange the fft output so that the
+    zero-frequency component is centered, like [-4, -3, -2, -1, 0, 1, 2, 3],
+    use `fftshift`.
+
+    Transforms can be done in single, double, or extended precision (long
+    double) floating point. Half precision inputs will be converted to single
+    precision and non-floating-point inputs will be converted to double
+    precision.
+
+    If the data type of ``x`` is real, a "real FFT" algorithm is automatically
+    used, which roughly halves the computation time. To increase efficiency
+    a little further, use `rfft`, which does the same calculation, but only
+    outputs half of the symmetrical spectrum. If the data are both real and
+    symmetrical, the `dct` can again double the efficiency, by generating
+    half of the spectrum from half of the signal.
+
+    When ``overwrite_x=True`` is specified, the memory referenced by ``x`` may
+    be used by the implementation in any way. This may include reusing the
+    memory for the result, but this is in no way guaranteed. You should not
+    rely on the contents of ``x`` after the transform as this may change in
+    future without warning.
+
+    The ``workers`` argument specifies the maximum number of parallel jobs to
+    split the FFT computation into. This will execute independent 1-D
+    FFTs within ``x``. So, ``x`` must be at least 2-D and the
+    non-transformed axes must be large enough to split into chunks. If ``x`` is
+    too small, fewer jobs may be used than requested.
+
+    References
+    ----------
+    .. [1] Cooley, James W., and John W. Tukey, 1965, "An algorithm for the
+           machine calculation of complex Fourier series," *Math. Comput.*
+           19: 297-301.
+    .. [2] Bluestein, L., 1970, "A linear filtering approach to the
+           computation of discrete Fourier transform". *IEEE Transactions on
+           Audio and Electroacoustics.* 18 (4): 451-455.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> scipy.fft.fft(np.exp(2j * np.pi * np.arange(8) / 8))
+    array([-2.33486982e-16+1.14423775e-17j,  8.00000000e+00-1.25557246e-15j,
+            2.33486982e-16+2.33486982e-16j,  0.00000000e+00+1.22464680e-16j,
+           -1.14423775e-17+2.33486982e-16j,  0.00000000e+00+5.20784380e-16j,
+            1.14423775e-17+1.14423775e-17j,  0.00000000e+00+1.22464680e-16j])
+
+    In this example, real input has an FFT which is Hermitian, i.e., symmetric
+    in the real part and anti-symmetric in the imaginary part:
+
+    >>> from scipy.fft import fft, fftfreq, fftshift
+    >>> import matplotlib.pyplot as plt
+    >>> t = np.arange(256)
+    >>> sp = fftshift(fft(np.sin(t)))
+    >>> freq = fftshift(fftfreq(t.shape[-1]))
+    >>> plt.plot(freq, sp.real, freq, sp.imag)
+    [<matplotlib.lines.Line2D object at 0x...>,
+     <matplotlib.lines.Line2D object at 0x...>]
+    >>> plt.show()
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ifft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    """
+    Compute the 1-D inverse discrete Fourier Transform.
+
+    This function computes the inverse of the 1-D *n*-point
+    discrete Fourier transform computed by `fft`.  In other words,
+    ``ifft(fft(x)) == x`` to within numerical accuracy.
+
+    The input should be ordered in the same way as is returned by `fft`,
+    i.e.,
+
+    * ``x[0]`` should contain the zero frequency term,
+    * ``x[1:n//2]`` should contain the positive-frequency terms,
+    * ``x[n//2 + 1:]`` should contain the negative-frequency terms, in
+      increasing order starting from the most negative frequency.
+
+    For an even number of input points, ``x[n//2]`` represents the sum of
+    the values at the positive and negative Nyquist frequencies, as the two
+    are aliased together. See `fft` for details.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex.
+    n : int, optional
+        Length of the transformed axis of the output.
+        If `n` is smaller than the length of the input, the input is cropped.
+        If it is larger, the input is padded with zeros. If `n` is not given,
+        the length of the input along the axis specified by `axis` is used.
+        See notes about padding issues.
+    axis : int, optional
+        Axis over which to compute the inverse DFT. If not given, the last
+        axis is used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+
+    Raises
+    ------
+    IndexError
+        If `axes` is larger than the last axis of `x`.
+
+    See Also
+    --------
+    fft : The 1-D (forward) FFT, of which `ifft` is the inverse.
+    ifft2 : The 2-D inverse FFT.
+    ifftn : The N-D inverse FFT.
+
+    Notes
+    -----
+    If the input parameter `n` is larger than the size of the input, the input
+    is padded by appending zeros at the end. Even though this is the common
+    approach, it might lead to surprising results. If a different padding is
+    desired, it must be performed before calling `ifft`.
+
+    If ``x`` is a 1-D array, then the `ifft` is equivalent to ::
+
+        y[k] = np.sum(x * np.exp(2j * np.pi * k * np.arange(n)/n)) / len(x)
+
+    As with `fft`, `ifft` has support for all floating point types and is
+    optimized for real input.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> scipy.fft.ifft([0, 4, 0, 0])
+    array([ 1.+0.j,  0.+1.j, -1.+0.j,  0.-1.j]) # may vary
+
+    Create and plot a band-limited signal with random phases:
+
+    >>> import matplotlib.pyplot as plt
+    >>> rng = np.random.default_rng()
+    >>> t = np.arange(400)
+    >>> n = np.zeros((400,), dtype=complex)
+    >>> n[40:60] = np.exp(1j*rng.uniform(0, 2*np.pi, (20,)))
+    >>> s = scipy.fft.ifft(n)
+    >>> plt.plot(t, s.real, 'b-', t, s.imag, 'r--')
+    [<matplotlib.lines.Line2D object at ...>, <matplotlib.lines.Line2D object at ...>]
+    >>> plt.legend(('real', 'imaginary'))
+    <matplotlib.legend.Legend object at ...>
+    >>> plt.show()
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def rfft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    """
+    Compute the 1-D discrete Fourier Transform for real input.
+
+    This function computes the 1-D *n*-point discrete Fourier
+    Transform (DFT) of a real-valued array by means of an efficient algorithm
+    called the Fast Fourier Transform (FFT).
+
+    Parameters
+    ----------
+    x : array_like
+        Input array
+    n : int, optional
+        Number of points along transformation axis in the input to use.
+        If `n` is smaller than the length of the input, the input is cropped.
+        If it is larger, the input is padded with zeros. If `n` is not given,
+        the length of the input along the axis specified by `axis` is used.
+    axis : int, optional
+        Axis over which to compute the FFT. If not given, the last axis is
+        used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+        If `n` is even, the length of the transformed axis is ``(n/2)+1``.
+        If `n` is odd, the length is ``(n+1)/2``.
+
+    Raises
+    ------
+    IndexError
+        If `axis` is larger than the last axis of `a`.
+
+    See Also
+    --------
+    irfft : The inverse of `rfft`.
+    fft : The 1-D FFT of general (complex) input.
+    fftn : The N-D FFT.
+    rfft2 : The 2-D FFT of real input.
+    rfftn : The N-D FFT of real input.
+
+    Notes
+    -----
+    When the DFT is computed for purely real input, the output is
+    Hermitian-symmetric, i.e., the negative frequency terms are just the complex
+    conjugates of the corresponding positive-frequency terms, and the
+    negative-frequency terms are therefore redundant. This function does not
+    compute the negative frequency terms, and the length of the transformed
+    axis of the output is therefore ``n//2 + 1``.
+
+    When ``X = rfft(x)`` and fs is the sampling frequency, ``X[0]`` contains
+    the zero-frequency term 0*fs, which is real due to Hermitian symmetry.
+
+    If `n` is even, ``A[-1]`` contains the term representing both positive
+    and negative Nyquist frequency (+fs/2 and -fs/2), and must also be purely
+    real. If `n` is odd, there is no term at fs/2; ``A[-1]`` contains
+    the largest positive frequency (fs/2*(n-1)/n), and is complex in the
+    general case.
+
+    If the input `a` contains an imaginary part, it is silently discarded.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> scipy.fft.fft([0, 1, 0, 0])
+    array([ 1.+0.j,  0.-1.j, -1.+0.j,  0.+1.j]) # may vary
+    >>> scipy.fft.rfft([0, 1, 0, 0])
+    array([ 1.+0.j,  0.-1.j, -1.+0.j]) # may vary
+
+    Notice how the final element of the `fft` output is the complex conjugate
+    of the second element, for real input. For `rfft`, this symmetry is
+    exploited to compute only the non-negative frequency terms.
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def irfft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Computes the inverse of `rfft`.
+
+    This function computes the inverse of the 1-D *n*-point
+    discrete Fourier Transform of real input computed by `rfft`.
+    In other words, ``irfft(rfft(x), len(x)) == x`` to within numerical
+    accuracy. (See Notes below for why ``len(a)`` is necessary here.)
+
+    The input is expected to be in the form returned by `rfft`, i.e., the
+    real zero-frequency term followed by the complex positive frequency terms
+    in order of increasing frequency. Since the discrete Fourier Transform of
+    real input is Hermitian-symmetric, the negative frequency terms are taken
+    to be the complex conjugates of the corresponding positive frequency terms.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    n : int, optional
+        Length of the transformed axis of the output.
+        For `n` output points, ``n//2+1`` input points are necessary. If the
+        input is longer than this, it is cropped. If it is shorter than this,
+        it is padded with zeros. If `n` is not given, it is taken to be
+        ``2*(m-1)``, where ``m`` is the length of the input along the axis
+        specified by `axis`.
+    axis : int, optional
+        Axis over which to compute the inverse FFT. If not given, the last
+        axis is used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+        The length of the transformed axis is `n`, or, if `n` is not given,
+        ``2*(m-1)`` where ``m`` is the length of the transformed axis of the
+        input. To get an odd number of output points, `n` must be specified.
+
+    Raises
+    ------
+    IndexError
+        If `axis` is larger than the last axis of `x`.
+
+    See Also
+    --------
+    rfft : The 1-D FFT of real input, of which `irfft` is inverse.
+    fft : The 1-D FFT.
+    irfft2 : The inverse of the 2-D FFT of real input.
+    irfftn : The inverse of the N-D FFT of real input.
+
+    Notes
+    -----
+    Returns the real valued `n`-point inverse discrete Fourier transform
+    of `x`, where `x` contains the non-negative frequency terms of a
+    Hermitian-symmetric sequence. `n` is the length of the result, not the
+    input.
+
+    If you specify an `n` such that `a` must be zero-padded or truncated, the
+    extra/removed values will be added/removed at high frequencies. One can
+    thus resample a series to `m` points via Fourier interpolation by:
+    ``a_resamp = irfft(rfft(a), m)``.
+
+    The default value of `n` assumes an even output length. By the Hermitian
+    symmetry, the last imaginary component must be 0 and so is ignored. To
+    avoid losing information, the correct length of the real input *must* be
+    given.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> scipy.fft.ifft([1, -1j, -1, 1j])
+    array([0.+0.j,  1.+0.j,  0.+0.j,  0.+0.j]) # may vary
+    >>> scipy.fft.irfft([1, -1j, -1])
+    array([0.,  1.,  0.,  0.])
+
+    Notice how the last term in the input to the ordinary `ifft` is the
+    complex conjugate of the second term, and the output has zero imaginary
+    part everywhere. When calling `irfft`, the negative frequencies are not
+    specified, and the output array is purely real.
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def hfft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    """
+    Compute the FFT of a signal that has Hermitian symmetry, i.e., a real
+    spectrum.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    n : int, optional
+        Length of the transformed axis of the output. For `n` output
+        points, ``n//2 + 1`` input points are necessary. If the input is
+        longer than this, it is cropped. If it is shorter than this, it is
+        padded with zeros. If `n` is not given, it is taken to be ``2*(m-1)``,
+        where ``m`` is the length of the input along the axis specified by
+        `axis`.
+    axis : int, optional
+        Axis over which to compute the FFT. If not given, the last
+        axis is used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See `fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+        The length of the transformed axis is `n`, or, if `n` is not given,
+        ``2*m - 2``, where ``m`` is the length of the transformed axis of
+        the input. To get an odd number of output points, `n` must be
+        specified, for instance, as ``2*m - 1`` in the typical case,
+
+    Raises
+    ------
+    IndexError
+        If `axis` is larger than the last axis of `a`.
+
+    See Also
+    --------
+    rfft : Compute the 1-D FFT for real input.
+    ihfft : The inverse of `hfft`.
+    hfftn : Compute the N-D FFT of a Hermitian signal.
+
+    Notes
+    -----
+    `hfft`/`ihfft` are a pair analogous to `rfft`/`irfft`, but for the
+    opposite case: here the signal has Hermitian symmetry in the time
+    domain and is real in the frequency domain. So, here, it's `hfft`, for
+    which you must supply the length of the result if it is to be odd.
+    * even: ``ihfft(hfft(a, 2*len(a) - 2) == a``, within roundoff error,
+    * odd: ``ihfft(hfft(a, 2*len(a) - 1) == a``, within roundoff error.
+
+    Examples
+    --------
+    >>> from scipy.fft import fft, hfft
+    >>> import numpy as np
+    >>> a = 2 * np.pi * np.arange(10) / 10
+    >>> signal = np.cos(a) + 3j * np.sin(3 * a)
+    >>> fft(signal).round(10)
+    array([ -0.+0.j,   5.+0.j,  -0.+0.j,  15.-0.j,   0.+0.j,   0.+0.j,
+            -0.+0.j, -15.-0.j,   0.+0.j,   5.+0.j])
+    >>> hfft(signal[:6]).round(10) # Input first half of signal
+    array([  0.,   5.,   0.,  15.,  -0.,   0.,   0., -15.,  -0.,   5.])
+    >>> hfft(signal, 10)  # Input entire signal and truncate
+    array([  0.,   5.,   0.,  15.,  -0.,   0.,   0., -15.,  -0.,   5.])
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ihfft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the inverse FFT of a signal that has Hermitian symmetry.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array.
+    n : int, optional
+        Length of the inverse FFT, the number of points along
+        transformation axis in the input to use.  If `n` is smaller than
+        the length of the input, the input is cropped. If it is larger,
+        the input is padded with zeros. If `n` is not given, the length of
+        the input along the axis specified by `axis` is used.
+    axis : int, optional
+        Axis over which to compute the inverse FFT. If not given, the last
+        axis is used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See `fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axis
+        indicated by `axis`, or the last one if `axis` is not specified.
+        The length of the transformed axis is ``n//2 + 1``.
+
+    See Also
+    --------
+    hfft, irfft
+
+    Notes
+    -----
+    `hfft`/`ihfft` are a pair analogous to `rfft`/`irfft`, but for the
+    opposite case: here, the signal has Hermitian symmetry in the time
+    domain and is real in the frequency domain. So, here, it's `hfft`, for
+    which you must supply the length of the result if it is to be odd:
+    * even: ``ihfft(hfft(a, 2*len(a) - 2) == a``, within roundoff error,
+    * odd: ``ihfft(hfft(a, 2*len(a) - 1) == a``, within roundoff error.
+
+    Examples
+    --------
+    >>> from scipy.fft import ifft, ihfft
+    >>> import numpy as np
+    >>> spectrum = np.array([ 15, -4, 0, -1, 0, -4])
+    >>> ifft(spectrum)
+    array([1.+0.j,  2.+0.j,  3.+0.j,  4.+0.j,  3.+0.j,  2.+0.j]) # may vary
+    >>> ihfft(spectrum)
+    array([ 1.-0.j,  2.-0.j,  3.-0.j,  4.-0.j]) # may vary
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def fftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    """
+    Compute the N-D discrete Fourier Transform.
+
+    This function computes the N-D discrete Fourier Transform over
+    any number of axes in an M-D array by means of the Fast Fourier
+    Transform (FFT).
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex.
+    s : sequence of ints, optional
+        Shape (length of each transformed axis) of the output
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.).
+        This corresponds to ``n`` for ``fft(x, n)``.
+        Along any axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` and `x`,
+        as explained in the parameters section above.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    ifftn : The inverse of `fftn`, the inverse N-D FFT.
+    fft : The 1-D FFT, with definitions and conventions used.
+    rfftn : The N-D FFT of real input.
+    fft2 : The 2-D FFT.
+    fftshift : Shifts zero-frequency terms to centre of array.
+
+    Notes
+    -----
+    The output, analogously to `fft`, contains the term for zero frequency in
+    the low-order corner of all axes, the positive frequency terms in the
+    first half of all axes, the term for the Nyquist frequency in the middle
+    of all axes and the negative frequency terms in the second half of all
+    axes, in order of decreasingly negative frequency.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.mgrid[:3, :3, :3][0]
+    >>> scipy.fft.fftn(x, axes=(1, 2))
+    array([[[ 0.+0.j,   0.+0.j,   0.+0.j], # may vary
+            [ 0.+0.j,   0.+0.j,   0.+0.j],
+            [ 0.+0.j,   0.+0.j,   0.+0.j]],
+           [[ 9.+0.j,   0.+0.j,   0.+0.j],
+            [ 0.+0.j,   0.+0.j,   0.+0.j],
+            [ 0.+0.j,   0.+0.j,   0.+0.j]],
+           [[18.+0.j,   0.+0.j,   0.+0.j],
+            [ 0.+0.j,   0.+0.j,   0.+0.j],
+            [ 0.+0.j,   0.+0.j,   0.+0.j]]])
+    >>> scipy.fft.fftn(x, (2, 2), axes=(0, 1))
+    array([[[ 2.+0.j,  2.+0.j,  2.+0.j], # may vary
+            [ 0.+0.j,  0.+0.j,  0.+0.j]],
+           [[-2.+0.j, -2.+0.j, -2.+0.j],
+            [ 0.+0.j,  0.+0.j,  0.+0.j]]])
+
+    >>> import matplotlib.pyplot as plt
+    >>> rng = np.random.default_rng()
+    >>> [X, Y] = np.meshgrid(2 * np.pi * np.arange(200) / 12,
+    ...                      2 * np.pi * np.arange(200) / 34)
+    >>> S = np.sin(X) + np.cos(Y) + rng.uniform(0, 1, X.shape)
+    >>> FS = scipy.fft.fftn(S)
+    >>> plt.imshow(np.log(np.abs(scipy.fft.fftshift(FS))**2))
+    <matplotlib.image.AxesImage object at 0x...>
+    >>> plt.show()
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ifftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the N-D inverse discrete Fourier Transform.
+
+    This function computes the inverse of the N-D discrete
+    Fourier Transform over any number of axes in an M-D array by
+    means of the Fast Fourier Transform (FFT).  In other words,
+    ``ifftn(fftn(x)) == x`` to within numerical accuracy.
+
+    The input, analogously to `ifft`, should be ordered in the same way as is
+    returned by `fftn`, i.e., it should have the term for zero frequency
+    in all axes in the low-order corner, the positive frequency terms in the
+    first half of all axes, the term for the Nyquist frequency in the middle
+    of all axes and the negative frequency terms in the second half of all
+    axes, in order of decreasingly negative frequency.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex.
+    s : sequence of ints, optional
+        Shape (length of each transformed axis) of the output
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.).
+        This corresponds to ``n`` for ``ifft(x, n)``.
+        Along any axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used. See notes for issue on `ifft` zero padding.
+    axes : sequence of ints, optional
+        Axes over which to compute the IFFT.  If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` or `x`,
+        as explained in the parameters section above.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    fftn : The forward N-D FFT, of which `ifftn` is the inverse.
+    ifft : The 1-D inverse FFT.
+    ifft2 : The 2-D inverse FFT.
+    ifftshift : Undoes `fftshift`, shifts zero-frequency terms to beginning
+        of array.
+
+    Notes
+    -----
+    Zero-padding, analogously with `ifft`, is performed by appending zeros to
+    the input along the specified dimension. Although this is the common
+    approach, it might lead to surprising results. If another form of zero
+    padding is desired, it must be performed before `ifftn` is called.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.eye(4)
+    >>> scipy.fft.ifftn(scipy.fft.fftn(x, axes=(0,)), axes=(1,))
+    array([[1.+0.j,  0.+0.j,  0.+0.j,  0.+0.j], # may vary
+           [0.+0.j,  1.+0.j,  0.+0.j,  0.+0.j],
+           [0.+0.j,  0.+0.j,  1.+0.j,  0.+0.j],
+           [0.+0.j,  0.+0.j,  0.+0.j,  1.+0.j]])
+
+
+    Create and plot an image with band-limited frequency content:
+
+    >>> import matplotlib.pyplot as plt
+    >>> rng = np.random.default_rng()
+    >>> n = np.zeros((200,200), dtype=complex)
+    >>> n[60:80, 20:40] = np.exp(1j*rng.uniform(0, 2*np.pi, (20, 20)))
+    >>> im = scipy.fft.ifftn(n).real
+    >>> plt.imshow(im)
+    <matplotlib.image.AxesImage object at 0x...>
+    >>> plt.show()
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def fft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    """
+    Compute the 2-D discrete Fourier Transform
+
+    This function computes the N-D discrete Fourier Transform
+    over any axes in an M-D array by means of the
+    Fast Fourier Transform (FFT). By default, the transform is computed over
+    the last two axes of the input array, i.e., a 2-dimensional FFT.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex
+    s : sequence of ints, optional
+        Shape (length of each transformed axis) of the output
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.).
+        This corresponds to ``n`` for ``fft(x, n)``.
+        Along each axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT. If not given, the last two axes are
+        used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or the last two axes if `axes` is not given.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length, or `axes` not given and
+        ``len(s) != 2``.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    ifft2 : The inverse 2-D FFT.
+    fft : The 1-D FFT.
+    fftn : The N-D FFT.
+    fftshift : Shifts zero-frequency terms to the center of the array.
+        For 2-D input, swaps first and third quadrants, and second
+        and fourth quadrants.
+
+    Notes
+    -----
+    `fft2` is just `fftn` with a different default for `axes`.
+
+    The output, analogously to `fft`, contains the term for zero frequency in
+    the low-order corner of the transformed axes, the positive frequency terms
+    in the first half of these axes, the term for the Nyquist frequency in the
+    middle of the axes and the negative frequency terms in the second half of
+    the axes, in order of decreasingly negative frequency.
+
+    See `fftn` for details and a plotting example, and `fft` for
+    definitions and conventions used.
+
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.mgrid[:5, :5][0]
+    >>> scipy.fft.fft2(x)
+    array([[ 50.  +0.j        ,   0.  +0.j        ,   0.  +0.j        , # may vary
+              0.  +0.j        ,   0.  +0.j        ],
+           [-12.5+17.20477401j,   0.  +0.j        ,   0.  +0.j        ,
+              0.  +0.j        ,   0.  +0.j        ],
+           [-12.5 +4.0614962j ,   0.  +0.j        ,   0.  +0.j        ,
+              0.  +0.j        ,   0.  +0.j        ],
+           [-12.5 -4.0614962j ,   0.  +0.j        ,   0.  +0.j        ,
+              0.  +0.j        ,   0.  +0.j        ],
+           [-12.5-17.20477401j,   0.  +0.j        ,   0.  +0.j        ,
+              0.  +0.j        ,   0.  +0.j        ]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ifft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the 2-D inverse discrete Fourier Transform.
+
+    This function computes the inverse of the 2-D discrete Fourier
+    Transform over any number of axes in an M-D array by means of
+    the Fast Fourier Transform (FFT). In other words, ``ifft2(fft2(x)) == x``
+    to within numerical accuracy. By default, the inverse transform is
+    computed over the last two axes of the input array.
+
+    The input, analogously to `ifft`, should be ordered in the same way as is
+    returned by `fft2`, i.e., it should have the term for zero frequency
+    in the low-order corner of the two axes, the positive frequency terms in
+    the first half of these axes, the term for the Nyquist frequency in the
+    middle of the axes and the negative frequency terms in the second half of
+    both axes, in order of decreasingly negative frequency.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, can be complex.
+    s : sequence of ints, optional
+        Shape (length of each axis) of the output (``s[0]`` refers to axis 0,
+        ``s[1]`` to axis 1, etc.). This corresponds to `n` for ``ifft(x, n)``.
+        Along each axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used.  See notes for issue on `ifft` zero padding.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT. If not given, the last two
+        axes are used.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or the last two axes if `axes` is not given.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length, or `axes` not given and
+        ``len(s) != 2``.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    fft2 : The forward 2-D FFT, of which `ifft2` is the inverse.
+    ifftn : The inverse of the N-D FFT.
+    fft : The 1-D FFT.
+    ifft : The 1-D inverse FFT.
+
+    Notes
+    -----
+    `ifft2` is just `ifftn` with a different default for `axes`.
+
+    See `ifftn` for details and a plotting example, and `fft` for
+    definition and conventions used.
+
+    Zero-padding, analogously with `ifft`, is performed by appending zeros to
+    the input along the specified dimension. Although this is the common
+    approach, it might lead to surprising results. If another form of zero
+    padding is desired, it must be performed before `ifft2` is called.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = 4 * np.eye(4)
+    >>> scipy.fft.ifft2(x)
+    array([[1.+0.j,  0.+0.j,  0.+0.j,  0.+0.j], # may vary
+           [0.+0.j,  0.+0.j,  0.+0.j,  1.+0.j],
+           [0.+0.j,  0.+0.j,  1.+0.j,  0.+0.j],
+           [0.+0.j,  1.+0.j,  0.+0.j,  0.+0.j]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def rfftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the N-D discrete Fourier Transform for real input.
+
+    This function computes the N-D discrete Fourier Transform over
+    any number of axes in an M-D real array by means of the Fast
+    Fourier Transform (FFT). By default, all axes are transformed, with the
+    real transform performed over the last axis, while the remaining
+    transforms are complex.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, taken to be real.
+    s : sequence of ints, optional
+        Shape (length along each transformed axis) to use from the input.
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.).
+        The final element of `s` corresponds to `n` for ``rfft(x, n)``, while
+        for the remaining axes, it corresponds to `n` for ``fft(x, n)``.
+        Along any axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` and `x`,
+        as explained in the parameters section above.
+        The length of the last axis transformed will be ``s[-1]//2+1``,
+        while the remaining transformed axes will have lengths according to
+        `s`, or unchanged from the input.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    irfftn : The inverse of `rfftn`, i.e., the inverse of the N-D FFT
+         of real input.
+    fft : The 1-D FFT, with definitions and conventions used.
+    rfft : The 1-D FFT of real input.
+    fftn : The N-D FFT.
+    rfft2 : The 2-D FFT of real input.
+
+    Notes
+    -----
+    The transform for real input is performed over the last transformation
+    axis, as by `rfft`, then the transform over the remaining axes is
+    performed as by `fftn`. The order of the output is as for `rfft` for the
+    final transformation axis, and as for `fftn` for the remaining
+    transformation axes.
+
+    See `fft` for details, definitions and conventions used.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.ones((2, 2, 2))
+    >>> scipy.fft.rfftn(x)
+    array([[[8.+0.j,  0.+0.j], # may vary
+            [0.+0.j,  0.+0.j]],
+           [[0.+0.j,  0.+0.j],
+            [0.+0.j,  0.+0.j]]])
+
+    >>> scipy.fft.rfftn(x, axes=(2, 0))
+    array([[[4.+0.j,  0.+0.j], # may vary
+            [4.+0.j,  0.+0.j]],
+           [[0.+0.j,  0.+0.j],
+            [0.+0.j,  0.+0.j]]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def rfft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the 2-D FFT of a real array.
+
+    Parameters
+    ----------
+    x : array
+        Input array, taken to be real.
+    s : sequence of ints, optional
+        Shape of the FFT.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The result of the real 2-D FFT.
+
+    See Also
+    --------
+    irfft2 : The inverse of the 2-D FFT of real input.
+    rfft : The 1-D FFT of real input.
+    rfftn : Compute the N-D discrete Fourier Transform for real
+            input.
+
+    Notes
+    -----
+    This is really just `rfftn` with different default behavior.
+    For more details see `rfftn`.
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def irfftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+           plan=None):
+    """
+    Computes the inverse of `rfftn`
+
+    This function computes the inverse of the N-D discrete
+    Fourier Transform for real input over any number of axes in an
+    M-D array by means of the Fast Fourier Transform (FFT). In
+    other words, ``irfftn(rfftn(x), x.shape) == x`` to within numerical
+    accuracy. (The ``a.shape`` is necessary like ``len(a)`` is for `irfft`,
+    and for the same reason.)
+
+    The input should be ordered in the same way as is returned by `rfftn`,
+    i.e., as for `irfft` for the final transformation axis, and as for `ifftn`
+    along all the other axes.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array.
+    s : sequence of ints, optional
+        Shape (length of each transformed axis) of the output
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). `s` is also the
+        number of input points used along this axis, except for the last axis,
+        where ``s[-1]//2+1`` points of the input are used.
+        Along any axis, if the shape indicated by `s` is smaller than that of
+        the input, the input is cropped. If it is larger, the input is padded
+        with zeros. If `s` is not given, the shape of the input along the axes
+        specified by axes is used. Except for the last axis which is taken to be
+        ``2*(m-1)``, where ``m`` is the length of the input along that axis.
+    axes : sequence of ints, optional
+        Axes over which to compute the inverse FFT. If not given, the last
+        `len(s)` axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` or `x`,
+        as explained in the parameters section above.
+        The length of each transformed axis is as given by the corresponding
+        element of `s`, or the length of the input in every axis except for the
+        last one if `s` is not given. In the final transformed axis the length
+        of the output when `s` is not given is ``2*(m-1)``, where ``m`` is the
+        length of the final transformed axis of the input. To get an odd
+        number of output points in the final axis, `s` must be specified.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    rfftn : The forward N-D FFT of real input,
+            of which `ifftn` is the inverse.
+    fft : The 1-D FFT, with definitions and conventions used.
+    irfft : The inverse of the 1-D FFT of real input.
+    irfft2 : The inverse of the 2-D FFT of real input.
+
+    Notes
+    -----
+    See `fft` for definitions and conventions used.
+
+    See `rfft` for definitions and conventions used for real input.
+
+    The default value of `s` assumes an even output length in the final
+    transformation axis. When performing the final complex to real
+    transformation, the Hermitian symmetry requires that the last imaginary
+    component along that axis must be 0 and so it is ignored. To avoid losing
+    information, the correct length of the real input *must* be given.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.zeros((3, 2, 2))
+    >>> x[0, 0, 0] = 3 * 2 * 2
+    >>> scipy.fft.irfftn(x)
+    array([[[1.,  1.],
+            [1.,  1.]],
+           [[1.,  1.],
+            [1.,  1.]],
+           [[1.,  1.],
+            [1.,  1.]]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def irfft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+           plan=None):
+    """
+    Computes the inverse of `rfft2`
+
+    Parameters
+    ----------
+    x : array_like
+        The input array
+    s : sequence of ints, optional
+        Shape of the real output to the inverse FFT.
+    axes : sequence of ints, optional
+        The axes over which to compute the inverse fft.
+        Default is the last two axes.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The result of the inverse real 2-D FFT.
+
+    See Also
+    --------
+    rfft2 : The 2-D FFT of real input.
+    irfft : The inverse of the 1-D FFT of real input.
+    irfftn : The inverse of the N-D FFT of real input.
+
+    Notes
+    -----
+    This is really `irfftn` with different defaults.
+    For more details see `irfftn`.
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def hfftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the N-D FFT of Hermitian symmetric complex input, i.e., a
+    signal with a real spectrum.
+
+    This function computes the N-D discrete Fourier Transform for a
+    Hermitian symmetric complex input over any number of axes in an
+    M-D array by means of the Fast Fourier Transform (FFT). In other
+    words, ``ihfftn(hfftn(x, s)) == x`` to within numerical accuracy. (``s``
+    here is ``x.shape`` with ``s[-1] = x.shape[-1] * 2 - 1``, this is necessary
+    for the same reason ``x.shape`` would be necessary for `irfft`.)
+
+    Parameters
+    ----------
+    x : array_like
+        Input array.
+    s : sequence of ints, optional
+        Shape (length of each transformed axis) of the output
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). `s` is also the
+        number of input points used along this axis, except for the last axis,
+        where ``s[-1]//2+1`` points of the input are used.
+        Along any axis, if the shape indicated by `s` is smaller than that of
+        the input, the input is cropped. If it is larger, the input is padded
+        with zeros. If `s` is not given, the shape of the input along the axes
+        specified by axes is used. Except for the last axis which is taken to be
+        ``2*(m-1)`` where ``m`` is the length of the input along that axis.
+    axes : sequence of ints, optional
+        Axes over which to compute the inverse FFT. If not given, the last
+        `len(s)` axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` or `x`,
+        as explained in the parameters section above.
+        The length of each transformed axis is as given by the corresponding
+        element of `s`, or the length of the input in every axis except for the
+        last one if `s` is not given.  In the final transformed axis the length
+        of the output when `s` is not given is ``2*(m-1)`` where ``m`` is the
+        length of the final transformed axis of the input.  To get an odd
+        number of output points in the final axis, `s` must be specified.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    ihfftn : The inverse N-D FFT with real spectrum. Inverse of `hfftn`.
+    fft : The 1-D FFT, with definitions and conventions used.
+    rfft : Forward FFT of real input.
+
+    Notes
+    -----
+    For a 1-D signal ``x`` to have a real spectrum, it must satisfy
+    the Hermitian property::
+
+        x[i] == np.conj(x[-i]) for all i
+
+    This generalizes into higher dimensions by reflecting over each axis in
+    turn::
+
+        x[i, j, k, ...] == np.conj(x[-i, -j, -k, ...]) for all i, j, k, ...
+
+    This should not be confused with a Hermitian matrix, for which the
+    transpose is its own conjugate::
+
+        x[i, j] == np.conj(x[j, i]) for all i, j
+
+
+    The default value of `s` assumes an even output length in the final
+    transformation axis. When performing the final complex to real
+    transformation, the Hermitian symmetry requires that the last imaginary
+    component along that axis must be 0 and so it is ignored. To avoid losing
+    information, the correct length of the real input *must* be given.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.ones((3, 2, 2))
+    >>> scipy.fft.hfftn(x)
+    array([[[12.,  0.],
+            [ 0.,  0.]],
+           [[ 0.,  0.],
+            [ 0.,  0.]],
+           [[ 0.,  0.],
+            [ 0.,  0.]]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def hfft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+          plan=None):
+    """
+    Compute the 2-D FFT of a Hermitian complex array.
+
+    Parameters
+    ----------
+    x : array
+        Input array, taken to be Hermitian complex.
+    s : sequence of ints, optional
+        Shape of the real output.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See `fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The real result of the 2-D Hermitian complex real FFT.
+
+    See Also
+    --------
+    hfftn : Compute the N-D discrete Fourier Transform for Hermitian
+            complex input.
+
+    Notes
+    -----
+    This is really just `hfftn` with different default behavior.
+    For more details see `hfftn`.
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ihfftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *,
+           plan=None):
+    """
+    Compute the N-D inverse discrete Fourier Transform for a real
+    spectrum.
+
+    This function computes the N-D inverse discrete Fourier Transform
+    over any number of axes in an M-D real array by means of the Fast
+    Fourier Transform (FFT). By default, all axes are transformed, with the
+    real transform performed over the last axis, while the remaining transforms
+    are complex.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array, taken to be real.
+    s : sequence of ints, optional
+        Shape (length along each transformed axis) to use from the input.
+        (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.).
+        Along any axis, if the given shape is smaller than that of the input,
+        the input is cropped. If it is larger, the input is padded with zeros.
+        if `s` is not given, the shape of the input along the axes specified
+        by `axes` is used.
+    axes : sequence of ints, optional
+        Axes over which to compute the FFT. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : complex ndarray
+        The truncated or zero-padded input, transformed along the axes
+        indicated by `axes`, or by a combination of `s` and `x`,
+        as explained in the parameters section above.
+        The length of the last axis transformed will be ``s[-1]//2+1``,
+        while the remaining transformed axes will have lengths according to
+        `s`, or unchanged from the input.
+
+    Raises
+    ------
+    ValueError
+        If `s` and `axes` have different length.
+    IndexError
+        If an element of `axes` is larger than the number of axes of `x`.
+
+    See Also
+    --------
+    hfftn : The forward N-D FFT of Hermitian input.
+    hfft : The 1-D FFT of Hermitian input.
+    fft : The 1-D FFT, with definitions and conventions used.
+    fftn : The N-D FFT.
+    hfft2 : The 2-D FFT of Hermitian input.
+
+    Notes
+    -----
+    The transform for real input is performed over the last transformation
+    axis, as by `ihfft`, then the transform over the remaining axes is
+    performed as by `ifftn`. The order of the output is the positive part of
+    the Hermitian output signal, in the same format as `rfft`.
+
+    Examples
+    --------
+    >>> import scipy.fft
+    >>> import numpy as np
+    >>> x = np.ones((2, 2, 2))
+    >>> scipy.fft.ihfftn(x)
+    array([[[1.+0.j,  0.+0.j], # may vary
+            [0.+0.j,  0.+0.j]],
+           [[0.+0.j,  0.+0.j],
+            [0.+0.j,  0.+0.j]]])
+    >>> scipy.fft.ihfftn(x, axes=(2, 0))
+    array([[[1.+0.j,  0.+0.j], # may vary
+            [1.+0.j,  0.+0.j]],
+           [[0.+0.j,  0.+0.j],
+            [0.+0.j,  0.+0.j]]])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def ihfft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *,
+           plan=None):
+    """
+    Compute the 2-D inverse FFT of a real spectrum.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array
+    s : sequence of ints, optional
+        Shape of the real input to the inverse FFT.
+    axes : sequence of ints, optional
+        The axes over which to compute the inverse fft.
+        Default is the last two axes.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see `fft`). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+        See :func:`fft` for more details.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    plan : object, optional
+        This argument is reserved for passing in a precomputed plan provided
+        by downstream FFT vendors. It is currently not used in SciPy.
+
+        .. versionadded:: 1.5.0
+
+    Returns
+    -------
+    out : ndarray
+        The result of the inverse real 2-D FFT.
+
+    See Also
+    --------
+    ihfftn : Compute the inverse of the N-D FFT of Hermitian input.
+
+    Notes
+    -----
+    This is really `ihfftn` with different defaults.
+    For more details see `ihfftn`.
+
+    """
+    return (Dispatchable(x, np.ndarray),)

venv/lib/python3.10/site-packages/scipy/fft/_basic_backend.py

@@ -0,0 +1,176 @@
+from scipy._lib._array_api import (
+    array_namespace, is_numpy, xp_unsupported_param_msg, is_complex
+)
+from . import _pocketfft
+import numpy as np
+
+
+def _validate_fft_args(workers, plan, norm):
+    if workers is not None:
+        raise ValueError(xp_unsupported_param_msg("workers"))
+    if plan is not None:
+        raise ValueError(xp_unsupported_param_msg("plan"))
+    if norm is None:
+        norm = 'backward'
+    return norm
+
+
+# pocketfft is used whenever SCIPY_ARRAY_API is not set,
+# or x is a NumPy array or array-like.
+# When SCIPY_ARRAY_API is set, we try to use xp.fft for CuPy arrays,
+# PyTorch arrays and other array API standard supporting objects.
+# If xp.fft does not exist, we attempt to convert to np and back to use pocketfft.
+
+def _execute_1D(func_str, pocketfft_func, x, n, axis, norm, overwrite_x, workers, plan):
+    xp = array_namespace(x)
+
+    if is_numpy(xp):
+        return pocketfft_func(x, n=n, axis=axis, norm=norm,
+                              overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+    norm = _validate_fft_args(workers, plan, norm)
+    if hasattr(xp, 'fft'):
+        xp_func = getattr(xp.fft, func_str)
+        return xp_func(x, n=n, axis=axis, norm=norm)
+
+    x = np.asarray(x)
+    y = pocketfft_func(x, n=n, axis=axis, norm=norm)
+    return xp.asarray(y)
+
+
+def _execute_nD(func_str, pocketfft_func, x, s, axes, norm, overwrite_x, workers, plan):
+    xp = array_namespace(x)
+    
+    if is_numpy(xp):
+        return pocketfft_func(x, s=s, axes=axes, norm=norm,
+                              overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+    norm = _validate_fft_args(workers, plan, norm)
+    if hasattr(xp, 'fft'):
+        xp_func = getattr(xp.fft, func_str)
+        return xp_func(x, s=s, axes=axes, norm=norm)
+
+    x = np.asarray(x)
+    y = pocketfft_func(x, s=s, axes=axes, norm=norm)
+    return xp.asarray(y)
+
+
+def fft(x, n=None, axis=-1, norm=None,
+        overwrite_x=False, workers=None, *, plan=None):
+    return _execute_1D('fft', _pocketfft.fft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def ifft(x, n=None, axis=-1, norm=None, overwrite_x=False, workers=None, *,
+         plan=None):
+    return _execute_1D('ifft', _pocketfft.ifft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def rfft(x, n=None, axis=-1, norm=None,
+         overwrite_x=False, workers=None, *, plan=None):
+    return _execute_1D('rfft', _pocketfft.rfft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def irfft(x, n=None, axis=-1, norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return _execute_1D('irfft', _pocketfft.irfft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def hfft(x, n=None, axis=-1, norm=None,
+         overwrite_x=False, workers=None, *, plan=None):
+    return _execute_1D('hfft', _pocketfft.hfft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def ihfft(x, n=None, axis=-1, norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return _execute_1D('ihfft', _pocketfft.ihfft, x, n=n, axis=axis, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def fftn(x, s=None, axes=None, norm=None,
+         overwrite_x=False, workers=None, *, plan=None):
+    return _execute_nD('fftn', _pocketfft.fftn, x, s=s, axes=axes, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+
+def ifftn(x, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return _execute_nD('ifftn', _pocketfft.ifftn, x, s=s, axes=axes, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def fft2(x, s=None, axes=(-2, -1), norm=None,
+         overwrite_x=False, workers=None, *, plan=None):
+    return fftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+
+
+def ifft2(x, s=None, axes=(-2, -1), norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return ifftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+
+
+def rfftn(x, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return _execute_nD('rfftn', _pocketfft.rfftn, x, s=s, axes=axes, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def rfft2(x, s=None, axes=(-2, -1), norm=None,
+         overwrite_x=False, workers=None, *, plan=None):
+    return rfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+
+
+def irfftn(x, s=None, axes=None, norm=None,
+           overwrite_x=False, workers=None, *, plan=None):
+    return _execute_nD('irfftn', _pocketfft.irfftn, x, s=s, axes=axes, norm=norm,
+                       overwrite_x=overwrite_x, workers=workers, plan=plan)
+
+
+def irfft2(x, s=None, axes=(-2, -1), norm=None,
+           overwrite_x=False, workers=None, *, plan=None):
+    return irfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+
+
+def _swap_direction(norm):
+    if norm in (None, 'backward'):
+        norm = 'forward'
+    elif norm == 'forward':
+        norm = 'backward'
+    elif norm != 'ortho':
+        raise ValueError('Invalid norm value %s; should be "backward", '
+                         '"ortho", or "forward".' % norm)
+    return norm
+
+
+def hfftn(x, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    xp = array_namespace(x)
+    if is_numpy(xp):
+        return _pocketfft.hfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+    if is_complex(x, xp):
+        x = xp.conj(x)
+    return irfftn(x, s, axes, _swap_direction(norm),
+                  overwrite_x, workers, plan=plan)
+
+
+def hfft2(x, s=None, axes=(-2, -1), norm=None,
+          overwrite_x=False, workers=None, *, plan=None):
+    return hfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+
+
+def ihfftn(x, s=None, axes=None, norm=None,
+           overwrite_x=False, workers=None, *, plan=None):
+    xp = array_namespace(x)
+    if is_numpy(xp):
+        return _pocketfft.ihfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)
+    return xp.conj(rfftn(x, s, axes, _swap_direction(norm),
+                         overwrite_x, workers, plan=plan))
+
+def ihfft2(x, s=None, axes=(-2, -1), norm=None,
+           overwrite_x=False, workers=None, *, plan=None):
+    return ihfftn(x, s, axes, norm, overwrite_x, workers, plan=plan)

venv/lib/python3.10/site-packages/scipy/fft/_debug_backends.py

@@ -0,0 +1,22 @@
+import numpy as np
+
+class NumPyBackend:
+    """Backend that uses numpy.fft"""
+    __ua_domain__ = "numpy.scipy.fft"
+
+    @staticmethod
+    def __ua_function__(method, args, kwargs):
+        kwargs.pop("overwrite_x", None)
+
+        fn = getattr(np.fft, method.__name__, None)
+        return (NotImplemented if fn is None
+                else fn(*args, **kwargs))
+
+
+class EchoBackend:
+    """Backend that just prints the __ua_function__ arguments"""
+    __ua_domain__ = "numpy.scipy.fft"
+
+    @staticmethod
+    def __ua_function__(method, args, kwargs):
+        print(method, args, kwargs, sep='\n')

venv/lib/python3.10/site-packages/scipy/fft/_fftlog.py

@@ -0,0 +1,223 @@
+"""Fast Hankel transforms using the FFTLog algorithm.
+
+The implementation closely follows the Fortran code of Hamilton (2000).
+
+added: 14/11/2020 Nicolas Tessore <[email protected]>
+"""
+
+from ._basic import _dispatch
+from scipy._lib.uarray import Dispatchable
+from ._fftlog_backend import fhtoffset
+import numpy as np
+
+__all__ = ['fht', 'ifht', 'fhtoffset']
+
+
+@_dispatch
+def fht(a, dln, mu, offset=0.0, bias=0.0):
+    r'''Compute the fast Hankel transform.
+
+    Computes the discrete Hankel transform of a logarithmically spaced periodic
+    sequence using the FFTLog algorithm [1]_, [2]_.
+
+    Parameters
+    ----------
+    a : array_like (..., n)
+        Real periodic input array, uniformly logarithmically spaced.  For
+        multidimensional input, the transform is performed over the last axis.
+    dln : float
+        Uniform logarithmic spacing of the input array.
+    mu : float
+        Order of the Hankel transform, any positive or negative real number.
+    offset : float, optional
+        Offset of the uniform logarithmic spacing of the output array.
+    bias : float, optional
+        Exponent of power law bias, any positive or negative real number.
+
+    Returns
+    -------
+    A : array_like (..., n)
+        The transformed output array, which is real, periodic, uniformly
+        logarithmically spaced, and of the same shape as the input array.
+
+    See Also
+    --------
+    ifht : The inverse of `fht`.
+    fhtoffset : Return an optimal offset for `fht`.
+
+    Notes
+    -----
+    This function computes a discrete version of the Hankel transform
+
+    .. math::
+
+        A(k) = \int_{0}^{\infty} \! a(r) \, J_\mu(kr) \, k \, dr \;,
+
+    where :math:`J_\mu` is the Bessel function of order :math:`\mu`.  The index
+    :math:`\mu` may be any real number, positive or negative.  Note that the
+    numerical Hankel transform uses an integrand of :math:`k \, dr`, while the
+    mathematical Hankel transform is commonly defined using :math:`r \, dr`.
+
+    The input array `a` is a periodic sequence of length :math:`n`, uniformly
+    logarithmically spaced with spacing `dln`,
+
+    .. math::
+
+        a_j = a(r_j) \;, \quad
+        r_j = r_c \exp[(j-j_c) \, \mathtt{dln}]
+
+    centred about the point :math:`r_c`.  Note that the central index
+    :math:`j_c = (n-1)/2` is half-integral if :math:`n` is even, so that
+    :math:`r_c` falls between two input elements.  Similarly, the output
+    array `A` is a periodic sequence of length :math:`n`, also uniformly
+    logarithmically spaced with spacing `dln`
+
+    .. math::
+
+       A_j = A(k_j) \;, \quad
+       k_j = k_c \exp[(j-j_c) \, \mathtt{dln}]
+
+    centred about the point :math:`k_c`.
+
+    The centre points :math:`r_c` and :math:`k_c` of the periodic intervals may
+    be chosen arbitrarily, but it would be usual to choose the product
+    :math:`k_c r_c = k_j r_{n-1-j} = k_{n-1-j} r_j` to be unity.  This can be
+    changed using the `offset` parameter, which controls the logarithmic offset
+    :math:`\log(k_c) = \mathtt{offset} - \log(r_c)` of the output array.
+    Choosing an optimal value for `offset` may reduce ringing of the discrete
+    Hankel transform.
+
+    If the `bias` parameter is nonzero, this function computes a discrete
+    version of the biased Hankel transform
+
+    .. math::
+
+        A(k) = \int_{0}^{\infty} \! a_q(r) \, (kr)^q \, J_\mu(kr) \, k \, dr
+
+    where :math:`q` is the value of `bias`, and a power law bias
+    :math:`a_q(r) = a(r) \, (kr)^{-q}` is applied to the input sequence.
+    Biasing the transform can help approximate the continuous transform of
+    :math:`a(r)` if there is a value :math:`q` such that :math:`a_q(r)` is
+    close to a periodic sequence, in which case the resulting :math:`A(k)` will
+    be close to the continuous transform.
+
+    References
+    ----------
+    .. [1] Talman J. D., 1978, J. Comp. Phys., 29, 35
+    .. [2] Hamilton A. J. S., 2000, MNRAS, 312, 257 (astro-ph/9905191)
+
+    Examples
+    --------
+
+    This example is the adapted version of ``fftlogtest.f`` which is provided
+    in [2]_. It evaluates the integral
+
+    .. math::
+
+        \int^\infty_0 r^{\mu+1} \exp(-r^2/2) J_\mu(k, r) k dr
+        = k^{\mu+1} \exp(-k^2/2) .
+
+    >>> import numpy as np
+    >>> from scipy import fft
+    >>> import matplotlib.pyplot as plt
+
+    Parameters for the transform.
+
+    >>> mu = 0.0                     # Order mu of Bessel function
+    >>> r = np.logspace(-7, 1, 128)  # Input evaluation points
+    >>> dln = np.log(r[1]/r[0])      # Step size
+    >>> offset = fft.fhtoffset(dln, initial=-6*np.log(10), mu=mu)
+    >>> k = np.exp(offset)/r[::-1]   # Output evaluation points
+
+    Define the analytical function.
+
+    >>> def f(x, mu):
+    ...     """Analytical function: x^(mu+1) exp(-x^2/2)."""
+    ...     return x**(mu + 1)*np.exp(-x**2/2)
+
+    Evaluate the function at ``r`` and compute the corresponding values at
+    ``k`` using FFTLog.
+
+    >>> a_r = f(r, mu)
+    >>> fht = fft.fht(a_r, dln, mu=mu, offset=offset)
+
+    For this example we can actually compute the analytical response (which in
+    this case is the same as the input function) for comparison and compute the
+    relative error.
+
+    >>> a_k = f(k, mu)
+    >>> rel_err = abs((fht-a_k)/a_k)
+
+    Plot the result.
+
+    >>> figargs = {'sharex': True, 'sharey': True, 'constrained_layout': True}
+    >>> fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(10, 4), **figargs)
+    >>> ax1.set_title(r'$r^{\mu+1}\ \exp(-r^2/2)$')
+    >>> ax1.loglog(r, a_r, 'k', lw=2)
+    >>> ax1.set_xlabel('r')
+    >>> ax2.set_title(r'$k^{\mu+1} \exp(-k^2/2)$')
+    >>> ax2.loglog(k, a_k, 'k', lw=2, label='Analytical')
+    >>> ax2.loglog(k, fht, 'C3--', lw=2, label='FFTLog')
+    >>> ax2.set_xlabel('k')
+    >>> ax2.legend(loc=3, framealpha=1)
+    >>> ax2.set_ylim([1e-10, 1e1])
+    >>> ax2b = ax2.twinx()
+    >>> ax2b.loglog(k, rel_err, 'C0', label='Rel. Error (-)')
+    >>> ax2b.set_ylabel('Rel. Error (-)', color='C0')
+    >>> ax2b.tick_params(axis='y', labelcolor='C0')
+    >>> ax2b.legend(loc=4, framealpha=1)
+    >>> ax2b.set_ylim([1e-9, 1e-3])
+    >>> plt.show()
+
+    '''
+    return (Dispatchable(a, np.ndarray),)
+
+
+@_dispatch
+def ifht(A, dln, mu, offset=0.0, bias=0.0):
+    r"""Compute the inverse fast Hankel transform.
+
+    Computes the discrete inverse Hankel transform of a logarithmically spaced
+    periodic sequence. This is the inverse operation to `fht`.
+
+    Parameters
+    ----------
+    A : array_like (..., n)
+        Real periodic input array, uniformly logarithmically spaced.  For
+        multidimensional input, the transform is performed over the last axis.
+    dln : float
+        Uniform logarithmic spacing of the input array.
+    mu : float
+        Order of the Hankel transform, any positive or negative real number.
+    offset : float, optional
+        Offset of the uniform logarithmic spacing of the output array.
+    bias : float, optional
+        Exponent of power law bias, any positive or negative real number.
+
+    Returns
+    -------
+    a : array_like (..., n)
+        The transformed output array, which is real, periodic, uniformly
+        logarithmically spaced, and of the same shape as the input array.
+
+    See Also
+    --------
+    fht : Definition of the fast Hankel transform.
+    fhtoffset : Return an optimal offset for `ifht`.
+
+    Notes
+    -----
+    This function computes a discrete version of the Hankel transform
+
+    .. math::
+
+        a(r) = \int_{0}^{\infty} \! A(k) \, J_\mu(kr) \, r \, dk \;,
+
+    where :math:`J_\mu` is the Bessel function of order :math:`\mu`.  The index
+    :math:`\mu` may be any real number, positive or negative. Note that the
+    numerical inverse Hankel transform uses an integrand of :math:`r \, dk`, while the
+    mathematical inverse Hankel transform is commonly defined using :math:`k \, dk`.
+
+    See `fht` for further details.
+    """
+    return (Dispatchable(A, np.ndarray),)

venv/lib/python3.10/site-packages/scipy/fft/_fftlog_backend.py

@@ -0,0 +1,197 @@
+import numpy as np
+from warnings import warn
+from ._basic import rfft, irfft
+from ..special import loggamma, poch
+
+from scipy._lib._array_api import array_namespace, copy
+
+__all__ = ['fht', 'ifht', 'fhtoffset']
+
+# constants
+LN_2 = np.log(2)
+
+
+def fht(a, dln, mu, offset=0.0, bias=0.0):
+    xp = array_namespace(a)
+
+    # size of transform
+    n = a.shape[-1]
+
+    # bias input array
+    if bias != 0:
+        # a_q(r) = a(r) (r/r_c)^{-q}
+        j_c = (n-1)/2
+        j = xp.arange(n, dtype=xp.float64)
+        a = a * xp.exp(-bias*(j - j_c)*dln)
+
+    # compute FHT coefficients
+    u = xp.asarray(fhtcoeff(n, dln, mu, offset=offset, bias=bias))
+
+    # transform
+    A = _fhtq(a, u, xp=xp)
+
+    # bias output array
+    if bias != 0:
+        # A(k) = A_q(k) (k/k_c)^{-q} (k_c r_c)^{-q}
+        A *= xp.exp(-bias*((j - j_c)*dln + offset))
+
+    return A
+
+
+def ifht(A, dln, mu, offset=0.0, bias=0.0):
+    xp = array_namespace(A)
+
+    # size of transform
+    n = A.shape[-1]
+
+    # bias input array
+    if bias != 0:
+        # A_q(k) = A(k) (k/k_c)^{q} (k_c r_c)^{q}
+        j_c = (n-1)/2
+        j = xp.arange(n, dtype=xp.float64)
+        A = A * xp.exp(bias*((j - j_c)*dln + offset))
+
+    # compute FHT coefficients
+    u = xp.asarray(fhtcoeff(n, dln, mu, offset=offset, bias=bias, inverse=True))
+
+    # transform
+    a = _fhtq(A, u, inverse=True, xp=xp)
+
+    # bias output array
+    if bias != 0:
+        # a(r) = a_q(r) (r/r_c)^{q}
+        a /= xp.exp(-bias*(j - j_c)*dln)
+
+    return a
+
+
+def fhtcoeff(n, dln, mu, offset=0.0, bias=0.0, inverse=False):
+    """Compute the coefficient array for a fast Hankel transform."""
+    lnkr, q = offset, bias
+
+    # Hankel transform coefficients
+    # u_m = (kr)^{-i 2m pi/(n dlnr)} U_mu(q + i 2m pi/(n dlnr))
+    # with U_mu(x) = 2^x Gamma((mu+1+x)/2)/Gamma((mu+1-x)/2)
+    xp = (mu+1+q)/2
+    xm = (mu+1-q)/2
+    y = np.linspace(0, np.pi*(n//2)/(n*dln), n//2+1)
+    u = np.empty(n//2+1, dtype=complex)
+    v = np.empty(n//2+1, dtype=complex)
+    u.imag[:] = y
+    u.real[:] = xm
+    loggamma(u, out=v)
+    u.real[:] = xp
+    loggamma(u, out=u)
+    y *= 2*(LN_2 - lnkr)
+    u.real -= v.real
+    u.real += LN_2*q
+    u.imag += v.imag
+    u.imag += y
+    np.exp(u, out=u)
+
+    # fix last coefficient to be real
+    u.imag[-1] = 0
+
+    # deal with special cases
+    if not np.isfinite(u[0]):
+        # write u_0 = 2^q Gamma(xp)/Gamma(xm) = 2^q poch(xm, xp-xm)
+        # poch() handles special cases for negative integers correctly
+        u[0] = 2**q * poch(xm, xp-xm)
+        # the coefficient may be inf or 0, meaning the transform or the
+        # inverse transform, respectively, is singular
+
+    # check for singular transform or singular inverse transform
+    if np.isinf(u[0]) and not inverse:
+        warn('singular transform; consider changing the bias', stacklevel=3)
+        # fix coefficient to obtain (potentially correct) transform anyway
+        u = copy(u)
+        u[0] = 0
+    elif u[0] == 0 and inverse:
+        warn('singular inverse transform; consider changing the bias', stacklevel=3)
+        # fix coefficient to obtain (potentially correct) inverse anyway
+        u = copy(u)
+        u[0] = np.inf
+
+    return u
+
+
+def fhtoffset(dln, mu, initial=0.0, bias=0.0):
+    """Return optimal offset for a fast Hankel transform.
+
+    Returns an offset close to `initial` that fulfils the low-ringing
+    condition of [1]_ for the fast Hankel transform `fht` with logarithmic
+    spacing `dln`, order `mu` and bias `bias`.
+
+    Parameters
+    ----------
+    dln : float
+        Uniform logarithmic spacing of the transform.
+    mu : float
+        Order of the Hankel transform, any positive or negative real number.
+    initial : float, optional
+        Initial value for the offset. Returns the closest value that fulfils
+        the low-ringing condition.
+    bias : float, optional
+        Exponent of power law bias, any positive or negative real number.
+
+    Returns
+    -------
+    offset : float
+        Optimal offset of the uniform logarithmic spacing of the transform that
+        fulfils a low-ringing condition.
+
+    Examples
+    --------
+    >>> from scipy.fft import fhtoffset
+    >>> dln = 0.1
+    >>> mu = 2.0
+    >>> initial = 0.5
+    >>> bias = 0.0
+    >>> offset = fhtoffset(dln, mu, initial, bias)
+    >>> offset
+    0.5454581477676637
+
+    See Also
+    --------
+    fht : Definition of the fast Hankel transform.
+
+    References
+    ----------
+    .. [1] Hamilton A. J. S., 2000, MNRAS, 312, 257 (astro-ph/9905191)
+
+    """
+
+    lnkr, q = initial, bias
+
+    xp = (mu+1+q)/2
+    xm = (mu+1-q)/2
+    y = np.pi/(2*dln)
+    zp = loggamma(xp + 1j*y)
+    zm = loggamma(xm + 1j*y)
+    arg = (LN_2 - lnkr)/dln + (zp.imag + zm.imag)/np.pi
+    return lnkr + (arg - np.round(arg))*dln
+
+
+def _fhtq(a, u, inverse=False, *, xp=None):
+    """Compute the biased fast Hankel transform.
+
+    This is the basic FFTLog routine.
+    """
+    if xp is None:
+        xp = np
+
+    # size of transform
+    n = a.shape[-1]
+
+    # biased fast Hankel transform via real FFT
+    A = rfft(a, axis=-1)
+    if not inverse:
+        # forward transform
+        A *= u
+    else:
+        # backward transform
+        A /= xp.conj(u)
+    A = irfft(A, n, axis=-1)
+    A = xp.flip(A, axis=-1)
+
+    return A

venv/lib/python3.10/site-packages/scipy/fft/_helper.py

@@ -0,0 +1,313 @@
+from functools import update_wrapper, lru_cache
+import inspect
+
+from ._pocketfft import helper as _helper
+
+import numpy as np
+from scipy._lib._array_api import array_namespace
+
+
+def next_fast_len(target, real=False):
+    """Find the next fast size of input data to ``fft``, for zero-padding, etc.
+
+    SciPy's FFT algorithms gain their speed by a recursive divide and conquer
+    strategy. This relies on efficient functions for small prime factors of the
+    input length. Thus, the transforms are fastest when using composites of the
+    prime factors handled by the fft implementation. If there are efficient
+    functions for all radices <= `n`, then the result will be a number `x`
+    >= ``target`` with only prime factors < `n`. (Also known as `n`-smooth
+    numbers)
+
+    Parameters
+    ----------
+    target : int
+        Length to start searching from. Must be a positive integer.
+    real : bool, optional
+        True if the FFT involves real input or output (e.g., `rfft` or `hfft`
+        but not `fft`). Defaults to False.
+
+    Returns
+    -------
+    out : int
+        The smallest fast length greater than or equal to ``target``.
+
+    Notes
+    -----
+    The result of this function may change in future as performance
+    considerations change, for example, if new prime factors are added.
+
+    Calling `fft` or `ifft` with real input data performs an ``'R2C'``
+    transform internally.
+
+    Examples
+    --------
+    On a particular machine, an FFT of prime length takes 11.4 ms:
+
+    >>> from scipy import fft
+    >>> import numpy as np
+    >>> rng = np.random.default_rng()
+    >>> min_len = 93059  # prime length is worst case for speed
+    >>> a = rng.standard_normal(min_len)
+    >>> b = fft.fft(a)
+
+    Zero-padding to the next regular length reduces computation time to
+    1.6 ms, a speedup of 7.3 times:
+
+    >>> fft.next_fast_len(min_len, real=True)
+    93312
+    >>> b = fft.fft(a, 93312)
+
+    Rounding up to the next power of 2 is not optimal, taking 3.0 ms to
+    compute; 1.9 times longer than the size given by ``next_fast_len``:
+
+    >>> b = fft.fft(a, 131072)
+
+    """
+    pass
+
+
+# Directly wrap the c-function good_size but take the docstring etc., from the
+# next_fast_len function above
+_sig = inspect.signature(next_fast_len)
+next_fast_len = update_wrapper(lru_cache(_helper.good_size), next_fast_len)
+next_fast_len.__wrapped__ = _helper.good_size
+next_fast_len.__signature__ = _sig
+
+
+def _init_nd_shape_and_axes(x, shape, axes):
+    """Handle shape and axes arguments for N-D transforms.
+
+    Returns the shape and axes in a standard form, taking into account negative
+    values and checking for various potential errors.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    shape : int or array_like of ints or None
+        The shape of the result. If both `shape` and `axes` (see below) are
+        None, `shape` is ``x.shape``; if `shape` is None but `axes` is
+        not None, then `shape` is ``numpy.take(x.shape, axes, axis=0)``.
+        If `shape` is -1, the size of the corresponding dimension of `x` is
+        used.
+    axes : int or array_like of ints or None
+        Axes along which the calculation is computed.
+        The default is over all axes.
+        Negative indices are automatically converted to their positive
+        counterparts.
+
+    Returns
+    -------
+    shape : tuple
+        The shape of the result as a tuple of integers.
+    axes : list
+        Axes along which the calculation is computed, as a list of integers.
+
+    """
+    x = np.asarray(x)
+    return _helper._init_nd_shape_and_axes(x, shape, axes)
+
+
+def fftfreq(n, d=1.0, *, xp=None, device=None):
+    """Return the Discrete Fourier Transform sample frequencies.
+
+    The returned float array `f` contains the frequency bin centers in cycles
+    per unit of the sample spacing (with zero at the start).  For instance, if
+    the sample spacing is in seconds, then the frequency unit is cycles/second.
+
+    Given a window length `n` and a sample spacing `d`::
+
+      f = [0, 1, ...,   n/2-1,     -n/2, ..., -1] / (d*n)   if n is even
+      f = [0, 1, ..., (n-1)/2, -(n-1)/2, ..., -1] / (d*n)   if n is odd
+
+    Parameters
+    ----------
+    n : int
+        Window length.
+    d : scalar, optional
+        Sample spacing (inverse of the sampling rate). Defaults to 1.
+    xp : array_namespace, optional
+        The namespace for the return array. Default is None, where NumPy is used.
+    device : device, optional
+        The device for the return array.
+        Only valid when `xp.fft.fftfreq` implements the device parameter.
+     
+    Returns
+    -------
+    f : ndarray
+        Array of length `n` containing the sample frequencies.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> import scipy.fft
+    >>> signal = np.array([-2, 8, 6, 4, 1, 0, 3, 5], dtype=float)
+    >>> fourier = scipy.fft.fft(signal)
+    >>> n = signal.size
+    >>> timestep = 0.1
+    >>> freq = scipy.fft.fftfreq(n, d=timestep)
+    >>> freq
+    array([ 0.  ,  1.25,  2.5 , ..., -3.75, -2.5 , -1.25])
+
+    """
+    xp = np if xp is None else xp
+    # numpy does not yet support the `device` keyword
+    # `xp.__name__ != 'numpy'` should be removed when numpy is compatible
+    if hasattr(xp, 'fft') and xp.__name__ != 'numpy':
+        return xp.fft.fftfreq(n, d=d, device=device)
+    if device is not None:
+        raise ValueError('device parameter is not supported for input array type')
+    return np.fft.fftfreq(n, d=d)
+
+
+def rfftfreq(n, d=1.0, *, xp=None, device=None):
+    """Return the Discrete Fourier Transform sample frequencies
+    (for usage with rfft, irfft).
+
+    The returned float array `f` contains the frequency bin centers in cycles
+    per unit of the sample spacing (with zero at the start).  For instance, if
+    the sample spacing is in seconds, then the frequency unit is cycles/second.
+
+    Given a window length `n` and a sample spacing `d`::
+
+      f = [0, 1, ...,     n/2-1,     n/2] / (d*n)   if n is even
+      f = [0, 1, ..., (n-1)/2-1, (n-1)/2] / (d*n)   if n is odd
+
+    Unlike `fftfreq` (but like `scipy.fftpack.rfftfreq`)
+    the Nyquist frequency component is considered to be positive.
+
+    Parameters
+    ----------
+    n : int
+        Window length.
+    d : scalar, optional
+        Sample spacing (inverse of the sampling rate). Defaults to 1.
+    xp : array_namespace, optional
+        The namespace for the return array. Default is None, where NumPy is used.
+    device : device, optional
+        The device for the return array.
+        Only valid when `xp.fft.rfftfreq` implements the device parameter.
+
+    Returns
+    -------
+    f : ndarray
+        Array of length ``n//2 + 1`` containing the sample frequencies.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> import scipy.fft
+    >>> signal = np.array([-2, 8, 6, 4, 1, 0, 3, 5, -3, 4], dtype=float)
+    >>> fourier = scipy.fft.rfft(signal)
+    >>> n = signal.size
+    >>> sample_rate = 100
+    >>> freq = scipy.fft.fftfreq(n, d=1./sample_rate)
+    >>> freq
+    array([  0.,  10.,  20., ..., -30., -20., -10.])
+    >>> freq = scipy.fft.rfftfreq(n, d=1./sample_rate)
+    >>> freq
+    array([  0.,  10.,  20.,  30.,  40.,  50.])
+
+    """
+    xp = np if xp is None else xp
+    # numpy does not yet support the `device` keyword
+    # `xp.__name__ != 'numpy'` should be removed when numpy is compatible
+    if hasattr(xp, 'fft') and xp.__name__ != 'numpy':
+        return xp.fft.rfftfreq(n, d=d, device=device)
+    if device is not None:
+        raise ValueError('device parameter is not supported for input array type')
+    return np.fft.rfftfreq(n, d=d)
+
+
+def fftshift(x, axes=None):
+    """Shift the zero-frequency component to the center of the spectrum.
+
+    This function swaps half-spaces for all axes listed (defaults to all).
+    Note that ``y[0]`` is the Nyquist component only if ``len(x)`` is even.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array.
+    axes : int or shape tuple, optional
+        Axes over which to shift.  Default is None, which shifts all axes.
+
+    Returns
+    -------
+    y : ndarray
+        The shifted array.
+
+    See Also
+    --------
+    ifftshift : The inverse of `fftshift`.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> freqs = np.fft.fftfreq(10, 0.1)
+    >>> freqs
+    array([ 0.,  1.,  2., ..., -3., -2., -1.])
+    >>> np.fft.fftshift(freqs)
+    array([-5., -4., -3., -2., -1.,  0.,  1.,  2.,  3.,  4.])
+
+    Shift the zero-frequency component only along the second axis:
+
+    >>> freqs = np.fft.fftfreq(9, d=1./9).reshape(3, 3)
+    >>> freqs
+    array([[ 0.,  1.,  2.],
+           [ 3.,  4., -4.],
+           [-3., -2., -1.]])
+    >>> np.fft.fftshift(freqs, axes=(1,))
+    array([[ 2.,  0.,  1.],
+           [-4.,  3.,  4.],
+           [-1., -3., -2.]])
+
+    """
+    xp = array_namespace(x)
+    if hasattr(xp, 'fft'):
+        return xp.fft.fftshift(x, axes=axes)
+    x = np.asarray(x)
+    y = np.fft.fftshift(x, axes=axes)
+    return xp.asarray(y)
+
+
+def ifftshift(x, axes=None):
+    """The inverse of `fftshift`. Although identical for even-length `x`, the
+    functions differ by one sample for odd-length `x`.
+
+    Parameters
+    ----------
+    x : array_like
+        Input array.
+    axes : int or shape tuple, optional
+        Axes over which to calculate.  Defaults to None, which shifts all axes.
+
+    Returns
+    -------
+    y : ndarray
+        The shifted array.
+
+    See Also
+    --------
+    fftshift : Shift zero-frequency component to the center of the spectrum.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> freqs = np.fft.fftfreq(9, d=1./9).reshape(3, 3)
+    >>> freqs
+    array([[ 0.,  1.,  2.],
+           [ 3.,  4., -4.],
+           [-3., -2., -1.]])
+    >>> np.fft.ifftshift(np.fft.fftshift(freqs))
+    array([[ 0.,  1.,  2.],
+           [ 3.,  4., -4.],
+           [-3., -2., -1.]])
+
+    """
+    xp = array_namespace(x)
+    if hasattr(xp, 'fft'):
+        return xp.fft.ifftshift(x, axes=axes)
+    x = np.asarray(x)
+    y = np.fft.ifftshift(x, axes=axes)
+    return xp.asarray(y)

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/LICENSE.md

@@ -0,0 +1,25 @@
+Copyright (C) 2010-2019 Max-Planck-Society
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+* Redistributions in binary form must reproduce the above copyright notice, this
+  list of conditions and the following disclaimer in the documentation and/or
+  other materials provided with the distribution.
+* Neither the name of the copyright holder nor the names of its contributors may
+  be used to endorse or promote products derived from this software without
+  specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/__init__.py

@@ -0,0 +1,9 @@
+""" FFT backend using pypocketfft """
+
+from .basic import *
+from .realtransforms import *
+from .helper import *
+
+from scipy._lib._testutils import PytestTester
+test = PytestTester(__name__)
+del PytestTester

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/basic.py

@@ -0,0 +1,251 @@
+"""
+Discrete Fourier Transforms - basic.py
+"""
+import numpy as np
+import functools
+from . import pypocketfft as pfft
+from .helper import (_asfarray, _init_nd_shape_and_axes, _datacopied,
+                     _fix_shape, _fix_shape_1d, _normalization,
+                     _workers)
+
+def c2c(forward, x, n=None, axis=-1, norm=None, overwrite_x=False,
+        workers=None, *, plan=None):
+    """ Return discrete Fourier transform of real or complex sequence. """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+    overwrite_x = overwrite_x or _datacopied(tmp, x)
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    if n is not None:
+        tmp, copied = _fix_shape_1d(tmp, n, axis)
+        overwrite_x = overwrite_x or copied
+    elif tmp.shape[axis] < 1:
+        message = f"invalid number of data points ({tmp.shape[axis]}) specified"
+        raise ValueError(message)
+
+    out = (tmp if overwrite_x and tmp.dtype.kind == 'c' else None)
+
+    return pfft.c2c(tmp, (axis,), forward, norm, out, workers)
+
+
+fft = functools.partial(c2c, True)
+fft.__name__ = 'fft'
+ifft = functools.partial(c2c, False)
+ifft.__name__ = 'ifft'
+
+
+def r2c(forward, x, n=None, axis=-1, norm=None, overwrite_x=False,
+        workers=None, *, plan=None):
+    """
+    Discrete Fourier transform of a real sequence.
+    """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    if not np.isrealobj(tmp):
+        raise TypeError("x must be a real sequence")
+
+    if n is not None:
+        tmp, _ = _fix_shape_1d(tmp, n, axis)
+    elif tmp.shape[axis] < 1:
+        raise ValueError(f"invalid number of data points ({tmp.shape[axis]}) specified")
+
+    # Note: overwrite_x is not utilised
+    return pfft.r2c(tmp, (axis,), forward, norm, None, workers)
+
+
+rfft = functools.partial(r2c, True)
+rfft.__name__ = 'rfft'
+ihfft = functools.partial(r2c, False)
+ihfft.__name__ = 'ihfft'
+
+
+def c2r(forward, x, n=None, axis=-1, norm=None, overwrite_x=False,
+        workers=None, *, plan=None):
+    """
+    Return inverse discrete Fourier transform of real sequence x.
+    """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    # TODO: Optimize for hermitian and real?
+    if np.isrealobj(tmp):
+        tmp = tmp + 0.j
+
+    # Last axis utilizes hermitian symmetry
+    if n is None:
+        n = (tmp.shape[axis] - 1) * 2
+        if n < 1:
+            raise ValueError(f"Invalid number of data points ({n}) specified")
+    else:
+        tmp, _ = _fix_shape_1d(tmp, (n//2) + 1, axis)
+
+    # Note: overwrite_x is not utilized
+    return pfft.c2r(tmp, (axis,), n, forward, norm, None, workers)
+
+
+hfft = functools.partial(c2r, True)
+hfft.__name__ = 'hfft'
+irfft = functools.partial(c2r, False)
+irfft.__name__ = 'irfft'
+
+
+def hfft2(x, s=None, axes=(-2,-1), norm=None, overwrite_x=False, workers=None,
+          *, plan=None):
+    """
+    2-D discrete Fourier transform of a Hermitian sequence
+    """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    return hfftn(x, s, axes, norm, overwrite_x, workers)
+
+
+def ihfft2(x, s=None, axes=(-2,-1), norm=None, overwrite_x=False, workers=None,
+           *, plan=None):
+    """
+    2-D discrete inverse Fourier transform of a Hermitian sequence
+    """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    return ihfftn(x, s, axes, norm, overwrite_x, workers)
+
+
+def c2cn(forward, x, s=None, axes=None, norm=None, overwrite_x=False,
+         workers=None, *, plan=None):
+    """
+    Return multidimensional discrete Fourier transform.
+    """
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+
+    shape, axes = _init_nd_shape_and_axes(tmp, s, axes)
+    overwrite_x = overwrite_x or _datacopied(tmp, x)
+    workers = _workers(workers)
+
+    if len(axes) == 0:
+        return x
+
+    tmp, copied = _fix_shape(tmp, shape, axes)
+    overwrite_x = overwrite_x or copied
+
+    norm = _normalization(norm, forward)
+    out = (tmp if overwrite_x and tmp.dtype.kind == 'c' else None)
+
+    return pfft.c2c(tmp, axes, forward, norm, out, workers)
+
+
+fftn = functools.partial(c2cn, True)
+fftn.__name__ = 'fftn'
+ifftn = functools.partial(c2cn, False)
+ifftn.__name__ = 'ifftn'
+
+def r2cn(forward, x, s=None, axes=None, norm=None, overwrite_x=False,
+         workers=None, *, plan=None):
+    """Return multidimensional discrete Fourier transform of real input"""
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+
+    if not np.isrealobj(tmp):
+        raise TypeError("x must be a real sequence")
+
+    shape, axes = _init_nd_shape_and_axes(tmp, s, axes)
+    tmp, _ = _fix_shape(tmp, shape, axes)
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    if len(axes) == 0:
+        raise ValueError("at least 1 axis must be transformed")
+
+    # Note: overwrite_x is not utilized
+    return pfft.r2c(tmp, axes, forward, norm, None, workers)
+
+
+rfftn = functools.partial(r2cn, True)
+rfftn.__name__ = 'rfftn'
+ihfftn = functools.partial(r2cn, False)
+ihfftn.__name__ = 'ihfftn'
+
+
+def c2rn(forward, x, s=None, axes=None, norm=None, overwrite_x=False,
+         workers=None, *, plan=None):
+    """Multidimensional inverse discrete fourier transform with real output"""
+    if plan is not None:
+        raise NotImplementedError('Passing a precomputed plan is not yet '
+                                  'supported by scipy.fft functions')
+    tmp = _asfarray(x)
+
+    # TODO: Optimize for hermitian and real?
+    if np.isrealobj(tmp):
+        tmp = tmp + 0.j
+
+    noshape = s is None
+    shape, axes = _init_nd_shape_and_axes(tmp, s, axes)
+
+    if len(axes) == 0:
+        raise ValueError("at least 1 axis must be transformed")
+
+    shape = list(shape)
+    if noshape:
+        shape[-1] = (x.shape[axes[-1]] - 1) * 2
+
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    # Last axis utilizes hermitian symmetry
+    lastsize = shape[-1]
+    shape[-1] = (shape[-1] // 2) + 1
+
+    tmp, _ = tuple(_fix_shape(tmp, shape, axes))
+
+    # Note: overwrite_x is not utilized
+    return pfft.c2r(tmp, axes, lastsize, forward, norm, None, workers)
+
+
+hfftn = functools.partial(c2rn, True)
+hfftn.__name__ = 'hfftn'
+irfftn = functools.partial(c2rn, False)
+irfftn.__name__ = 'irfftn'
+
+
+def r2r_fftpack(forward, x, n=None, axis=-1, norm=None, overwrite_x=False):
+    """FFT of a real sequence, returning fftpack half complex format"""
+    tmp = _asfarray(x)
+    overwrite_x = overwrite_x or _datacopied(tmp, x)
+    norm = _normalization(norm, forward)
+    workers = _workers(None)
+
+    if tmp.dtype.kind == 'c':
+        raise TypeError('x must be a real sequence')
+
+    if n is not None:
+        tmp, copied = _fix_shape_1d(tmp, n, axis)
+        overwrite_x = overwrite_x or copied
+    elif tmp.shape[axis] < 1:
+        raise ValueError(f"invalid number of data points ({tmp.shape[axis]}) specified")
+
+    out = (tmp if overwrite_x else None)
+
+    return pfft.r2r_fftpack(tmp, (axis,), forward, forward, norm, out, workers)
+
+
+rfft_fftpack = functools.partial(r2r_fftpack, True)
+rfft_fftpack.__name__ = 'rfft_fftpack'
+irfft_fftpack = functools.partial(r2r_fftpack, False)
+irfft_fftpack.__name__ = 'irfft_fftpack'

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/helper.py

@@ -0,0 +1,221 @@
+from numbers import Number
+import operator
+import os
+import threading
+import contextlib
+
+import numpy as np
+
+from scipy._lib._util import copy_if_needed
+
+# good_size is exposed (and used) from this import
+from .pypocketfft import good_size
+
+
+__all__ = ['good_size', 'set_workers', 'get_workers']
+
+_config = threading.local()
+_cpu_count = os.cpu_count()
+
+
+def _iterable_of_int(x, name=None):
+    """Convert ``x`` to an iterable sequence of int
+
+    Parameters
+    ----------
+    x : value, or sequence of values, convertible to int
+    name : str, optional
+        Name of the argument being converted, only used in the error message
+
+    Returns
+    -------
+    y : ``List[int]``
+    """
+    if isinstance(x, Number):
+        x = (x,)
+
+    try:
+        x = [operator.index(a) for a in x]
+    except TypeError as e:
+        name = name or "value"
+        raise ValueError(f"{name} must be a scalar or iterable of integers") from e
+
+    return x
+
+
+def _init_nd_shape_and_axes(x, shape, axes):
+    """Handles shape and axes arguments for nd transforms"""
+    noshape = shape is None
+    noaxes = axes is None
+
+    if not noaxes:
+        axes = _iterable_of_int(axes, 'axes')
+        axes = [a + x.ndim if a < 0 else a for a in axes]
+
+        if any(a >= x.ndim or a < 0 for a in axes):
+            raise ValueError("axes exceeds dimensionality of input")
+        if len(set(axes)) != len(axes):
+            raise ValueError("all axes must be unique")
+
+    if not noshape:
+        shape = _iterable_of_int(shape, 'shape')
+
+        if axes and len(axes) != len(shape):
+            raise ValueError("when given, axes and shape arguments"
+                             " have to be of the same length")
+        if noaxes:
+            if len(shape) > x.ndim:
+                raise ValueError("shape requires more axes than are present")
+            axes = range(x.ndim - len(shape), x.ndim)
+
+        shape = [x.shape[a] if s == -1 else s for s, a in zip(shape, axes)]
+    elif noaxes:
+        shape = list(x.shape)
+        axes = range(x.ndim)
+    else:
+        shape = [x.shape[a] for a in axes]
+
+    if any(s < 1 for s in shape):
+        raise ValueError(
+            f"invalid number of data points ({shape}) specified")
+
+    return tuple(shape), list(axes)
+
+
+def _asfarray(x):
+    """
+    Convert to array with floating or complex dtype.
+
+    float16 values are also promoted to float32.
+    """
+    if not hasattr(x, "dtype"):
+        x = np.asarray(x)
+
+    if x.dtype == np.float16:
+        return np.asarray(x, np.float32)
+    elif x.dtype.kind not in 'fc':
+        return np.asarray(x, np.float64)
+
+    # Require native byte order
+    dtype = x.dtype.newbyteorder('=')
+    # Always align input
+    copy = True if not x.flags['ALIGNED'] else copy_if_needed
+    return np.array(x, dtype=dtype, copy=copy)
+
+def _datacopied(arr, original):
+    """
+    Strict check for `arr` not sharing any data with `original`,
+    under the assumption that arr = asarray(original)
+    """
+    if arr is original:
+        return False
+    if not isinstance(original, np.ndarray) and hasattr(original, '__array__'):
+        return False
+    return arr.base is None
+
+
+def _fix_shape(x, shape, axes):
+    """Internal auxiliary function for _raw_fft, _raw_fftnd."""
+    must_copy = False
+
+    # Build an nd slice with the dimensions to be read from x
+    index = [slice(None)]*x.ndim
+    for n, ax in zip(shape, axes):
+        if x.shape[ax] >= n:
+            index[ax] = slice(0, n)
+        else:
+            index[ax] = slice(0, x.shape[ax])
+            must_copy = True
+
+    index = tuple(index)
+
+    if not must_copy:
+        return x[index], False
+
+    s = list(x.shape)
+    for n, axis in zip(shape, axes):
+        s[axis] = n
+
+    z = np.zeros(s, x.dtype)
+    z[index] = x[index]
+    return z, True
+
+
+def _fix_shape_1d(x, n, axis):
+    if n < 1:
+        raise ValueError(
+            f"invalid number of data points ({n}) specified")
+
+    return _fix_shape(x, (n,), (axis,))
+
+
+_NORM_MAP = {None: 0, 'backward': 0, 'ortho': 1, 'forward': 2}
+
+
+def _normalization(norm, forward):
+    """Returns the pypocketfft normalization mode from the norm argument"""
+    try:
+        inorm = _NORM_MAP[norm]
+        return inorm if forward else (2 - inorm)
+    except KeyError:
+        raise ValueError(
+            f'Invalid norm value {norm!r}, should '
+            'be "backward", "ortho" or "forward"') from None
+
+
+def _workers(workers):
+    if workers is None:
+        return getattr(_config, 'default_workers', 1)
+
+    if workers < 0:
+        if workers >= -_cpu_count:
+            workers += 1 + _cpu_count
+        else:
+            raise ValueError(f"workers value out of range; got {workers}, must not be"
+                             f" less than {-_cpu_count}")
+    elif workers == 0:
+        raise ValueError("workers must not be zero")
+
+    return workers
+
+
+@contextlib.contextmanager
+def set_workers(workers):
+    """Context manager for the default number of workers used in `scipy.fft`
+
+    Parameters
+    ----------
+    workers : int
+        The default number of workers to use
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> from scipy import fft, signal
+    >>> rng = np.random.default_rng()
+    >>> x = rng.standard_normal((128, 64))
+    >>> with fft.set_workers(4):
+    ...     y = signal.fftconvolve(x, x)
+
+    """
+    old_workers = get_workers()
+    _config.default_workers = _workers(operator.index(workers))
+    try:
+        yield
+    finally:
+        _config.default_workers = old_workers
+
+
+def get_workers():
+    """Returns the default number of workers within the current context
+
+    Examples
+    --------
+    >>> from scipy import fft
+    >>> fft.get_workers()
+    1
+    >>> with fft.set_workers(4):
+    ...     fft.get_workers()
+    4
+    """
+    return getattr(_config, 'default_workers', 1)

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/realtransforms.py

@@ -0,0 +1,109 @@
+import numpy as np
+from . import pypocketfft as pfft
+from .helper import (_asfarray, _init_nd_shape_and_axes, _datacopied,
+                     _fix_shape, _fix_shape_1d, _normalization, _workers)
+import functools
+
+
+def _r2r(forward, transform, x, type=2, n=None, axis=-1, norm=None,
+         overwrite_x=False, workers=None, orthogonalize=None):
+    """Forward or backward 1-D DCT/DST
+
+    Parameters
+    ----------
+    forward : bool
+        Transform direction (determines type and normalisation)
+    transform : {pypocketfft.dct, pypocketfft.dst}
+        The transform to perform
+    """
+    tmp = _asfarray(x)
+    overwrite_x = overwrite_x or _datacopied(tmp, x)
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+
+    if not forward:
+        if type == 2:
+            type = 3
+        elif type == 3:
+            type = 2
+
+    if n is not None:
+        tmp, copied = _fix_shape_1d(tmp, n, axis)
+        overwrite_x = overwrite_x or copied
+    elif tmp.shape[axis] < 1:
+        raise ValueError(f"invalid number of data points ({tmp.shape[axis]}) specified")
+
+    out = (tmp if overwrite_x else None)
+
+    # For complex input, transform real and imaginary components separably
+    if np.iscomplexobj(x):
+        out = np.empty_like(tmp) if out is None else out
+        transform(tmp.real, type, (axis,), norm, out.real, workers)
+        transform(tmp.imag, type, (axis,), norm, out.imag, workers)
+        return out
+
+    return transform(tmp, type, (axis,), norm, out, workers, orthogonalize)
+
+
+dct = functools.partial(_r2r, True, pfft.dct)
+dct.__name__ = 'dct'
+idct = functools.partial(_r2r, False, pfft.dct)
+idct.__name__ = 'idct'
+
+dst = functools.partial(_r2r, True, pfft.dst)
+dst.__name__ = 'dst'
+idst = functools.partial(_r2r, False, pfft.dst)
+idst.__name__ = 'idst'
+
+
+def _r2rn(forward, transform, x, type=2, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, orthogonalize=None):
+    """Forward or backward nd DCT/DST
+
+    Parameters
+    ----------
+    forward : bool
+        Transform direction (determines type and normalisation)
+    transform : {pypocketfft.dct, pypocketfft.dst}
+        The transform to perform
+    """
+    tmp = _asfarray(x)
+
+    shape, axes = _init_nd_shape_and_axes(tmp, s, axes)
+    overwrite_x = overwrite_x or _datacopied(tmp, x)
+
+    if len(axes) == 0:
+        return x
+
+    tmp, copied = _fix_shape(tmp, shape, axes)
+    overwrite_x = overwrite_x or copied
+
+    if not forward:
+        if type == 2:
+            type = 3
+        elif type == 3:
+            type = 2
+
+    norm = _normalization(norm, forward)
+    workers = _workers(workers)
+    out = (tmp if overwrite_x else None)
+
+    # For complex input, transform real and imaginary components separably
+    if np.iscomplexobj(x):
+        out = np.empty_like(tmp) if out is None else out
+        transform(tmp.real, type, axes, norm, out.real, workers)
+        transform(tmp.imag, type, axes, norm, out.imag, workers)
+        return out
+
+    return transform(tmp, type, axes, norm, out, workers, orthogonalize)
+
+
+dctn = functools.partial(_r2rn, True, pfft.dct)
+dctn.__name__ = 'dctn'
+idctn = functools.partial(_r2rn, False, pfft.dct)
+idctn.__name__ = 'idctn'
+
+dstn = functools.partial(_r2rn, True, pfft.dst)
+dstn.__name__ = 'dstn'
+idstn = functools.partial(_r2rn, False, pfft.dst)
+idstn.__name__ = 'idstn'

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/tests/test_basic.py

@@ -0,0 +1,1005 @@
+# Created by Pearu Peterson, September 2002
+
+from numpy.testing import (assert_, assert_equal, assert_array_almost_equal,
+                           assert_array_almost_equal_nulp, assert_array_less,
+                           assert_allclose)
+import pytest
+from pytest import raises as assert_raises
+from scipy.fft._pocketfft import (ifft, fft, fftn, ifftn,
+                                  rfft, irfft, rfftn, irfftn,
+                                  hfft, ihfft, hfftn, ihfftn)
+
+from numpy import (arange, array, asarray, zeros, dot, exp, pi,
+                   swapaxes, cdouble)
+import numpy as np
+import numpy.fft
+from numpy.random import rand
+
+# "large" composite numbers supported by FFT._PYPOCKETFFT
+LARGE_COMPOSITE_SIZES = [
+    2**13,
+    2**5 * 3**5,
+    2**3 * 3**3 * 5**2,
+]
+SMALL_COMPOSITE_SIZES = [
+    2,
+    2*3*5,
+    2*2*3*3,
+]
+# prime
+LARGE_PRIME_SIZES = [
+    2011
+]
+SMALL_PRIME_SIZES = [
+    29
+]
+
+
+def _assert_close_in_norm(x, y, rtol, size, rdt):
+    # helper function for testing
+    err_msg = f"size: {size}  rdt: {rdt}"
+    assert_array_less(np.linalg.norm(x - y), rtol*np.linalg.norm(x), err_msg)
+
+
+def random(size):
+    return rand(*size)
+
+def swap_byteorder(arr):
+    """Returns the same array with swapped byteorder"""
+    dtype = arr.dtype.newbyteorder('S')
+    return arr.astype(dtype)
+
+def direct_dft(x):
+    x = asarray(x)
+    n = len(x)
+    y = zeros(n, dtype=cdouble)
+    w = -arange(n)*(2j*pi/n)
+    for i in range(n):
+        y[i] = dot(exp(i*w), x)
+    return y
+
+
+def direct_idft(x):
+    x = asarray(x)
+    n = len(x)
+    y = zeros(n, dtype=cdouble)
+    w = arange(n)*(2j*pi/n)
+    for i in range(n):
+        y[i] = dot(exp(i*w), x)/n
+    return y
+
+
+def direct_dftn(x):
+    x = asarray(x)
+    for axis in range(x.ndim):
+        x = fft(x, axis=axis)
+    return x
+
+
+def direct_idftn(x):
+    x = asarray(x)
+    for axis in range(x.ndim):
+        x = ifft(x, axis=axis)
+    return x
+
+
+def direct_rdft(x):
+    x = asarray(x)
+    n = len(x)
+    w = -arange(n)*(2j*pi/n)
+    y = zeros(n//2+1, dtype=cdouble)
+    for i in range(n//2+1):
+        y[i] = dot(exp(i*w), x)
+    return y
+
+
+def direct_irdft(x, n):
+    x = asarray(x)
+    x1 = zeros(n, dtype=cdouble)
+    for i in range(n//2+1):
+        x1[i] = x[i]
+        if i > 0 and 2*i < n:
+            x1[n-i] = np.conj(x[i])
+    return direct_idft(x1).real
+
+
+def direct_rdftn(x):
+    return fftn(rfft(x), axes=range(x.ndim - 1))
+
+
+class _TestFFTBase:
+    def setup_method(self):
+        self.cdt = None
+        self.rdt = None
+        np.random.seed(1234)
+
+    def test_definition(self):
+        x = np.array([1,2,3,4+1j,1,2,3,4+2j], dtype=self.cdt)
+        y = fft(x)
+        assert_equal(y.dtype, self.cdt)
+        y1 = direct_dft(x)
+        assert_array_almost_equal(y,y1)
+        x = np.array([1,2,3,4+0j,5], dtype=self.cdt)
+        assert_array_almost_equal(fft(x),direct_dft(x))
+
+    def test_n_argument_real(self):
+        x1 = np.array([1,2,3,4], dtype=self.rdt)
+        x2 = np.array([1,2,3,4], dtype=self.rdt)
+        y = fft([x1,x2],n=4)
+        assert_equal(y.dtype, self.cdt)
+        assert_equal(y.shape,(2,4))
+        assert_array_almost_equal(y[0],direct_dft(x1))
+        assert_array_almost_equal(y[1],direct_dft(x2))
+
+    def _test_n_argument_complex(self):
+        x1 = np.array([1,2,3,4+1j], dtype=self.cdt)
+        x2 = np.array([1,2,3,4+1j], dtype=self.cdt)
+        y = fft([x1,x2],n=4)
+        assert_equal(y.dtype, self.cdt)
+        assert_equal(y.shape,(2,4))
+        assert_array_almost_equal(y[0],direct_dft(x1))
+        assert_array_almost_equal(y[1],direct_dft(x2))
+
+    def test_djbfft(self):
+        for i in range(2,14):
+            n = 2**i
+            x = np.arange(n)
+            y = fft(x.astype(complex))
+            y2 = numpy.fft.fft(x)
+            assert_array_almost_equal(y,y2)
+            y = fft(x)
+            assert_array_almost_equal(y,y2)
+
+    def test_invalid_sizes(self):
+        assert_raises(ValueError, fft, [])
+        assert_raises(ValueError, fft, [[1,1],[2,2]], -5)
+
+
+class TestLongDoubleFFT(_TestFFTBase):
+    def setup_method(self):
+        self.cdt = np.clongdouble
+        self.rdt = np.longdouble
+
+
+class TestDoubleFFT(_TestFFTBase):
+    def setup_method(self):
+        self.cdt = np.cdouble
+        self.rdt = np.float64
+
+
+class TestSingleFFT(_TestFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex64
+        self.rdt = np.float32
+
+
+class TestFloat16FFT:
+
+    def test_1_argument_real(self):
+        x1 = np.array([1, 2, 3, 4], dtype=np.float16)
+        y = fft(x1, n=4)
+        assert_equal(y.dtype, np.complex64)
+        assert_equal(y.shape, (4, ))
+        assert_array_almost_equal(y, direct_dft(x1.astype(np.float32)))
+
+    def test_n_argument_real(self):
+        x1 = np.array([1, 2, 3, 4], dtype=np.float16)
+        x2 = np.array([1, 2, 3, 4], dtype=np.float16)
+        y = fft([x1, x2], n=4)
+        assert_equal(y.dtype, np.complex64)
+        assert_equal(y.shape, (2, 4))
+        assert_array_almost_equal(y[0], direct_dft(x1.astype(np.float32)))
+        assert_array_almost_equal(y[1], direct_dft(x2.astype(np.float32)))
+
+
+class _TestIFFTBase:
+    def setup_method(self):
+        np.random.seed(1234)
+
+    def test_definition(self):
+        x = np.array([1,2,3,4+1j,1,2,3,4+2j], self.cdt)
+        y = ifft(x)
+        y1 = direct_idft(x)
+        assert_equal(y.dtype, self.cdt)
+        assert_array_almost_equal(y,y1)
+
+        x = np.array([1,2,3,4+0j,5], self.cdt)
+        assert_array_almost_equal(ifft(x),direct_idft(x))
+
+    def test_definition_real(self):
+        x = np.array([1,2,3,4,1,2,3,4], self.rdt)
+        y = ifft(x)
+        assert_equal(y.dtype, self.cdt)
+        y1 = direct_idft(x)
+        assert_array_almost_equal(y,y1)
+
+        x = np.array([1,2,3,4,5], dtype=self.rdt)
+        assert_equal(y.dtype, self.cdt)
+        assert_array_almost_equal(ifft(x),direct_idft(x))
+
+    def test_djbfft(self):
+        for i in range(2,14):
+            n = 2**i
+            x = np.arange(n)
+            y = ifft(x.astype(self.cdt))
+            y2 = numpy.fft.ifft(x.astype(self.cdt))
+            assert_allclose(y,y2, rtol=self.rtol, atol=self.atol)
+            y = ifft(x)
+            assert_allclose(y,y2, rtol=self.rtol, atol=self.atol)
+
+    def test_random_complex(self):
+        for size in [1,51,111,100,200,64,128,256,1024]:
+            x = random([size]).astype(self.cdt)
+            x = random([size]).astype(self.cdt) + 1j*x
+            y1 = ifft(fft(x))
+            y2 = fft(ifft(x))
+            assert_equal(y1.dtype, self.cdt)
+            assert_equal(y2.dtype, self.cdt)
+            assert_array_almost_equal(y1, x)
+            assert_array_almost_equal(y2, x)
+
+    def test_random_real(self):
+        for size in [1,51,111,100,200,64,128,256,1024]:
+            x = random([size]).astype(self.rdt)
+            y1 = ifft(fft(x))
+            y2 = fft(ifft(x))
+            assert_equal(y1.dtype, self.cdt)
+            assert_equal(y2.dtype, self.cdt)
+            assert_array_almost_equal(y1, x)
+            assert_array_almost_equal(y2, x)
+
+    def test_size_accuracy(self):
+        # Sanity check for the accuracy for prime and non-prime sized inputs
+        for size in LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES:
+            np.random.seed(1234)
+            x = np.random.rand(size).astype(self.rdt)
+            y = ifft(fft(x))
+            _assert_close_in_norm(x, y, self.rtol, size, self.rdt)
+            y = fft(ifft(x))
+            _assert_close_in_norm(x, y, self.rtol, size, self.rdt)
+
+            x = (x + 1j*np.random.rand(size)).astype(self.cdt)
+            y = ifft(fft(x))
+            _assert_close_in_norm(x, y, self.rtol, size, self.rdt)
+            y = fft(ifft(x))
+            _assert_close_in_norm(x, y, self.rtol, size, self.rdt)
+
+    def test_invalid_sizes(self):
+        assert_raises(ValueError, ifft, [])
+        assert_raises(ValueError, ifft, [[1,1],[2,2]], -5)
+
+
+@pytest.mark.skipif(np.longdouble is np.float64,
+                    reason="Long double is aliased to double")
+class TestLongDoubleIFFT(_TestIFFTBase):
+    def setup_method(self):
+        self.cdt = np.clongdouble
+        self.rdt = np.longdouble
+        self.rtol = 1e-10
+        self.atol = 1e-10
+
+
+class TestDoubleIFFT(_TestIFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex128
+        self.rdt = np.float64
+        self.rtol = 1e-10
+        self.atol = 1e-10
+
+
+class TestSingleIFFT(_TestIFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex64
+        self.rdt = np.float32
+        self.rtol = 1e-5
+        self.atol = 1e-4
+
+
+class _TestRFFTBase:
+    def setup_method(self):
+        np.random.seed(1234)
+
+    def test_definition(self):
+        for t in [[1, 2, 3, 4, 1, 2, 3, 4], [1, 2, 3, 4, 1, 2, 3, 4, 5]]:
+            x = np.array(t, dtype=self.rdt)
+            y = rfft(x)
+            y1 = direct_rdft(x)
+            assert_array_almost_equal(y,y1)
+            assert_equal(y.dtype, self.cdt)
+
+    def test_djbfft(self):
+        for i in range(2,14):
+            n = 2**i
+            x = np.arange(n)
+            y1 = np.fft.rfft(x)
+            y = rfft(x)
+            assert_array_almost_equal(y,y1)
+
+    def test_invalid_sizes(self):
+        assert_raises(ValueError, rfft, [])
+        assert_raises(ValueError, rfft, [[1,1],[2,2]], -5)
+
+    def test_complex_input(self):
+        x = np.zeros(10, dtype=self.cdt)
+        with assert_raises(TypeError, match="x must be a real sequence"):
+            rfft(x)
+
+    # See gh-5790
+    class MockSeries:
+        def __init__(self, data):
+            self.data = np.asarray(data)
+
+        def __getattr__(self, item):
+            try:
+                return getattr(self.data, item)
+            except AttributeError as e:
+                raise AttributeError("'MockSeries' object "
+                                      f"has no attribute '{item}'") from e
+
+    def test_non_ndarray_with_dtype(self):
+        x = np.array([1., 2., 3., 4., 5.])
+        xs = _TestRFFTBase.MockSeries(x)
+
+        expected = [1, 2, 3, 4, 5]
+        rfft(xs)
+
+        # Data should not have been overwritten
+        assert_equal(x, expected)
+        assert_equal(xs.data, expected)
+
+@pytest.mark.skipif(np.longdouble is np.float64,
+                    reason="Long double is aliased to double")
+class TestRFFTLongDouble(_TestRFFTBase):
+    def setup_method(self):
+        self.cdt = np.clongdouble
+        self.rdt = np.longdouble
+
+
+class TestRFFTDouble(_TestRFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex128
+        self.rdt = np.float64
+
+
+class TestRFFTSingle(_TestRFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex64
+        self.rdt = np.float32
+
+
+class _TestIRFFTBase:
+    def setup_method(self):
+        np.random.seed(1234)
+
+    def test_definition(self):
+        x1 = [1,2+3j,4+1j,1+2j,3+4j]
+        x1_1 = [1,2+3j,4+1j,2+3j,4,2-3j,4-1j,2-3j]
+        x1 = x1_1[:5]
+        x2_1 = [1,2+3j,4+1j,2+3j,4+5j,4-5j,2-3j,4-1j,2-3j]
+        x2 = x2_1[:5]
+
+        def _test(x, xr):
+            y = irfft(np.array(x, dtype=self.cdt), n=len(xr))
+            y1 = direct_irdft(x, len(xr))
+            assert_equal(y.dtype, self.rdt)
+            assert_array_almost_equal(y,y1, decimal=self.ndec)
+            assert_array_almost_equal(y,ifft(xr), decimal=self.ndec)
+
+        _test(x1, x1_1)
+        _test(x2, x2_1)
+
+    def test_djbfft(self):
+        for i in range(2,14):
+            n = 2**i
+            x = np.arange(-1, n, 2) + 1j * np.arange(0, n+1, 2)
+            x[0] = 0
+            if n % 2 == 0:
+                x[-1] = np.real(x[-1])
+            y1 = np.fft.irfft(x)
+            y = irfft(x)
+            assert_array_almost_equal(y,y1)
+
+    def test_random_real(self):
+        for size in [1,51,111,100,200,64,128,256,1024]:
+            x = random([size]).astype(self.rdt)
+            y1 = irfft(rfft(x), n=size)
+            y2 = rfft(irfft(x, n=(size*2-1)))
+            assert_equal(y1.dtype, self.rdt)
+            assert_equal(y2.dtype, self.cdt)
+            assert_array_almost_equal(y1, x, decimal=self.ndec,
+                                       err_msg="size=%d" % size)
+            assert_array_almost_equal(y2, x, decimal=self.ndec,
+                                       err_msg="size=%d" % size)
+
+    def test_size_accuracy(self):
+        # Sanity check for the accuracy for prime and non-prime sized inputs
+        if self.rdt == np.float32:
+            rtol = 1e-5
+        elif self.rdt == np.float64:
+            rtol = 1e-10
+
+        for size in LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES:
+            np.random.seed(1234)
+            x = np.random.rand(size).astype(self.rdt)
+            y = irfft(rfft(x), len(x))
+            _assert_close_in_norm(x, y, rtol, size, self.rdt)
+            y = rfft(irfft(x, 2 * len(x) - 1))
+            _assert_close_in_norm(x, y, rtol, size, self.rdt)
+
+    def test_invalid_sizes(self):
+        assert_raises(ValueError, irfft, [])
+        assert_raises(ValueError, irfft, [[1,1],[2,2]], -5)
+
+
+# self.ndec is bogus; we should have a assert_array_approx_equal for number of
+# significant digits
+
+@pytest.mark.skipif(np.longdouble is np.float64,
+                    reason="Long double is aliased to double")
+class TestIRFFTLongDouble(_TestIRFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex128
+        self.rdt = np.float64
+        self.ndec = 14
+
+
+class TestIRFFTDouble(_TestIRFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex128
+        self.rdt = np.float64
+        self.ndec = 14
+
+
+class TestIRFFTSingle(_TestIRFFTBase):
+    def setup_method(self):
+        self.cdt = np.complex64
+        self.rdt = np.float32
+        self.ndec = 5
+
+
+class TestFftnSingle:
+    def setup_method(self):
+        np.random.seed(1234)
+
+    def test_definition(self):
+        x = [[1, 2, 3],
+             [4, 5, 6],
+             [7, 8, 9]]
+        y = fftn(np.array(x, np.float32))
+        assert_(y.dtype == np.complex64,
+                msg="double precision output with single precision")
+
+        y_r = np.array(fftn(x), np.complex64)
+        assert_array_almost_equal_nulp(y, y_r)
+
+    @pytest.mark.parametrize('size', SMALL_COMPOSITE_SIZES + SMALL_PRIME_SIZES)
+    def test_size_accuracy_small(self, size):
+        x = np.random.rand(size, size) + 1j*np.random.rand(size, size)
+        y1 = fftn(x.real.astype(np.float32))
+        y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
+
+        assert_equal(y1.dtype, np.complex64)
+        assert_array_almost_equal_nulp(y1, y2, 2000)
+
+    @pytest.mark.parametrize('size', LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES)
+    def test_size_accuracy_large(self, size):
+        x = np.random.rand(size, 3) + 1j*np.random.rand(size, 3)
+        y1 = fftn(x.real.astype(np.float32))
+        y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
+
+        assert_equal(y1.dtype, np.complex64)
+        assert_array_almost_equal_nulp(y1, y2, 2000)
+
+    def test_definition_float16(self):
+        x = [[1, 2, 3],
+             [4, 5, 6],
+             [7, 8, 9]]
+        y = fftn(np.array(x, np.float16))
+        assert_equal(y.dtype, np.complex64)
+        y_r = np.array(fftn(x), np.complex64)
+        assert_array_almost_equal_nulp(y, y_r)
+
+    @pytest.mark.parametrize('size', SMALL_COMPOSITE_SIZES + SMALL_PRIME_SIZES)
+    def test_float16_input_small(self, size):
+        x = np.random.rand(size, size) + 1j*np.random.rand(size, size)
+        y1 = fftn(x.real.astype(np.float16))
+        y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
+
+        assert_equal(y1.dtype, np.complex64)
+        assert_array_almost_equal_nulp(y1, y2, 5e5)
+
+    @pytest.mark.parametrize('size', LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES)
+    def test_float16_input_large(self, size):
+        x = np.random.rand(size, 3) + 1j*np.random.rand(size, 3)
+        y1 = fftn(x.real.astype(np.float16))
+        y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
+
+        assert_equal(y1.dtype, np.complex64)
+        assert_array_almost_equal_nulp(y1, y2, 2e6)
+
+
+class TestFftn:
+    def setup_method(self):
+        np.random.seed(1234)
+
+    def test_definition(self):
+        x = [[1, 2, 3],
+             [4, 5, 6],
+             [7, 8, 9]]
+        y = fftn(x)
+        assert_array_almost_equal(y, direct_dftn(x))
+
+        x = random((20, 26))
+        assert_array_almost_equal(fftn(x), direct_dftn(x))
+
+        x = random((5, 4, 3, 20))
+        assert_array_almost_equal(fftn(x), direct_dftn(x))
+
+    def test_axes_argument(self):
+        # plane == ji_plane, x== kji_space
+        plane1 = [[1, 2, 3],
+                  [4, 5, 6],
+                  [7, 8, 9]]
+        plane2 = [[10, 11, 12],
+                  [13, 14, 15],
+                  [16, 17, 18]]
+        plane3 = [[19, 20, 21],
+                  [22, 23, 24],
+                  [25, 26, 27]]
+        ki_plane1 = [[1, 2, 3],
+                     [10, 11, 12],
+                     [19, 20, 21]]
+        ki_plane2 = [[4, 5, 6],
+                     [13, 14, 15],
+                     [22, 23, 24]]
+        ki_plane3 = [[7, 8, 9],
+                     [16, 17, 18],
+                     [25, 26, 27]]
+        jk_plane1 = [[1, 10, 19],
+                     [4, 13, 22],
+                     [7, 16, 25]]
+        jk_plane2 = [[2, 11, 20],
+                     [5, 14, 23],
+                     [8, 17, 26]]
+        jk_plane3 = [[3, 12, 21],
+                     [6, 15, 24],
+                     [9, 18, 27]]
+        kj_plane1 = [[1, 4, 7],
+                     [10, 13, 16], [19, 22, 25]]
+        kj_plane2 = [[2, 5, 8],
+                     [11, 14, 17], [20, 23, 26]]
+        kj_plane3 = [[3, 6, 9],
+                     [12, 15, 18], [21, 24, 27]]
+        ij_plane1 = [[1, 4, 7],
+                     [2, 5, 8],
+                     [3, 6, 9]]
+        ij_plane2 = [[10, 13, 16],
+                     [11, 14, 17],
+                     [12, 15, 18]]
+        ij_plane3 = [[19, 22, 25],
+                     [20, 23, 26],
+                     [21, 24, 27]]
+        ik_plane1 = [[1, 10, 19],
+                     [2, 11, 20],
+                     [3, 12, 21]]
+        ik_plane2 = [[4, 13, 22],
+                     [5, 14, 23],
+                     [6, 15, 24]]
+        ik_plane3 = [[7, 16, 25],
+                     [8, 17, 26],
+                     [9, 18, 27]]
+        ijk_space = [jk_plane1, jk_plane2, jk_plane3]
+        ikj_space = [kj_plane1, kj_plane2, kj_plane3]
+        jik_space = [ik_plane1, ik_plane2, ik_plane3]
+        jki_space = [ki_plane1, ki_plane2, ki_plane3]
+        kij_space = [ij_plane1, ij_plane2, ij_plane3]
+        x = array([plane1, plane2, plane3])
+
+        assert_array_almost_equal(fftn(x),
+                                  fftn(x, axes=(-3, -2, -1)))  # kji_space
+        assert_array_almost_equal(fftn(x), fftn(x, axes=(0, 1, 2)))
+        assert_array_almost_equal(fftn(x, axes=(0, 2)), fftn(x, axes=(0, -1)))
+        y = fftn(x, axes=(2, 1, 0))  # ijk_space
+        assert_array_almost_equal(swapaxes(y, -1, -3), fftn(ijk_space))
+        y = fftn(x, axes=(2, 0, 1))  # ikj_space
+        assert_array_almost_equal(swapaxes(swapaxes(y, -1, -3), -1, -2),
+                                  fftn(ikj_space))
+        y = fftn(x, axes=(1, 2, 0))  # jik_space
+        assert_array_almost_equal(swapaxes(swapaxes(y, -1, -3), -3, -2),
+                                  fftn(jik_space))
+        y = fftn(x, axes=(1, 0, 2))  # jki_space
+        assert_array_almost_equal(swapaxes(y, -2, -3), fftn(jki_space))
+        y = fftn(x, axes=(0, 2, 1))  # kij_space
+        assert_array_almost_equal(swapaxes(y, -2, -1), fftn(kij_space))
+
+        y = fftn(x, axes=(-2, -1))  # ji_plane
+        assert_array_almost_equal(fftn(plane1), y[0])
+        assert_array_almost_equal(fftn(plane2), y[1])
+        assert_array_almost_equal(fftn(plane3), y[2])
+
+        y = fftn(x, axes=(1, 2))  # ji_plane
+        assert_array_almost_equal(fftn(plane1), y[0])
+        assert_array_almost_equal(fftn(plane2), y[1])
+        assert_array_almost_equal(fftn(plane3), y[2])
+
+        y = fftn(x, axes=(-3, -2))  # kj_plane
+        assert_array_almost_equal(fftn(x[:, :, 0]), y[:, :, 0])
+        assert_array_almost_equal(fftn(x[:, :, 1]), y[:, :, 1])
+        assert_array_almost_equal(fftn(x[:, :, 2]), y[:, :, 2])
+
+        y = fftn(x, axes=(-3, -1))  # ki_plane
+        assert_array_almost_equal(fftn(x[:, 0, :]), y[:, 0, :])
+        assert_array_almost_equal(fftn(x[:, 1, :]), y[:, 1, :])
+        assert_array_almost_equal(fftn(x[:, 2, :]), y[:, 2, :])
+
+        y = fftn(x, axes=(-1, -2))  # ij_plane
+        assert_array_almost_equal(fftn(ij_plane1), swapaxes(y[0], -2, -1))
+        assert_array_almost_equal(fftn(ij_plane2), swapaxes(y[1], -2, -1))
+        assert_array_almost_equal(fftn(ij_plane3), swapaxes(y[2], -2, -1))
+
+        y = fftn(x, axes=(-1, -3))  # ik_plane
+        assert_array_almost_equal(fftn(ik_plane1),
+                                  swapaxes(y[:, 0, :], -1, -2))
+        assert_array_almost_equal(fftn(ik_plane2),
+                                  swapaxes(y[:, 1, :], -1, -2))
+        assert_array_almost_equal(fftn(ik_plane3),
+                                  swapaxes(y[:, 2, :], -1, -2))
+
+        y = fftn(x, axes=(-2, -3))  # jk_plane
+        assert_array_almost_equal(fftn(jk_plane1),
+                                  swapaxes(y[:, :, 0], -1, -2))
+        assert_array_almost_equal(fftn(jk_plane2),
+                                  swapaxes(y[:, :, 1], -1, -2))
+        assert_array_almost_equal(fftn(jk_plane3),
+                                  swapaxes(y[:, :, 2], -1, -2))
+
+        y = fftn(x, axes=(-1,))  # i_line
+        for i in range(3):
+            for j in range(3):
+                assert_array_almost_equal(fft(x[i, j, :]), y[i, j, :])
+        y = fftn(x, axes=(-2,))  # j_line
+        for i in range(3):
+            for j in range(3):
+                assert_array_almost_equal(fft(x[i, :, j]), y[i, :, j])
+        y = fftn(x, axes=(0,))  # k_line
+        for i in range(3):
+            for j in range(3):
+                assert_array_almost_equal(fft(x[:, i, j]), y[:, i, j])
+
+        y = fftn(x, axes=())  # point
+        assert_array_almost_equal(y, x)
+
+    def test_shape_argument(self):
+        small_x = [[1, 2, 3],
+                   [4, 5, 6]]
+        large_x1 = [[1, 2, 3, 0],
+                    [4, 5, 6, 0],
+                    [0, 0, 0, 0],
+                    [0, 0, 0, 0]]
+
+        y = fftn(small_x, s=(4, 4))
+        assert_array_almost_equal(y, fftn(large_x1))
+
+        y = fftn(small_x, s=(3, 4))
+        assert_array_almost_equal(y, fftn(large_x1[:-1]))
+
+    def test_shape_axes_argument(self):
+        small_x = [[1, 2, 3],
+                   [4, 5, 6],
+                   [7, 8, 9]]
+        large_x1 = array([[1, 2, 3, 0],
+                          [4, 5, 6, 0],
+                          [7, 8, 9, 0],
+                          [0, 0, 0, 0]])
+        y = fftn(small_x, s=(4, 4), axes=(-2, -1))
+        assert_array_almost_equal(y, fftn(large_x1))
+        y = fftn(small_x, s=(4, 4), axes=(-1, -2))
+
+        assert_array_almost_equal(y, swapaxes(
+            fftn(swapaxes(large_x1, -1, -2)), -1, -2))
+
+    def test_shape_axes_argument2(self):
+        # Change shape of the last axis
+        x = numpy.random.random((10, 5, 3, 7))
+        y = fftn(x, axes=(-1,), s=(8,))
+        assert_array_almost_equal(y, fft(x, axis=-1, n=8))
+
+        # Change shape of an arbitrary axis which is not the last one
+        x = numpy.random.random((10, 5, 3, 7))
+        y = fftn(x, axes=(-2,), s=(8,))
+        assert_array_almost_equal(y, fft(x, axis=-2, n=8))
+
+        # Change shape of axes: cf #244, where shape and axes were mixed up
+        x = numpy.random.random((4, 4, 2))
+        y = fftn(x, axes=(-3, -2), s=(8, 8))
+        assert_array_almost_equal(y,
+                                  numpy.fft.fftn(x, axes=(-3, -2), s=(8, 8)))
+
+    def test_shape_argument_more(self):
+        x = zeros((4, 4, 2))
+        with assert_raises(ValueError,
+                           match="shape requires more axes than are present"):
+            fftn(x, s=(8, 8, 2, 1))
+
+    def test_invalid_sizes(self):
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[1, 0\]\) specified"):
+            fftn([[]])
+
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[4, -3\]\) specified"):
+            fftn([[1, 1], [2, 2]], (4, -3))
+
+    def test_no_axes(self):
+        x = numpy.random.random((2,2,2))
+        assert_allclose(fftn(x, axes=[]), x, atol=1e-7)
+
+    def test_regression_244(self):
+        """FFT returns wrong result with axes parameter."""
+        # fftn (and hence fft2) used to break when both axes and shape were used
+        x = numpy.ones((4, 4, 2))
+        y = fftn(x, s=(8, 8), axes=(-3, -2))
+        y_r = numpy.fft.fftn(x, s=(8, 8), axes=(-3, -2))
+        assert_allclose(y, y_r)
+
+
+class TestIfftn:
+    dtype = None
+    cdtype = None
+
+    def setup_method(self):
+        np.random.seed(1234)
+
+    @pytest.mark.parametrize('dtype,cdtype,maxnlp',
+                             [(np.float64, np.complex128, 2000),
+                              (np.float32, np.complex64, 3500)])
+    def test_definition(self, dtype, cdtype, maxnlp):
+        x = np.array([[1, 2, 3],
+                      [4, 5, 6],
+                      [7, 8, 9]], dtype=dtype)
+        y = ifftn(x)
+        assert_equal(y.dtype, cdtype)
+        assert_array_almost_equal_nulp(y, direct_idftn(x), maxnlp)
+
+        x = random((20, 26))
+        assert_array_almost_equal_nulp(ifftn(x), direct_idftn(x), maxnlp)
+
+        x = random((5, 4, 3, 20))
+        assert_array_almost_equal_nulp(ifftn(x), direct_idftn(x), maxnlp)
+
+    @pytest.mark.parametrize('maxnlp', [2000, 3500])
+    @pytest.mark.parametrize('size', [1, 2, 51, 32, 64, 92])
+    def test_random_complex(self, maxnlp, size):
+        x = random([size, size]) + 1j*random([size, size])
+        assert_array_almost_equal_nulp(ifftn(fftn(x)), x, maxnlp)
+        assert_array_almost_equal_nulp(fftn(ifftn(x)), x, maxnlp)
+
+    def test_invalid_sizes(self):
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[1, 0\]\) specified"):
+            ifftn([[]])
+
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[4, -3\]\) specified"):
+            ifftn([[1, 1], [2, 2]], (4, -3))
+
+    def test_no_axes(self):
+        x = numpy.random.random((2,2,2))
+        assert_allclose(ifftn(x, axes=[]), x, atol=1e-7)
+
+class TestRfftn:
+    dtype = None
+    cdtype = None
+
+    def setup_method(self):
+        np.random.seed(1234)
+
+    @pytest.mark.parametrize('dtype,cdtype,maxnlp',
+                             [(np.float64, np.complex128, 2000),
+                              (np.float32, np.complex64, 3500)])
+    def test_definition(self, dtype, cdtype, maxnlp):
+        x = np.array([[1, 2, 3],
+                      [4, 5, 6],
+                      [7, 8, 9]], dtype=dtype)
+        y = rfftn(x)
+        assert_equal(y.dtype, cdtype)
+        assert_array_almost_equal_nulp(y, direct_rdftn(x), maxnlp)
+
+        x = random((20, 26))
+        assert_array_almost_equal_nulp(rfftn(x), direct_rdftn(x), maxnlp)
+
+        x = random((5, 4, 3, 20))
+        assert_array_almost_equal_nulp(rfftn(x), direct_rdftn(x), maxnlp)
+
+    @pytest.mark.parametrize('size', [1, 2, 51, 32, 64, 92])
+    def test_random(self, size):
+        x = random([size, size])
+        assert_allclose(irfftn(rfftn(x), x.shape), x, atol=1e-10)
+
+    @pytest.mark.parametrize('func', [rfftn, irfftn])
+    def test_invalid_sizes(self, func):
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[1, 0\]\) specified"):
+            func([[]])
+
+        with assert_raises(ValueError,
+                           match="invalid number of data points"
+                           r" \(\[4, -3\]\) specified"):
+            func([[1, 1], [2, 2]], (4, -3))
+
+    @pytest.mark.parametrize('func', [rfftn, irfftn])
+    def test_no_axes(self, func):
+        with assert_raises(ValueError,
+                           match="at least 1 axis must be transformed"):
+            func([], axes=[])
+
+    def test_complex_input(self):
+        with assert_raises(TypeError, match="x must be a real sequence"):
+            rfftn(np.zeros(10, dtype=np.complex64))
+
+
+class FakeArray:
+    def __init__(self, data):
+        self._data = data
+        self.__array_interface__ = data.__array_interface__
+
+
+class FakeArray2:
+    def __init__(self, data):
+        self._data = data
+
+    def __array__(self, dtype=None, copy=None):
+        return self._data
+
+# TODO: Is this test actually valuable? The behavior it's testing shouldn't be
+# relied upon by users except for overwrite_x = False
+class TestOverwrite:
+    """Check input overwrite behavior of the FFT functions."""
+
+    real_dtypes = [np.float32, np.float64, np.longdouble]
+    dtypes = real_dtypes + [np.complex64, np.complex128, np.clongdouble]
+    fftsizes = [8, 16, 32]
+
+    def _check(self, x, routine, fftsize, axis, overwrite_x, should_overwrite):
+        x2 = x.copy()
+        for fake in [lambda x: x, FakeArray, FakeArray2]:
+            routine(fake(x2), fftsize, axis, overwrite_x=overwrite_x)
+
+            sig = "{}({}{!r}, {!r}, axis={!r}, overwrite_x={!r})".format(
+                routine.__name__, x.dtype, x.shape, fftsize, axis, overwrite_x)
+            if not should_overwrite:
+                assert_equal(x2, x, err_msg="spurious overwrite in %s" % sig)
+
+    def _check_1d(self, routine, dtype, shape, axis, overwritable_dtypes,
+                  fftsize, overwrite_x):
+        np.random.seed(1234)
+        if np.issubdtype(dtype, np.complexfloating):
+            data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
+        else:
+            data = np.random.randn(*shape)
+        data = data.astype(dtype)
+
+        should_overwrite = (overwrite_x
+                            and dtype in overwritable_dtypes
+                            and fftsize <= shape[axis])
+        self._check(data, routine, fftsize, axis,
+                    overwrite_x=overwrite_x,
+                    should_overwrite=should_overwrite)
+
+    @pytest.mark.parametrize('dtype', dtypes)
+    @pytest.mark.parametrize('fftsize', fftsizes)
+    @pytest.mark.parametrize('overwrite_x', [True, False])
+    @pytest.mark.parametrize('shape,axes', [((16,), -1),
+                                            ((16, 2), 0),
+                                            ((2, 16), 1)])
+    def test_fft_ifft(self, dtype, fftsize, overwrite_x, shape, axes):
+        overwritable = (np.clongdouble, np.complex128, np.complex64)
+        self._check_1d(fft, dtype, shape, axes, overwritable,
+                       fftsize, overwrite_x)
+        self._check_1d(ifft, dtype, shape, axes, overwritable,
+                       fftsize, overwrite_x)
+
+    @pytest.mark.parametrize('dtype', real_dtypes)
+    @pytest.mark.parametrize('fftsize', fftsizes)
+    @pytest.mark.parametrize('overwrite_x', [True, False])
+    @pytest.mark.parametrize('shape,axes', [((16,), -1),
+                                            ((16, 2), 0),
+                                            ((2, 16), 1)])
+    def test_rfft_irfft(self, dtype, fftsize, overwrite_x, shape, axes):
+        overwritable = self.real_dtypes
+        self._check_1d(irfft, dtype, shape, axes, overwritable,
+                       fftsize, overwrite_x)
+        self._check_1d(rfft, dtype, shape, axes, overwritable,
+                       fftsize, overwrite_x)
+
+    def _check_nd_one(self, routine, dtype, shape, axes, overwritable_dtypes,
+                      overwrite_x):
+        np.random.seed(1234)
+        if np.issubdtype(dtype, np.complexfloating):
+            data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
+        else:
+            data = np.random.randn(*shape)
+        data = data.astype(dtype)
+
+        def fftshape_iter(shp):
+            if len(shp) <= 0:
+                yield ()
+            else:
+                for j in (shp[0]//2, shp[0], shp[0]*2):
+                    for rest in fftshape_iter(shp[1:]):
+                        yield (j,) + rest
+
+        def part_shape(shape, axes):
+            if axes is None:
+                return shape
+            else:
+                return tuple(np.take(shape, axes))
+
+        def should_overwrite(data, shape, axes):
+            s = part_shape(data.shape, axes)
+            return (overwrite_x and
+                    np.prod(shape) <= np.prod(s)
+                    and dtype in overwritable_dtypes)
+
+        for fftshape in fftshape_iter(part_shape(shape, axes)):
+            self._check(data, routine, fftshape, axes,
+                        overwrite_x=overwrite_x,
+                        should_overwrite=should_overwrite(data, fftshape, axes))
+            if data.ndim > 1:
+                # check fortran order
+                self._check(data.T, routine, fftshape, axes,
+                            overwrite_x=overwrite_x,
+                            should_overwrite=should_overwrite(
+                                data.T, fftshape, axes))
+
+    @pytest.mark.parametrize('dtype', dtypes)
+    @pytest.mark.parametrize('overwrite_x', [True, False])
+    @pytest.mark.parametrize('shape,axes', [((16,), None),
+                                            ((16,), (0,)),
+                                            ((16, 2), (0,)),
+                                            ((2, 16), (1,)),
+                                            ((8, 16), None),
+                                            ((8, 16), (0, 1)),
+                                            ((8, 16, 2), (0, 1)),
+                                            ((8, 16, 2), (1, 2)),
+                                            ((8, 16, 2), (0,)),
+                                            ((8, 16, 2), (1,)),
+                                            ((8, 16, 2), (2,)),
+                                            ((8, 16, 2), None),
+                                            ((8, 16, 2), (0, 1, 2))])
+    def test_fftn_ifftn(self, dtype, overwrite_x, shape, axes):
+        overwritable = (np.clongdouble, np.complex128, np.complex64)
+        self._check_nd_one(fftn, dtype, shape, axes, overwritable,
+                           overwrite_x)
+        self._check_nd_one(ifftn, dtype, shape, axes, overwritable,
+                           overwrite_x)
+
+
+@pytest.mark.parametrize('func', [fft, ifft, fftn, ifftn,
+                                 rfft, irfft, rfftn, irfftn])
+def test_invalid_norm(func):
+    x = np.arange(10, dtype=float)
+    with assert_raises(ValueError,
+                       match='Invalid norm value \'o\', should be'
+                             ' "backward", "ortho" or "forward"'):
+        func(x, norm='o')
+
+
+@pytest.mark.parametrize('func', [fft, ifft, fftn, ifftn,
+                                   irfft, irfftn, hfft, hfftn])
+def test_swapped_byte_order_complex(func):
+    rng = np.random.RandomState(1234)
+    x = rng.rand(10) + 1j * rng.rand(10)
+    assert_allclose(func(swap_byteorder(x)), func(x))
+
+
+@pytest.mark.parametrize('func', [ihfft, ihfftn, rfft, rfftn])
+def test_swapped_byte_order_real(func):
+    rng = np.random.RandomState(1234)
+    x = rng.rand(10)
+    assert_allclose(func(swap_byteorder(x)), func(x))

venv/lib/python3.10/site-packages/scipy/fft/_pocketfft/tests/test_real_transforms.py

@@ -0,0 +1,494 @@
+from os.path import join, dirname
+from typing import Callable, Union
+
+import numpy as np
+from numpy.testing import (
+    assert_array_almost_equal, assert_equal, assert_allclose)
+import pytest
+from pytest import raises as assert_raises
+
+from scipy.fft._pocketfft.realtransforms import (
+    dct, idct, dst, idst, dctn, idctn, dstn, idstn)
+
+fftpack_test_dir = join(dirname(__file__), '..', '..', '..', 'fftpack', 'tests')
+
+MDATA_COUNT = 8
+FFTWDATA_COUNT = 14
+
+def is_longdouble_binary_compatible():
+    try:
+        one = np.frombuffer(
+            b'\x00\x00\x00\x00\x00\x00\x00\x80\xff\x3f\x00\x00\x00\x00\x00\x00',
+            dtype='<f16')
+        return one == np.longdouble(1.)
+    except TypeError:
+        return False
+
+
+@pytest.fixture(scope="module")
+def reference_data():
+    # Matlab reference data
+    MDATA = np.load(join(fftpack_test_dir, 'test.npz'))
+    X = [MDATA['x%d' % i] for i in range(MDATA_COUNT)]
+    Y = [MDATA['y%d' % i] for i in range(MDATA_COUNT)]
+
+    # FFTW reference data: the data are organized as follows:
+    #    * SIZES is an array containing all available sizes
+    #    * for every type (1, 2, 3, 4) and every size, the array dct_type_size
+    #    contains the output of the DCT applied to the input np.linspace(0, size-1,
+    #    size)
+    FFTWDATA_DOUBLE = np.load(join(fftpack_test_dir, 'fftw_double_ref.npz'))
+    FFTWDATA_SINGLE = np.load(join(fftpack_test_dir, 'fftw_single_ref.npz'))
+    FFTWDATA_SIZES = FFTWDATA_DOUBLE['sizes']
+    assert len(FFTWDATA_SIZES) == FFTWDATA_COUNT
+
+    if is_longdouble_binary_compatible():
+        FFTWDATA_LONGDOUBLE = np.load(
+            join(fftpack_test_dir, 'fftw_longdouble_ref.npz'))
+    else:
+        FFTWDATA_LONGDOUBLE = {k: v.astype(np.longdouble)
+                               for k,v in FFTWDATA_DOUBLE.items()}
+
+    ref = {
+        'FFTWDATA_LONGDOUBLE': FFTWDATA_LONGDOUBLE,
+        'FFTWDATA_DOUBLE': FFTWDATA_DOUBLE,
+        'FFTWDATA_SINGLE': FFTWDATA_SINGLE,
+        'FFTWDATA_SIZES': FFTWDATA_SIZES,
+        'X': X,
+        'Y': Y
+    }
+
+    yield ref
+
+    if is_longdouble_binary_compatible():
+        FFTWDATA_LONGDOUBLE.close()
+    FFTWDATA_SINGLE.close()
+    FFTWDATA_DOUBLE.close()
+    MDATA.close()
+
+
+@pytest.fixture(params=range(FFTWDATA_COUNT))
+def fftwdata_size(request, reference_data):
+    return reference_data['FFTWDATA_SIZES'][request.param]
+
+@pytest.fixture(params=range(MDATA_COUNT))
+def mdata_x(request, reference_data):
+    return reference_data['X'][request.param]
+
+
+@pytest.fixture(params=range(MDATA_COUNT))
+def mdata_xy(request, reference_data):
+    y = reference_data['Y'][request.param]
+    x = reference_data['X'][request.param]
+    return x, y
+
+
+def fftw_dct_ref(type, size, dt, reference_data):
+    x = np.linspace(0, size-1, size).astype(dt)
+    dt = np.result_type(np.float32, dt)
+    if dt == np.float64:
+        data = reference_data['FFTWDATA_DOUBLE']
+    elif dt == np.float32:
+        data = reference_data['FFTWDATA_SINGLE']
+    elif dt == np.longdouble:
+        data = reference_data['FFTWDATA_LONGDOUBLE']
+    else:
+        raise ValueError()
+    y = (data['dct_%d_%d' % (type, size)]).astype(dt)
+    return x, y, dt
+
+
+def fftw_dst_ref(type, size, dt, reference_data):
+    x = np.linspace(0, size-1, size).astype(dt)
+    dt = np.result_type(np.float32, dt)
+    if dt == np.float64:
+        data = reference_data['FFTWDATA_DOUBLE']
+    elif dt == np.float32:
+        data = reference_data['FFTWDATA_SINGLE']
+    elif dt == np.longdouble:
+        data = reference_data['FFTWDATA_LONGDOUBLE']
+    else:
+        raise ValueError()
+    y = (data['dst_%d_%d' % (type, size)]).astype(dt)
+    return x, y, dt
+
+
+def ref_2d(func, x, **kwargs):
+    """Calculate 2-D reference data from a 1d transform"""
+    x = np.array(x, copy=True)
+    for row in range(x.shape[0]):
+        x[row, :] = func(x[row, :], **kwargs)
+    for col in range(x.shape[1]):
+        x[:, col] = func(x[:, col], **kwargs)
+    return x
+
+
+def naive_dct1(x, norm=None):
+    """Calculate textbook definition version of DCT-I."""
+    x = np.array(x, copy=True)
+    N = len(x)
+    M = N-1
+    y = np.zeros(N)
+    m0, m = 1, 2
+    if norm == 'ortho':
+        m0 = np.sqrt(1.0/M)
+        m = np.sqrt(2.0/M)
+    for k in range(N):
+        for n in range(1, N-1):
+            y[k] += m*x[n]*np.cos(np.pi*n*k/M)
+        y[k] += m0 * x[0]
+        y[k] += m0 * x[N-1] * (1 if k % 2 == 0 else -1)
+    if norm == 'ortho':
+        y[0] *= 1/np.sqrt(2)
+        y[N-1] *= 1/np.sqrt(2)
+    return y
+
+
+def naive_dst1(x, norm=None):
+    """Calculate textbook definition version of DST-I."""
+    x = np.array(x, copy=True)
+    N = len(x)
+    M = N+1
+    y = np.zeros(N)
+    for k in range(N):
+        for n in range(N):
+            y[k] += 2*x[n]*np.sin(np.pi*(n+1.0)*(k+1.0)/M)
+    if norm == 'ortho':
+        y *= np.sqrt(0.5/M)
+    return y
+
+
+def naive_dct4(x, norm=None):
+    """Calculate textbook definition version of DCT-IV."""
+    x = np.array(x, copy=True)
+    N = len(x)
+    y = np.zeros(N)
+    for k in range(N):
+        for n in range(N):
+            y[k] += x[n]*np.cos(np.pi*(n+0.5)*(k+0.5)/(N))
+    if norm == 'ortho':
+        y *= np.sqrt(2.0/N)
+    else:
+        y *= 2
+    return y
+
+
+def naive_dst4(x, norm=None):
+    """Calculate textbook definition version of DST-IV."""
+    x = np.array(x, copy=True)
+    N = len(x)
+    y = np.zeros(N)
+    for k in range(N):
+        for n in range(N):
+            y[k] += x[n]*np.sin(np.pi*(n+0.5)*(k+0.5)/(N))
+    if norm == 'ortho':
+        y *= np.sqrt(2.0/N)
+    else:
+        y *= 2
+    return y
+
+
+@pytest.mark.parametrize('dtype', [np.complex64, np.complex128, np.clongdouble])
+@pytest.mark.parametrize('transform', [dct, dst, idct, idst])
+def test_complex(transform, dtype):
+    y = transform(1j*np.arange(5, dtype=dtype))
+    x = 1j*transform(np.arange(5))
+    assert_array_almost_equal(x, y)
+
+
+DecMapType = dict[
+    tuple[Callable[..., np.ndarray], Union[type[np.floating], type[int]], int],
+    int,
+]
+
+# map (transform, dtype, type) -> decimal
+dec_map: DecMapType = {
+    # DCT
+    (dct, np.float64, 1): 13,
+    (dct, np.float32, 1): 6,
+
+    (dct, np.float64, 2): 14,
+    (dct, np.float32, 2): 5,
+
+    (dct, np.float64, 3): 14,
+    (dct, np.float32, 3): 5,
+
+    (dct, np.float64, 4): 13,
+    (dct, np.float32, 4): 6,
+
+    # IDCT
+    (idct, np.float64, 1): 14,
+    (idct, np.float32, 1): 6,
+
+    (idct, np.float64, 2): 14,
+    (idct, np.float32, 2): 5,
+
+    (idct, np.float64, 3): 14,
+    (idct, np.float32, 3): 5,
+
+    (idct, np.float64, 4): 14,
+    (idct, np.float32, 4): 6,
+
+    # DST
+    (dst, np.float64, 1): 13,
+    (dst, np.float32, 1): 6,
+
+    (dst, np.float64, 2): 14,
+    (dst, np.float32, 2): 6,
+
+    (dst, np.float64, 3): 14,
+    (dst, np.float32, 3): 7,
+
+    (dst, np.float64, 4): 13,
+    (dst, np.float32, 4): 5,
+
+    # IDST
+    (idst, np.float64, 1): 14,
+    (idst, np.float32, 1): 6,
+
+    (idst, np.float64, 2): 14,
+    (idst, np.float32, 2): 6,
+
+    (idst, np.float64, 3): 14,
+    (idst, np.float32, 3): 6,
+
+    (idst, np.float64, 4): 14,
+    (idst, np.float32, 4): 6,
+}
+
+for k,v in dec_map.copy().items():
+    if k[1] == np.float64:
+        dec_map[(k[0], np.longdouble, k[2])] = v
+    elif k[1] == np.float32:
+        dec_map[(k[0], int, k[2])] = v
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+@pytest.mark.parametrize('type', [1, 2, 3, 4])
+class TestDCT:
+    def test_definition(self, rdt, type, fftwdata_size, reference_data):
+        x, yr, dt = fftw_dct_ref(type, fftwdata_size, rdt, reference_data)
+        y = dct(x, type=type)
+        assert_equal(y.dtype, dt)
+        dec = dec_map[(dct, rdt, type)]
+        assert_allclose(y, yr, rtol=0., atol=np.max(yr)*10**(-dec))
+
+    @pytest.mark.parametrize('size', [7, 8, 9, 16, 32, 64])
+    def test_axis(self, rdt, type, size):
+        nt = 2
+        dec = dec_map[(dct, rdt, type)]
+        x = np.random.randn(nt, size)
+        y = dct(x, type=type)
+        for j in range(nt):
+            assert_array_almost_equal(y[j], dct(x[j], type=type),
+                                      decimal=dec)
+
+        x = x.T
+        y = dct(x, axis=0, type=type)
+        for j in range(nt):
+            assert_array_almost_equal(y[:,j], dct(x[:,j], type=type),
+                                      decimal=dec)
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dct1_definition_ortho(rdt, mdata_x):
+    # Test orthornomal mode.
+    dec = dec_map[(dct, rdt, 1)]
+    x = np.array(mdata_x, dtype=rdt)
+    dt = np.result_type(np.float32, rdt)
+    y = dct(x, norm='ortho', type=1)
+    y2 = naive_dct1(x, norm='ortho')
+    assert_equal(y.dtype, dt)
+    assert_allclose(y, y2, rtol=0., atol=np.max(y2)*10**(-dec))
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dct2_definition_matlab(mdata_xy, rdt):
+    # Test correspondence with matlab (orthornomal mode).
+    dt = np.result_type(np.float32, rdt)
+    x = np.array(mdata_xy[0], dtype=dt)
+
+    yr = mdata_xy[1]
+    y = dct(x, norm="ortho", type=2)
+    dec = dec_map[(dct, rdt, 2)]
+    assert_equal(y.dtype, dt)
+    assert_array_almost_equal(y, yr, decimal=dec)
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dct3_definition_ortho(mdata_x, rdt):
+    # Test orthornomal mode.
+    x = np.array(mdata_x, dtype=rdt)
+    dt = np.result_type(np.float32, rdt)
+    y = dct(x, norm='ortho', type=2)
+    xi = dct(y, norm="ortho", type=3)
+    dec = dec_map[(dct, rdt, 3)]
+    assert_equal(xi.dtype, dt)
+    assert_array_almost_equal(xi, x, decimal=dec)
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dct4_definition_ortho(mdata_x, rdt):
+    # Test orthornomal mode.
+    x = np.array(mdata_x, dtype=rdt)
+    dt = np.result_type(np.float32, rdt)
+    y = dct(x, norm='ortho', type=4)
+    y2 = naive_dct4(x, norm='ortho')
+    dec = dec_map[(dct, rdt, 4)]
+    assert_equal(y.dtype, dt)
+    assert_allclose(y, y2, rtol=0., atol=np.max(y2)*10**(-dec))
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+@pytest.mark.parametrize('type', [1, 2, 3, 4])
+def test_idct_definition(fftwdata_size, rdt, type, reference_data):
+    xr, yr, dt = fftw_dct_ref(type, fftwdata_size, rdt, reference_data)
+    x = idct(yr, type=type)
+    dec = dec_map[(idct, rdt, type)]
+    assert_equal(x.dtype, dt)
+    assert_allclose(x, xr, rtol=0., atol=np.max(xr)*10**(-dec))
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+@pytest.mark.parametrize('type', [1, 2, 3, 4])
+def test_definition(fftwdata_size, rdt, type, reference_data):
+    xr, yr, dt = fftw_dst_ref(type, fftwdata_size, rdt, reference_data)
+    y = dst(xr, type=type)
+    dec = dec_map[(dst, rdt, type)]
+    assert_equal(y.dtype, dt)
+    assert_allclose(y, yr, rtol=0., atol=np.max(yr)*10**(-dec))
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dst1_definition_ortho(rdt, mdata_x):
+    # Test orthornomal mode.
+    dec = dec_map[(dst, rdt, 1)]
+    x = np.array(mdata_x, dtype=rdt)
+    dt = np.result_type(np.float32, rdt)
+    y = dst(x, norm='ortho', type=1)
+    y2 = naive_dst1(x, norm='ortho')
+    assert_equal(y.dtype, dt)
+    assert_allclose(y, y2, rtol=0., atol=np.max(y2)*10**(-dec))
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+def test_dst4_definition_ortho(rdt, mdata_x):
+    # Test orthornomal mode.
+    dec = dec_map[(dst, rdt, 4)]
+    x = np.array(mdata_x, dtype=rdt)
+    dt = np.result_type(np.float32, rdt)
+    y = dst(x, norm='ortho', type=4)
+    y2 = naive_dst4(x, norm='ortho')
+    assert_equal(y.dtype, dt)
+    assert_array_almost_equal(y, y2, decimal=dec)
+
+
+@pytest.mark.parametrize('rdt', [np.longdouble, np.float64, np.float32, int])
+@pytest.mark.parametrize('type', [1, 2, 3, 4])
+def test_idst_definition(fftwdata_size, rdt, type, reference_data):
+    xr, yr, dt = fftw_dst_ref(type, fftwdata_size, rdt, reference_data)
+    x = idst(yr, type=type)
+    dec = dec_map[(idst, rdt, type)]
+    assert_equal(x.dtype, dt)
+    assert_allclose(x, xr, rtol=0., atol=np.max(xr)*10**(-dec))
+
+
+@pytest.mark.parametrize('routine', [dct, dst, idct, idst])
+@pytest.mark.parametrize('dtype', [np.float32, np.float64, np.longdouble])
+@pytest.mark.parametrize('shape, axis', [
+    ((16,), -1), ((16, 2), 0), ((2, 16), 1)
+])
+@pytest.mark.parametrize('type', [1, 2, 3, 4])
+@pytest.mark.parametrize('overwrite_x', [True, False])
+@pytest.mark.parametrize('norm', [None, 'ortho'])
+def test_overwrite(routine, dtype, shape, axis, type, norm, overwrite_x):
+    # Check input overwrite behavior
+    np.random.seed(1234)
+    if np.issubdtype(dtype, np.complexfloating):
+        x = np.random.randn(*shape) + 1j*np.random.randn(*shape)
+    else:
+        x = np.random.randn(*shape)
+    x = x.astype(dtype)
+    x2 = x.copy()
+    routine(x2, type, None, axis, norm, overwrite_x=overwrite_x)
+
+    sig = "{}({}{!r}, {!r}, axis={!r}, overwrite_x={!r})".format(
+        routine.__name__, x.dtype, x.shape, None, axis, overwrite_x)
+    if not overwrite_x:
+        assert_equal(x2, x, err_msg="spurious overwrite in %s" % sig)
+
+
+class Test_DCTN_IDCTN:
+    dec = 14
+    dct_type = [1, 2, 3, 4]
+    norms = [None, 'backward', 'ortho', 'forward']
+    rstate = np.random.RandomState(1234)
+    shape = (32, 16)
+    data = rstate.randn(*shape)
+
+    @pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
+                                                   (dstn, idstn)])
+    @pytest.mark.parametrize('axes', [None,
+                                      1, (1,), [1],
+                                      0, (0,), [0],
+                                      (0, 1), [0, 1],
+                                      (-2, -1), [-2, -1]])
+    @pytest.mark.parametrize('dct_type', dct_type)
+    @pytest.mark.parametrize('norm', ['ortho'])
+    def test_axes_round_trip(self, fforward, finverse, axes, dct_type, norm):
+        tmp = fforward(self.data, type=dct_type, axes=axes, norm=norm)
+        tmp = finverse(tmp, type=dct_type, axes=axes, norm=norm)
+        assert_array_almost_equal(self.data, tmp, decimal=12)
+
+    @pytest.mark.parametrize('funcn,func', [(dctn, dct), (dstn, dst)])
+    @pytest.mark.parametrize('dct_type', dct_type)
+    @pytest.mark.parametrize('norm', norms)
+    def test_dctn_vs_2d_reference(self, funcn, func, dct_type, norm):
+        y1 = funcn(self.data, type=dct_type, axes=None, norm=norm)
+        y2 = ref_2d(func, self.data, type=dct_type, norm=norm)
+        assert_array_almost_equal(y1, y2, decimal=11)
+
+    @pytest.mark.parametrize('funcn,func', [(idctn, idct), (idstn, idst)])
+    @pytest.mark.parametrize('dct_type', dct_type)
+    @pytest.mark.parametrize('norm', norms)
+    def test_idctn_vs_2d_reference(self, funcn, func, dct_type, norm):
+        fdata = dctn(self.data, type=dct_type, norm=norm)
+        y1 = funcn(fdata, type=dct_type, norm=norm)
+        y2 = ref_2d(func, fdata, type=dct_type, norm=norm)
+        assert_array_almost_equal(y1, y2, decimal=11)
+
+    @pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
+                                                   (dstn, idstn)])
+    def test_axes_and_shape(self, fforward, finverse):
+        with assert_raises(ValueError,
+                           match="when given, axes and shape arguments"
+                           " have to be of the same length"):
+            fforward(self.data, s=self.data.shape[0], axes=(0, 1))
+
+        with assert_raises(ValueError,
+                           match="when given, axes and shape arguments"
+                           " have to be of the same length"):
+            fforward(self.data, s=self.data.shape, axes=0)
+
+    @pytest.mark.parametrize('fforward', [dctn, dstn])
+    def test_shape(self, fforward):
+        tmp = fforward(self.data, s=(128, 128), axes=None)
+        assert_equal(tmp.shape, (128, 128))
+
+    @pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
+                                                   (dstn, idstn)])
+    @pytest.mark.parametrize('axes', [1, (1,), [1],
+                                      0, (0,), [0]])
+    def test_shape_is_none_with_axes(self, fforward, finverse, axes):
+        tmp = fforward(self.data, s=None, axes=axes, norm='ortho')
+        tmp = finverse(tmp, s=None, axes=axes, norm='ortho')
+        assert_array_almost_equal(self.data, tmp, decimal=self.dec)
+
+
+@pytest.mark.parametrize('func', [dct, dctn, idct, idctn,
+                                  dst, dstn, idst, idstn])
+def test_swapped_byte_order(func):
+    rng = np.random.RandomState(1234)
+    x = rng.rand(10)
+    swapped_dt = x.dtype.newbyteorder('S')
+    assert_allclose(func(x.astype(swapped_dt)), func(x))

venv/lib/python3.10/site-packages/scipy/fft/_realtransforms.py

@@ -0,0 +1,693 @@
+from ._basic import _dispatch
+from scipy._lib.uarray import Dispatchable
+import numpy as np
+
+__all__ = ['dct', 'idct', 'dst', 'idst', 'dctn', 'idctn', 'dstn', 'idstn']
+
+
+@_dispatch
+def dctn(x, type=2, s=None, axes=None, norm=None, overwrite_x=False,
+         workers=None, *, orthogonalize=None):
+    """
+    Return multidimensional Discrete Cosine Transform along the specified axes.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DCT (see Notes). Default type is 2.
+    s : int or array_like of ints or None, optional
+        The shape of the result. If both `s` and `axes` (see below) are None,
+        `s` is ``x.shape``; if `s` is None but `axes` is not None, then `s` is
+        ``numpy.take(x.shape, axes, axis=0)``.
+        If ``s[i] > x.shape[i]``, the ith dimension of the input is padded with zeros.
+        If ``s[i] < x.shape[i]``, the ith dimension of the input is truncated to length
+        ``s[i]``.
+        If any element of `s` is -1, the size of the corresponding dimension of
+        `x` is used.
+    axes : int or array_like of ints or None, optional
+        Axes over which the DCT is computed. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized DCT variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    y : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    idctn : Inverse multidimensional DCT
+
+    Notes
+    -----
+    For full details of the DCT types and normalization modes, as well as
+    references, see `dct`.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> from scipy.fft import dctn, idctn
+    >>> rng = np.random.default_rng()
+    >>> y = rng.standard_normal((16, 16))
+    >>> np.allclose(y, idctn(dctn(y)))
+    True
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def idctn(x, type=2, s=None, axes=None, norm=None, overwrite_x=False,
+          workers=None, orthogonalize=None):
+    """
+    Return multidimensional Inverse Discrete Cosine Transform along the specified axes.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DCT (see Notes). Default type is 2.
+    s : int or array_like of ints or None, optional
+        The shape of the result.  If both `s` and `axes` (see below) are
+        None, `s` is ``x.shape``; if `s` is None but `axes` is
+        not None, then `s` is ``numpy.take(x.shape, axes, axis=0)``.
+        If ``s[i] > x.shape[i]``, the ith dimension of the input is padded with zeros.
+        If ``s[i] < x.shape[i]``, the ith dimension of the input is truncated to length
+        ``s[i]``.
+        If any element of `s` is -1, the size of the corresponding dimension of
+        `x` is used.
+    axes : int or array_like of ints or None, optional
+        Axes over which the IDCT is computed. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized IDCT variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    y : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    dctn : multidimensional DCT
+
+    Notes
+    -----
+    For full details of the IDCT types and normalization modes, as well as
+    references, see `idct`.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> from scipy.fft import dctn, idctn
+    >>> rng = np.random.default_rng()
+    >>> y = rng.standard_normal((16, 16))
+    >>> np.allclose(y, idctn(dctn(y)))
+    True
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def dstn(x, type=2, s=None, axes=None, norm=None, overwrite_x=False,
+         workers=None, orthogonalize=None):
+    """
+    Return multidimensional Discrete Sine Transform along the specified axes.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DST (see Notes). Default type is 2.
+    s : int or array_like of ints or None, optional
+        The shape of the result.  If both `s` and `axes` (see below) are None,
+        `s` is ``x.shape``; if `s` is None but `axes` is not None, then `s` is
+        ``numpy.take(x.shape, axes, axis=0)``.
+        If ``s[i] > x.shape[i]``, the ith dimension of the input is padded with zeros.
+        If ``s[i] < x.shape[i]``, the ith dimension of the input is truncated to length
+        ``s[i]``.
+        If any element of `shape` is -1, the size of the corresponding dimension
+        of `x` is used.
+    axes : int or array_like of ints or None, optional
+        Axes over which the DST is computed. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized DST variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    y : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    idstn : Inverse multidimensional DST
+
+    Notes
+    -----
+    For full details of the DST types and normalization modes, as well as
+    references, see `dst`.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> from scipy.fft import dstn, idstn
+    >>> rng = np.random.default_rng()
+    >>> y = rng.standard_normal((16, 16))
+    >>> np.allclose(y, idstn(dstn(y)))
+    True
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def idstn(x, type=2, s=None, axes=None, norm=None, overwrite_x=False,
+          workers=None, orthogonalize=None):
+    """
+    Return multidimensional Inverse Discrete Sine Transform along the specified axes.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DST (see Notes). Default type is 2.
+    s : int or array_like of ints or None, optional
+        The shape of the result.  If both `s` and `axes` (see below) are None,
+        `s` is ``x.shape``; if `s` is None but `axes` is not None, then `s` is
+        ``numpy.take(x.shape, axes, axis=0)``.
+        If ``s[i] > x.shape[i]``, the ith dimension of the input is padded with zeros.
+        If ``s[i] < x.shape[i]``, the ith dimension of the input is truncated to length
+        ``s[i]``.
+        If any element of `s` is -1, the size of the corresponding dimension of
+        `x` is used.
+    axes : int or array_like of ints or None, optional
+        Axes over which the IDST is computed. If not given, the last ``len(s)``
+        axes are used, or all axes if `s` is also not specified.
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized IDST variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    y : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    dstn : multidimensional DST
+
+    Notes
+    -----
+    For full details of the IDST types and normalization modes, as well as
+    references, see `idst`.
+
+    Examples
+    --------
+    >>> import numpy as np
+    >>> from scipy.fft import dstn, idstn
+    >>> rng = np.random.default_rng()
+    >>> y = rng.standard_normal((16, 16))
+    >>> np.allclose(y, idstn(dstn(y)))
+    True
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def dct(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False, workers=None,
+        orthogonalize=None):
+    r"""Return the Discrete Cosine Transform of arbitrary type sequence x.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DCT (see Notes). Default type is 2.
+    n : int, optional
+        Length of the transform.  If ``n < x.shape[axis]``, `x` is
+        truncated.  If ``n > x.shape[axis]``, `x` is zero-padded. The
+        default results in ``n = x.shape[axis]``.
+    axis : int, optional
+        Axis along which the dct is computed; the default is over the
+        last axis (i.e., ``axis=-1``).
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized DCT variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    y : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    idct : Inverse DCT
+
+    Notes
+    -----
+    For a single dimension array ``x``, ``dct(x, norm='ortho')`` is equal to
+    MATLAB ``dct(x)``.
+
+    .. warning:: For ``type in {1, 2, 3}``, ``norm="ortho"`` breaks the direct
+                 correspondence with the direct Fourier transform. To recover
+                 it you must specify ``orthogonalize=False``.
+
+    For ``norm="ortho"`` both the `dct` and `idct` are scaled by the same
+    overall factor in both directions. By default, the transform is also
+    orthogonalized which for types 1, 2 and 3 means the transform definition is
+    modified to give orthogonality of the DCT matrix (see below).
+
+    For ``norm="backward"``, there is no scaling on `dct` and the `idct` is
+    scaled by ``1/N`` where ``N`` is the "logical" size of the DCT. For
+    ``norm="forward"`` the ``1/N`` normalization is applied to the forward
+    `dct` instead and the `idct` is unnormalized.
+
+    There are, theoretically, 8 types of the DCT, only the first 4 types are
+    implemented in SciPy.'The' DCT generally refers to DCT type 2, and 'the'
+    Inverse DCT generally refers to DCT type 3.
+
+    **Type I**
+
+    There are several definitions of the DCT-I; we use the following
+    (for ``norm="backward"``)
+
+    .. math::
+
+       y_k = x_0 + (-1)^k x_{N-1} + 2 \sum_{n=1}^{N-2} x_n \cos\left(
+       \frac{\pi k n}{N-1} \right)
+
+    If ``orthogonalize=True``, ``x[0]`` and ``x[N-1]`` are multiplied by a
+    scaling factor of :math:`\sqrt{2}`, and ``y[0]`` and ``y[N-1]`` are divided
+    by :math:`\sqrt{2}`. When combined with ``norm="ortho"``, this makes the
+    corresponding matrix of coefficients orthonormal (``O @ O.T = np.eye(N)``).
+
+    .. note::
+       The DCT-I is only supported for input size > 1.
+
+    **Type II**
+
+    There are several definitions of the DCT-II; we use the following
+    (for ``norm="backward"``)
+
+    .. math::
+
+       y_k = 2 \sum_{n=0}^{N-1} x_n \cos\left(\frac{\pi k(2n+1)}{2N} \right)
+
+    If ``orthogonalize=True``, ``y[0]`` is divided by :math:`\sqrt{2}` which,
+    when combined with ``norm="ortho"``, makes the corresponding matrix of
+    coefficients orthonormal (``O @ O.T = np.eye(N)``).
+
+    **Type III**
+
+    There are several definitions, we use the following (for
+    ``norm="backward"``)
+
+    .. math::
+
+       y_k = x_0 + 2 \sum_{n=1}^{N-1} x_n \cos\left(\frac{\pi(2k+1)n}{2N}\right)
+
+    If ``orthogonalize=True``, ``x[0]`` terms are multiplied by
+    :math:`\sqrt{2}` which, when combined with ``norm="ortho"``, makes the
+    corresponding matrix of coefficients orthonormal (``O @ O.T = np.eye(N)``).
+
+    The (unnormalized) DCT-III is the inverse of the (unnormalized) DCT-II, up
+    to a factor `2N`. The orthonormalized DCT-III is exactly the inverse of
+    the orthonormalized DCT-II.
+
+    **Type IV**
+
+    There are several definitions of the DCT-IV; we use the following
+    (for ``norm="backward"``)
+
+    .. math::
+
+       y_k = 2 \sum_{n=0}^{N-1} x_n \cos\left(\frac{\pi(2k+1)(2n+1)}{4N} \right)
+
+    ``orthogonalize`` has no effect here, as the DCT-IV matrix is already
+    orthogonal up to a scale factor of ``2N``.
+
+    References
+    ----------
+    .. [1] 'A Fast Cosine Transform in One and Two Dimensions', by J.
+           Makhoul, `IEEE Transactions on acoustics, speech and signal
+           processing` vol. 28(1), pp. 27-34,
+           :doi:`10.1109/TASSP.1980.1163351` (1980).
+    .. [2] Wikipedia, "Discrete cosine transform",
+           https://en.wikipedia.org/wiki/Discrete_cosine_transform
+
+    Examples
+    --------
+    The Type 1 DCT is equivalent to the FFT (though faster) for real,
+    even-symmetrical inputs. The output is also real and even-symmetrical.
+    Half of the FFT input is used to generate half of the FFT output:
+
+    >>> from scipy.fft import fft, dct
+    >>> import numpy as np
+    >>> fft(np.array([4., 3., 5., 10., 5., 3.])).real
+    array([ 30.,  -8.,   6.,  -2.,   6.,  -8.])
+    >>> dct(np.array([4., 3., 5., 10.]), 1)
+    array([ 30.,  -8.,   6.,  -2.])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def idct(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False,
+         workers=None, orthogonalize=None):
+    """
+    Return the Inverse Discrete Cosine Transform of an arbitrary type sequence.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DCT (see Notes). Default type is 2.
+    n : int, optional
+        Length of the transform.  If ``n < x.shape[axis]``, `x` is
+        truncated.  If ``n > x.shape[axis]``, `x` is zero-padded. The
+        default results in ``n = x.shape[axis]``.
+    axis : int, optional
+        Axis along which the idct is computed; the default is over the
+        last axis (i.e., ``axis=-1``).
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized IDCT variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    idct : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    dct : Forward DCT
+
+    Notes
+    -----
+    For a single dimension array `x`, ``idct(x, norm='ortho')`` is equal to
+    MATLAB ``idct(x)``.
+
+    .. warning:: For ``type in {1, 2, 3}``, ``norm="ortho"`` breaks the direct
+                 correspondence with the inverse direct Fourier transform. To
+                 recover it you must specify ``orthogonalize=False``.
+
+    For ``norm="ortho"`` both the `dct` and `idct` are scaled by the same
+    overall factor in both directions. By default, the transform is also
+    orthogonalized which for types 1, 2 and 3 means the transform definition is
+    modified to give orthogonality of the IDCT matrix (see `dct` for the full
+    definitions).
+
+    'The' IDCT is the IDCT-II, which is the same as the normalized DCT-III.
+
+    The IDCT is equivalent to a normal DCT except for the normalization and
+    type. DCT type 1 and 4 are their own inverse and DCTs 2 and 3 are each
+    other's inverses.
+
+    Examples
+    --------
+    The Type 1 DCT is equivalent to the DFT for real, even-symmetrical
+    inputs. The output is also real and even-symmetrical. Half of the IFFT
+    input is used to generate half of the IFFT output:
+
+    >>> from scipy.fft import ifft, idct
+    >>> import numpy as np
+    >>> ifft(np.array([ 30.,  -8.,   6.,  -2.,   6.,  -8.])).real
+    array([  4.,   3.,   5.,  10.,   5.,   3.])
+    >>> idct(np.array([ 30.,  -8.,   6.,  -2.]), 1)
+    array([  4.,   3.,   5.,  10.])
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def dst(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False, workers=None,
+        orthogonalize=None):
+    r"""
+    Return the Discrete Sine Transform of arbitrary type sequence x.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DST (see Notes). Default type is 2.
+    n : int, optional
+        Length of the transform. If ``n < x.shape[axis]``, `x` is
+        truncated.  If ``n > x.shape[axis]``, `x` is zero-padded. The
+        default results in ``n = x.shape[axis]``.
+    axis : int, optional
+        Axis along which the dst is computed; the default is over the
+        last axis (i.e., ``axis=-1``).
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized DST variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    dst : ndarray of reals
+        The transformed input array.
+
+    See Also
+    --------
+    idst : Inverse DST
+
+    Notes
+    -----
+    .. warning:: For ``type in {2, 3}``, ``norm="ortho"`` breaks the direct
+                 correspondence with the direct Fourier transform. To recover
+                 it you must specify ``orthogonalize=False``.
+
+    For ``norm="ortho"`` both the `dst` and `idst` are scaled by the same
+    overall factor in both directions. By default, the transform is also
+    orthogonalized which for types 2 and 3 means the transform definition is
+    modified to give orthogonality of the DST matrix (see below).
+
+    For ``norm="backward"``, there is no scaling on the `dst` and the `idst` is
+    scaled by ``1/N`` where ``N`` is the "logical" size of the DST.
+
+    There are, theoretically, 8 types of the DST for different combinations of
+    even/odd boundary conditions and boundary off sets [1]_, only the first
+    4 types are implemented in SciPy.
+
+    **Type I**
+
+    There are several definitions of the DST-I; we use the following for
+    ``norm="backward"``. DST-I assumes the input is odd around :math:`n=-1` and
+    :math:`n=N`.
+
+    .. math::
+
+        y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(k+1)(n+1)}{N+1}\right)
+
+    Note that the DST-I is only supported for input size > 1.
+    The (unnormalized) DST-I is its own inverse, up to a factor :math:`2(N+1)`.
+    The orthonormalized DST-I is exactly its own inverse.
+
+    ``orthogonalize`` has no effect here, as the DST-I matrix is already
+    orthogonal up to a scale factor of ``2N``.
+
+    **Type II**
+
+    There are several definitions of the DST-II; we use the following for
+    ``norm="backward"``. DST-II assumes the input is odd around :math:`n=-1/2` and
+    :math:`n=N-1/2`; the output is odd around :math:`k=-1` and even around :math:`k=N-1`
+
+    .. math::
+
+        y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(k+1)(2n+1)}{2N}\right)
+
+    If ``orthogonalize=True``, ``y[-1]`` is divided :math:`\sqrt{2}` which, when
+    combined with ``norm="ortho"``, makes the corresponding matrix of
+    coefficients orthonormal (``O @ O.T = np.eye(N)``).
+
+    **Type III**
+
+    There are several definitions of the DST-III, we use the following (for
+    ``norm="backward"``). DST-III assumes the input is odd around :math:`n=-1` and
+    even around :math:`n=N-1`
+
+    .. math::
+
+        y_k = (-1)^k x_{N-1} + 2 \sum_{n=0}^{N-2} x_n \sin\left(
+        \frac{\pi(2k+1)(n+1)}{2N}\right)
+
+    If ``orthogonalize=True``, ``x[-1]`` is multiplied by :math:`\sqrt{2}`
+    which, when combined with ``norm="ortho"``, makes the corresponding matrix
+    of coefficients orthonormal (``O @ O.T = np.eye(N)``).
+
+    The (unnormalized) DST-III is the inverse of the (unnormalized) DST-II, up
+    to a factor :math:`2N`. The orthonormalized DST-III is exactly the inverse of the
+    orthonormalized DST-II.
+
+    **Type IV**
+
+    There are several definitions of the DST-IV, we use the following (for
+    ``norm="backward"``). DST-IV assumes the input is odd around :math:`n=-0.5` and
+    even around :math:`n=N-0.5`
+
+    .. math::
+
+        y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(2k+1)(2n+1)}{4N}\right)
+
+    ``orthogonalize`` has no effect here, as the DST-IV matrix is already
+    orthogonal up to a scale factor of ``2N``.
+
+    The (unnormalized) DST-IV is its own inverse, up to a factor :math:`2N`. The
+    orthonormalized DST-IV is exactly its own inverse.
+
+    References
+    ----------
+    .. [1] Wikipedia, "Discrete sine transform",
+           https://en.wikipedia.org/wiki/Discrete_sine_transform
+
+    """
+    return (Dispatchable(x, np.ndarray),)
+
+
+@_dispatch
+def idst(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False,
+         workers=None, orthogonalize=None):
+    """
+    Return the Inverse Discrete Sine Transform of an arbitrary type sequence.
+
+    Parameters
+    ----------
+    x : array_like
+        The input array.
+    type : {1, 2, 3, 4}, optional
+        Type of the DST (see Notes). Default type is 2.
+    n : int, optional
+        Length of the transform. If ``n < x.shape[axis]``, `x` is
+        truncated.  If ``n > x.shape[axis]``, `x` is zero-padded. The
+        default results in ``n = x.shape[axis]``.
+    axis : int, optional
+        Axis along which the idst is computed; the default is over the
+        last axis (i.e., ``axis=-1``).
+    norm : {"backward", "ortho", "forward"}, optional
+        Normalization mode (see Notes). Default is "backward".
+    overwrite_x : bool, optional
+        If True, the contents of `x` can be destroyed; the default is False.
+    workers : int, optional
+        Maximum number of workers to use for parallel computation. If negative,
+        the value wraps around from ``os.cpu_count()``.
+        See :func:`~scipy.fft.fft` for more details.
+    orthogonalize : bool, optional
+        Whether to use the orthogonalized IDST variant (see Notes).
+        Defaults to ``True`` when ``norm="ortho"`` and ``False`` otherwise.
+
+        .. versionadded:: 1.8.0
+
+    Returns
+    -------
+    idst : ndarray of real
+        The transformed input array.
+
+    See Also
+    --------
+    dst : Forward DST
+
+    Notes
+    -----
+    .. warning:: For ``type in {2, 3}``, ``norm="ortho"`` breaks the direct
+                 correspondence with the inverse direct Fourier transform.
+
+    For ``norm="ortho"`` both the `dst` and `idst` are scaled by the same
+    overall factor in both directions. By default, the transform is also
+    orthogonalized which for types 2 and 3 means the transform definition is
+    modified to give orthogonality of the DST matrix (see `dst` for the full
+    definitions).
+
+    'The' IDST is the IDST-II, which is the same as the normalized DST-III.
+
+    The IDST is equivalent to a normal DST except for the normalization and
+    type. DST type 1 and 4 are their own inverse and DSTs 2 and 3 are each
+    other's inverses.
+
+    """
+    return (Dispatchable(x, np.ndarray),)

venv/lib/python3.10/site-packages/scipy/fft/_realtransforms_backend.py

@@ -0,0 +1,63 @@
+from scipy._lib._array_api import array_namespace
+import numpy as np
+from . import _pocketfft
+
+__all__ = ['dct', 'idct', 'dst', 'idst', 'dctn', 'idctn', 'dstn', 'idstn']
+
+
+def _execute(pocketfft_func, x, type, s, axes, norm, 
+             overwrite_x, workers, orthogonalize):
+    xp = array_namespace(x)
+    x = np.asarray(x)
+    y = pocketfft_func(x, type, s, axes, norm,
+                       overwrite_x=overwrite_x, workers=workers,
+                       orthogonalize=orthogonalize)
+    return xp.asarray(y)
+
+
+def dctn(x, type=2, s=None, axes=None, norm=None,
+         overwrite_x=False, workers=None, *, orthogonalize=None):
+    return _execute(_pocketfft.dctn, x, type, s, axes, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def idctn(x, type=2, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, *, orthogonalize=None):
+    return _execute(_pocketfft.idctn, x, type, s, axes, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def dstn(x, type=2, s=None, axes=None, norm=None,
+         overwrite_x=False, workers=None, orthogonalize=None):
+    return _execute(_pocketfft.dstn, x, type, s, axes, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def idstn(x, type=2, s=None, axes=None, norm=None,
+          overwrite_x=False, workers=None, *, orthogonalize=None):
+    return _execute(_pocketfft.idstn, x, type, s, axes, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def dct(x, type=2, n=None, axis=-1, norm=None,
+        overwrite_x=False, workers=None, orthogonalize=None):
+    return _execute(_pocketfft.dct, x, type, n, axis, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def idct(x, type=2, n=None, axis=-1, norm=None,
+         overwrite_x=False, workers=None, orthogonalize=None):
+    return _execute(_pocketfft.idct, x, type, n, axis, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def dst(x, type=2, n=None, axis=-1, norm=None,
+        overwrite_x=False, workers=None, orthogonalize=None):
+    return _execute(_pocketfft.dst, x, type, n, axis, norm, 
+                    overwrite_x, workers, orthogonalize)
+
+
+def idst(x, type=2, n=None, axis=-1, norm=None,
+         overwrite_x=False, workers=None, orthogonalize=None):
+    return _execute(_pocketfft.idst, x, type, n, axis, norm, 
+                    overwrite_x, workers, orthogonalize)

venv/lib/python3.10/site-packages/scipy/fft/tests/mock_backend.py

@@ -0,0 +1,92 @@
+import numpy as np
+import scipy.fft
+
+class _MockFunction:
+    def __init__(self, return_value = None):
+        self.number_calls = 0
+        self.return_value = return_value
+        self.last_args = ([], {})
+
+    def __call__(self, *args, **kwargs):
+        self.number_calls += 1
+        self.last_args = (args, kwargs)
+        return self.return_value
+
+
+fft = _MockFunction(np.random.random(10))
+fft2 = _MockFunction(np.random.random(10))
+fftn = _MockFunction(np.random.random(10))
+
+ifft = _MockFunction(np.random.random(10))
+ifft2 = _MockFunction(np.random.random(10))
+ifftn = _MockFunction(np.random.random(10))
+
+rfft = _MockFunction(np.random.random(10))
+rfft2 = _MockFunction(np.random.random(10))
+rfftn = _MockFunction(np.random.random(10))
+
+irfft = _MockFunction(np.random.random(10))
+irfft2 = _MockFunction(np.random.random(10))
+irfftn = _MockFunction(np.random.random(10))
+
+hfft = _MockFunction(np.random.random(10))
+hfft2 = _MockFunction(np.random.random(10))
+hfftn = _MockFunction(np.random.random(10))
+
+ihfft = _MockFunction(np.random.random(10))
+ihfft2 = _MockFunction(np.random.random(10))
+ihfftn = _MockFunction(np.random.random(10))
+
+dct = _MockFunction(np.random.random(10))
+idct = _MockFunction(np.random.random(10))
+dctn = _MockFunction(np.random.random(10))
+idctn = _MockFunction(np.random.random(10))
+
+dst = _MockFunction(np.random.random(10))
+idst = _MockFunction(np.random.random(10))
+dstn = _MockFunction(np.random.random(10))
+idstn = _MockFunction(np.random.random(10))
+
+fht = _MockFunction(np.random.random(10))
+ifht = _MockFunction(np.random.random(10))
+
+
+__ua_domain__ = "numpy.scipy.fft"
+
+
+_implements = {
+    scipy.fft.fft: fft,
+    scipy.fft.fft2: fft2,
+    scipy.fft.fftn: fftn,
+    scipy.fft.ifft: ifft,
+    scipy.fft.ifft2: ifft2,
+    scipy.fft.ifftn: ifftn,
+    scipy.fft.rfft: rfft,
+    scipy.fft.rfft2: rfft2,
+    scipy.fft.rfftn: rfftn,
+    scipy.fft.irfft: irfft,
+    scipy.fft.irfft2: irfft2,
+    scipy.fft.irfftn: irfftn,
+    scipy.fft.hfft: hfft,
+    scipy.fft.hfft2: hfft2,
+    scipy.fft.hfftn: hfftn,
+    scipy.fft.ihfft: ihfft,
+    scipy.fft.ihfft2: ihfft2,
+    scipy.fft.ihfftn: ihfftn,
+    scipy.fft.dct: dct,
+    scipy.fft.idct: idct,
+    scipy.fft.dctn: dctn,
+    scipy.fft.idctn: idctn,
+    scipy.fft.dst: dst,
+    scipy.fft.idst: idst,
+    scipy.fft.dstn: dstn,
+    scipy.fft.idstn: idstn,
+    scipy.fft.fht: fht,
+    scipy.fft.ifht: ifht
+}
+
+
+def __ua_function__(method, args, kwargs):
+    fn = _implements.get(method)
+    return (fn(*args, **kwargs) if fn is not None
+            else NotImplemented)