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55,662
distrax._src.distributions.epsilon_greedy
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'EpsilonGreedy': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return EpsilonGreedy( preferences=self.preferences[index], epsilon=self.epsilon, dtype=self.dtype)
(self, index) -> distrax._src.distributions.epsilon_greedy.EpsilonGreedy
55,663
distrax._src.distributions.epsilon_greedy
__init__
Initializes an EpsilonGreedy distribution. Args: preferences: Unnormalized preferences. epsilon: Mixing parameter ε. dtype: The type of event samples.
def __init__(self, preferences: Array, epsilon: float, dtype: Union[jnp.dtype, type[Any]] = int): """Initializes an EpsilonGreedy distribution. Args: preferences: Unnormalized preferences. epsilon: Mixing parameter ε. dtype: The type of event samples. """ self._preferences = jnp.asarray(preferences) self._epsilon = epsilon greedy_probs = _argmax_with_random_tie_breaking(self._preferences) probs = _mix_probs_with_uniform(greedy_probs, epsilon) super().__init__(probs=probs, dtype=dtype)
(self, preferences: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], epsilon: float, dtype: Union[numpy.dtype, type[Any]] = <class 'int'>)
55,686
distrax._src.distributions.gamma
Gamma
Gamma distribution with parameters `concentration` and `rate`.
class Gamma(distribution.Distribution): """Gamma distribution with parameters `concentration` and `rate`.""" equiv_tfp_cls = tfd.Gamma def __init__(self, concentration: Numeric, rate: Numeric): """Initializes a Gamma distribution. Args: concentration: Concentration parameter of the distribution. rate: Inverse scale params of the distribution. """ super().__init__() self._concentration = conversion.as_float_array(concentration) self._rate = conversion.as_float_array(rate) self._batch_shape = jax.lax.broadcast_shapes( self._concentration.shape, self._rate.shape) @property def event_shape(self) -> Tuple[int, ...]: """Shape of event of distribution samples.""" return () @property def batch_shape(self) -> Tuple[int, ...]: """Shape of batch of distribution samples.""" return self._batch_shape @property def concentration(self) -> Array: """Concentration of the distribution.""" return jnp.broadcast_to(self._concentration, self.batch_shape) @property def rate(self) -> Array: """Inverse scale of the distribution.""" return jnp.broadcast_to(self._rate, self.batch_shape) def _sample_from_std_gamma(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._concentration, self._rate) return jax.random.gamma( key, a=self._concentration, shape=out_shape, dtype=dtype ) def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_gamma(key, n) return rnd / self._rate def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" return ( self._concentration * jnp.log(self._rate) + (self._concentration - 1) * jnp.log(value) - self._rate * value - jax.lax.lgamma(self._concentration) ) def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" log_rate = jnp.log(self._rate) return ( self._concentration - log_rate + jax.lax.lgamma(self._concentration) + (1.0 - self._concentration) * jax.lax.digamma(self._concentration) ) def cdf(self, value: EventT) -> Array: """See `Distribution.cdf`.""" return jax.lax.igamma(self._concentration, self._rate * value) def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" return jnp.log(self.cdf(value)) def mean(self) -> Array: """Calculates the mean.""" return self._concentration / self._rate def stddev(self) -> Array: """Calculates the standard deviation.""" return jnp.sqrt(self._concentration) / self._rate def variance(self) -> Array: """Calculates the variance.""" return self._concentration / jnp.square(self._rate) def mode(self) -> Array: """Calculates the mode.""" mode = (self._concentration - 1.0) / self._rate return jnp.where(self._concentration >= 1.0, mode, jnp.nan) def __getitem__(self, index) -> 'Gamma': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Gamma( concentration=self.concentration[index], rate=self.rate[index])
(concentration: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], rate: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,687
distrax._src.distributions.gamma
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Gamma': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Gamma( concentration=self.concentration[index], rate=self.rate[index])
(self, index) -> distrax._src.distributions.gamma.Gamma
55,688
distrax._src.distributions.gamma
__init__
Initializes a Gamma distribution. Args: concentration: Concentration parameter of the distribution. rate: Inverse scale params of the distribution.
def __init__(self, concentration: Numeric, rate: Numeric): """Initializes a Gamma distribution. Args: concentration: Concentration parameter of the distribution. rate: Inverse scale params of the distribution. """ super().__init__() self._concentration = conversion.as_float_array(concentration) self._rate = conversion.as_float_array(rate) self._batch_shape = jax.lax.broadcast_shapes( self._concentration.shape, self._rate.shape)
(self, concentration: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], rate: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,691
distrax._src.distributions.gamma
_sample_from_std_gamma
null
def _sample_from_std_gamma(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._concentration, self._rate) return jax.random.gamma( key, a=self._concentration, shape=out_shape, dtype=dtype )
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,692
distrax._src.distributions.gamma
_sample_n
See `Distribution._sample_n`.
def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_gamma(key, n) return rnd / self._rate
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,694
distrax._src.distributions.gamma
cdf
See `Distribution.cdf`.
def cdf(self, value: EventT) -> Array: """See `Distribution.cdf`.""" return jax.lax.igamma(self._concentration, self._rate * value)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,696
distrax._src.distributions.gamma
entropy
Calculates the Shannon entropy (in nats).
def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" log_rate = jnp.log(self._rate) return ( self._concentration - log_rate + jax.lax.lgamma(self._concentration) + (1.0 - self._concentration) * jax.lax.digamma(self._concentration) )
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,699
distrax._src.distributions.gamma
log_prob
See `Distribution.log_prob`.
def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" return ( self._concentration * jnp.log(self._rate) + (self._concentration - 1) * jnp.log(value) - self._rate * value - jax.lax.lgamma(self._concentration) )
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,701
distrax._src.distributions.gamma
mean
Calculates the mean.
def mean(self) -> Array: """Calculates the mean.""" return self._concentration / self._rate
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,703
distrax._src.distributions.gamma
mode
Calculates the mode.
def mode(self) -> Array: """Calculates the mode.""" mode = (self._concentration - 1.0) / self._rate return jnp.where(self._concentration >= 1.0, mode, jnp.nan)
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,707
distrax._src.distributions.gamma
stddev
Calculates the standard deviation.
def stddev(self) -> Array: """Calculates the standard deviation.""" return jnp.sqrt(self._concentration) / self._rate
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,710
distrax._src.distributions.gamma
variance
Calculates the variance.
def variance(self) -> Array: """Calculates the variance.""" return self._concentration / jnp.square(self._rate)
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,711
distrax._src.distributions.greedy
Greedy
A Categorical distribution that is greedy with respect to some preferences. Given a set of unnormalized preferences, the probability mass is distributed equally among all indices `i` such that `preferences[i] = max(preferences)`, all other indices will be assigned a probability of zero.
class Greedy(categorical.Categorical): """A Categorical distribution that is greedy with respect to some preferences. Given a set of unnormalized preferences, the probability mass is distributed equally among all indices `i` such that `preferences[i] = max(preferences)`, all other indices will be assigned a probability of zero. """ def __init__( self, preferences: Array, dtype: Union[jnp.dtype, type[Any]] = int ): """Initializes a Greedy distribution. Args: preferences: Unnormalized preferences. dtype: The type of event samples. """ self._preferences = jnp.asarray(preferences) probs = _argmax_with_random_tie_breaking(self._preferences) super().__init__(probs=probs, dtype=dtype) @property def preferences(self) -> Array: """Unnormalized preferences.""" return self._preferences def __getitem__(self, index) -> 'Greedy': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Greedy( preferences=self.preferences[index], dtype=self.dtype)
(preferences: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], dtype: Union[numpy.dtype, type[Any]] = <class 'int'>)
55,712
distrax._src.distributions.greedy
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Greedy': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Greedy( preferences=self.preferences[index], dtype=self.dtype)
(self, index) -> distrax._src.distributions.greedy.Greedy
55,713
distrax._src.distributions.greedy
__init__
Initializes a Greedy distribution. Args: preferences: Unnormalized preferences. dtype: The type of event samples.
def __init__( self, preferences: Array, dtype: Union[jnp.dtype, type[Any]] = int ): """Initializes a Greedy distribution. Args: preferences: Unnormalized preferences. dtype: The type of event samples. """ self._preferences = jnp.asarray(preferences) probs = _argmax_with_random_tie_breaking(self._preferences) super().__init__(probs=probs, dtype=dtype)
(self, preferences: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], dtype: Union[numpy.dtype, type[Any]] = <class 'int'>)
55,736
distrax._src.distributions.gumbel
Gumbel
Gumbel distribution with location `loc` and `scale` parameters.
class Gumbel(distribution.Distribution): """Gumbel distribution with location `loc` and `scale` parameters.""" equiv_tfp_cls = tfd.Gumbel def __init__(self, loc: Numeric, scale: Numeric): """Initializes a Gumbel distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution. """ super().__init__() self._loc = conversion.as_float_array(loc) self._scale = conversion.as_float_array(scale) self._batch_shape = jax.lax.broadcast_shapes( self._loc.shape, self._scale.shape) @property def event_shape(self) -> Tuple[int, ...]: """Shape of event of distribution samples.""" return () @property def batch_shape(self) -> Tuple[int, ...]: """Shape of batch of distribution samples.""" return self._batch_shape @property def loc(self) -> Array: """Mean of the distribution.""" return jnp.broadcast_to(self._loc, self.batch_shape) @property def scale(self) -> Array: """Scale of the distribution.""" return jnp.broadcast_to(self._scale, self.batch_shape) def _standardize(self, value: Array) -> Array: """Standardizes the input `value` in location and scale.""" return (value - self._loc) / self._scale def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" z = self._standardize(value) return -(z + jnp.exp(-z)) - jnp.log(self._scale) def _sample_from_std_gumbel(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._loc, self._scale) return jax.random.gumbel(key, shape=out_shape, dtype=dtype) def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_gumbel(key, n) return self._scale * rnd + self._loc def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" rnd = self._sample_from_std_gumbel(key, n) samples = self._scale * rnd + self._loc log_prob = -(rnd + jnp.exp(-rnd)) - jnp.log(self._scale) return samples, log_prob def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" return jnp.log(self._scale) + 1. + jnp.euler_gamma def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" z = self._standardize(value) return -jnp.exp(-z) def mean(self) -> Array: """Calculates the mean.""" return self._loc + self._scale * jnp.euler_gamma def stddev(self) -> Array: """Calculates the standard deviation.""" return self._scale * jnp.ones_like(self._loc) * jnp.pi / math.sqrt(6.) def variance(self) -> Array: """Calculates the variance.""" return jnp.square(self._scale * jnp.ones_like(self._loc) * jnp.pi) / 6. def mode(self) -> Array: """Calculates the mode.""" return self.loc def median(self) -> Array: """Calculates the median.""" return self._loc - self._scale * math.log(math.log(2.)) def __getitem__(self, index) -> 'Gumbel': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Gumbel(loc=self.loc[index], scale=self.scale[index])
(loc: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], scale: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,737
distrax._src.distributions.gumbel
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Gumbel': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Gumbel(loc=self.loc[index], scale=self.scale[index])
(self, index) -> distrax._src.distributions.gumbel.Gumbel
55,738
distrax._src.distributions.gumbel
__init__
Initializes a Gumbel distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution.
def __init__(self, loc: Numeric, scale: Numeric): """Initializes a Gumbel distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution. """ super().__init__() self._loc = conversion.as_float_array(loc) self._scale = conversion.as_float_array(scale) self._batch_shape = jax.lax.broadcast_shapes( self._loc.shape, self._scale.shape)
(self, loc: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], scale: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,741
distrax._src.distributions.gumbel
_sample_from_std_gumbel
null
def _sample_from_std_gumbel(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._loc, self._scale) return jax.random.gumbel(key, shape=out_shape, dtype=dtype)
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,742
distrax._src.distributions.gumbel
_sample_n
See `Distribution._sample_n`.
def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_gumbel(key, n) return self._scale * rnd + self._loc
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,743
distrax._src.distributions.gumbel
_sample_n_and_log_prob
See `Distribution._sample_n_and_log_prob`.
def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" rnd = self._sample_from_std_gumbel(key, n) samples = self._scale * rnd + self._loc log_prob = -(rnd + jnp.exp(-rnd)) - jnp.log(self._scale) return samples, log_prob
(self, key: jax.Array, n: int) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,744
distrax._src.distributions.gumbel
_standardize
Standardizes the input `value` in location and scale.
def _standardize(self, value: Array) -> Array: """Standardizes the input `value` in location and scale.""" return (value - self._loc) / self._scale
(self, value: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,747
distrax._src.distributions.gumbel
entropy
Calculates the Shannon entropy (in nats).
def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" return jnp.log(self._scale) + 1. + jnp.euler_gamma
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,749
distrax._src.distributions.gumbel
log_cdf
See `Distribution.log_cdf`.
def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" z = self._standardize(value) return -jnp.exp(-z)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,750
distrax._src.distributions.gumbel
log_prob
See `Distribution.log_prob`.
def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" z = self._standardize(value) return -(z + jnp.exp(-z)) - jnp.log(self._scale)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,752
distrax._src.distributions.gumbel
mean
Calculates the mean.
def mean(self) -> Array: """Calculates the mean.""" return self._loc + self._scale * jnp.euler_gamma
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,753
distrax._src.distributions.gumbel
median
Calculates the median.
def median(self) -> Array: """Calculates the median.""" return self._loc - self._scale * math.log(math.log(2.))
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,754
distrax._src.distributions.gumbel
mode
Calculates the mode.
def mode(self) -> Array: """Calculates the mode.""" return self.loc
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,758
distrax._src.distributions.gumbel
stddev
Calculates the standard deviation.
def stddev(self) -> Array: """Calculates the standard deviation.""" return self._scale * jnp.ones_like(self._loc) * jnp.pi / math.sqrt(6.)
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,761
distrax._src.distributions.gumbel
variance
Calculates the variance.
def variance(self) -> Array: """Calculates the variance.""" return jnp.square(self._scale * jnp.ones_like(self._loc) * jnp.pi) / 6.
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,762
distrax._src.bijectors.gumbel_cdf
GumbelCDF
A bijector that computes the Gumbel cumulative density function (CDF). The Gumbel CDF is given by `y = f(x) = exp(-exp(-x))` for a scalar input `x`. Its inverse is `x = -log(-log(y))`. The log-det Jacobian of the transformation is `log df/dx = -exp(-x) - x`.
class GumbelCDF(base.Bijector): """A bijector that computes the Gumbel cumulative density function (CDF). The Gumbel CDF is given by `y = f(x) = exp(-exp(-x))` for a scalar input `x`. Its inverse is `x = -log(-log(y))`. The log-det Jacobian of the transformation is `log df/dx = -exp(-x) - x`. """ def __init__(self): """Initializes a GumbelCDF bijector.""" super().__init__(event_ndims_in=0) def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" exp_neg_x = jnp.exp(-x) y = jnp.exp(-exp_neg_x) log_det = - x - exp_neg_x return y, log_det def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" log_y = jnp.log(y) x = -jnp.log(-log_y) return x, x - log_y def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" return type(other) is GumbelCDF # pylint: disable=unidiomatic-typecheck
()
55,763
distrax._src.bijectors.gumbel_cdf
__init__
Initializes a GumbelCDF bijector.
def __init__(self): """Initializes a GumbelCDF bijector.""" super().__init__(event_ndims_in=0)
(self)
55,768
distrax._src.bijectors.gumbel_cdf
forward_and_log_det
Computes y = f(x) and log|det J(f)(x)|.
def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" exp_neg_x = jnp.exp(-x) y = jnp.exp(-exp_neg_x) log_det = - x - exp_neg_x return y, log_det
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,771
distrax._src.bijectors.gumbel_cdf
inverse_and_log_det
Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.
def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" log_y = jnp.log(y) x = -jnp.log(-log_y) return x, x - log_y
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,773
distrax._src.bijectors.gumbel_cdf
same_as
Returns True if this bijector is guaranteed to be the same as `other`.
def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" return type(other) is GumbelCDF # pylint: disable=unidiomatic-typecheck
(self, other: distrax._src.bijectors.bijector.Bijector) -> bool
55,775
distrax._src.utils.hmm
HMM
Hidden Markov Model class.
class HMM(jittable.Jittable): """Hidden Markov Model class.""" def __init__(self, init_dist: categorical.CategoricalLike, trans_dist: categorical.CategoricalLike, obs_dist: distribution.DistributionLike): """Constructs an N-state Hidden Markov Model from component distributions. Args: init_dist: Integer-valued categorical distribution with parameters of shape (N,), representing the distribution over initial latent states. trans_dist: Integer-valued categorical distribution with parameters of shape (N, N), representing the transition probability matrix between latent states. obs_dist: Any observation distribution with batch shape (N,), representing `p(observation|latent state)`. """ self._init_dist = conversion.as_distribution(init_dist) self._trans_dist = conversion.as_distribution(trans_dist) self._obs_dist = conversion.as_distribution(obs_dist) self._n_states = self._init_dist.num_categories if not jnp.issubdtype(self._init_dist.dtype, jnp.integer): raise TypeError( f'init_dist must be categorical-like with integer dtype, but its ' f'dtype is {self._init_dist.dtype}.') if not jnp.issubdtype(self._trans_dist.dtype, jnp.integer): raise TypeError( f'trans_dist must be categorical-like with integer dtype, but its ' f'dtype is {self._trans_dist.dtype}.') if self._init_dist.batch_shape: raise ValueError( f'init_dist must be unbatched, but it has a batch shape of ' f'{self._init_dist.batch_shape}.') if self._obs_dist.batch_shape != (self._n_states,): raise ValueError( f'obs_dist should have batch shape of ({self._n_states},) equal to ' f'the number of latent states in the model, but its batch shape is ' f'{self._obs_dist.batch_shape}.') if self._trans_dist.batch_shape != (self._n_states,): raise ValueError( f'trans_dist should have batch shape of ({self._n_states},) equal to ' f'the number of latent states in the model, but its batch shape is ' f'{self._trans_dist.batch_shape}.') if self._trans_dist.num_categories != self._n_states: raise ValueError( f'trans_dist should have `num_categories` of {self._n_states} equal ' f'to the number of latent states in the model, but it has ' f'`num_categories` of {self._trans_dist.num_categories}.') @property def init_dist(self) -> categorical.CategoricalLike: return self._init_dist @property def trans_dist(self) -> categorical.CategoricalLike: return self._trans_dist @property def obs_dist(self) -> distribution.DistributionLike: return self._obs_dist def sample(self, *, seed: chex.PRNGKey, seq_len: int) -> Tuple[chex.Array, chex.Array]: """Sample from this HMM. Samples an observation of given length according to this Hidden Markov Model and gives the sequence of the hidden states as well as the observation. Args: seed: Random key of shape (2,) and dtype uint32. seq_len: The length of the observation sequence. Returns: Tuple of hidden state sequence, and observation sequence. """ rng_key, rng_init = jax.random.split(seed) initial_state = self._init_dist.sample(seed=rng_init) def draw_state(prev_state, key): state = self._trans_dist.sample(seed=key)[prev_state] return state, state rng_state, rng_obs = jax.random.split(rng_key) keys = jax.random.split(rng_state, seq_len - 1) _, states = jax.lax.scan(draw_state, initial_state, keys) states = jnp.append(initial_state, states) def draw_obs(state, key): return self._obs_dist.sample(seed=key)[state] keys = jax.random.split(rng_obs, seq_len) obs_seq = jax.vmap(draw_obs, in_axes=(0, 0))(states, keys) return states, obs_seq def forward(self, obs_seq: chex.Array, length: Optional[chex.Array] = None) -> Tuple[float, chex.Array]: """Calculates a belief state. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of `log(p(x_{1:T}|model))` and the array of forward joint probabilities `p(z_t,x_{1:t})` for each sample `x_t`. """ seq_len = len(obs_seq) if length is None: length = seq_len def scan_fn(carry, t): (alpha_prev, log_ll_prev) = carry alpha_n = jnp.where( t < length, (self._obs_dist.prob(obs_seq[t]) * (alpha_prev[:, None] * self._trans_dist.probs).sum(axis=0)), jnp.zeros_like(alpha_prev)) alpha_n, cn = _normalize(alpha_n) carry = (alpha_n, jnp.log(cn) + log_ll_prev) return carry, alpha_n # initial belief state alpha_0, c0 = _normalize( self._init_dist.probs * self._obs_dist.prob(obs_seq[0])) # setup scan loop init_state = (alpha_0, jnp.log(c0)) ts = jnp.arange(1, seq_len) carry, alpha_hist = jax.lax.scan(scan_fn, init_state, ts) # post-process alpha_hist = jnp.vstack([alpha_0.reshape(1, self._n_states), alpha_hist]) (_, log_ll) = carry return log_ll, alpha_hist def backward(self, obs_seq: chex.Array, length: Optional[chex.Array] = None) -> chex.Array: """Computes the backward probabilities. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Array of backward joint probabilities `p(x_{t+1:T}|z_t)`. """ seq_len = len(obs_seq) if length is None: length = seq_len beta_t = jnp.ones((self._n_states,)) def scan_fn(beta_prev, t): beta_t = jnp.where( t > length, jnp.zeros_like(beta_prev), _normalize((beta_prev * self._obs_dist.prob(obs_seq[t-1]) * self._trans_dist.probs).sum(axis=1))[0]) return beta_t, beta_t ts = jnp.arange(seq_len, 1, -1) _, beta_hist = jax.lax.scan(scan_fn, beta_t, ts) beta_hist = jnp.flip( jnp.vstack([beta_t.reshape(1, self._n_states), beta_hist]), axis=0) return beta_hist def forward_backward( self, obs_seq: chex.Array, length: Optional[chex.Array] = None, ) -> Tuple[chex.Array, chex.Array, chex.Array, float]: """HMM forward-backward algorithm. Computes, for each time step, the marginal conditional probability that the Hidden Markov Model was in each possible state given the observations that were made at each time step, i.e. P(z[i] | x[0], ..., x[num_steps - 1]) for all i from 0 to num_steps - 1. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of: * Forward joint probabilities `p(z_t,x_{1:t})`. * Backward joint probabilities `p(x_{t+1:T}|z_t)`. * Marginal conditional probability of the observations. * The log-likelihood log(p(x_{1:T}|model)). """ seq_len = len(obs_seq) if length is None: length = seq_len def gamma_t(t): return alpha[t] * beta[t] ll, alpha = self.forward(obs_seq, length) beta = self.backward(obs_seq, length) ts = jnp.arange(seq_len) gamma = jax.vmap(gamma_t)(ts) gamma = jax.vmap(lambda x: _normalize(x)[0])(gamma) return alpha, beta, gamma, ll def viterbi(self, obs_seq: chex.Array) -> chex.Array: """Viterbi algorithm. Computes the most probable sequence of hidden states given the observations. Args: obs_seq: Observation sequence. Returns: The most probable sequence of hidden states. """ trans_log_probs = jax.nn.log_softmax(self._trans_dist.logits) init_log_probs = jax.nn.log_softmax(self._init_dist.logits) first_log_prob = init_log_probs + self._obs_dist.log_prob(obs_seq[0]) if len(obs_seq) == 1: return jnp.expand_dims(jnp.argmax(first_log_prob), axis=0) def viterbi_forward(prev_logp, obs): obs_logp = self._obs_dist.log_prob(obs) logp = prev_logp[..., None] + trans_log_probs + obs_logp[..., None, :] max_logp_given_successor = jnp.max(logp, axis=-2) most_likely_given_successor = jnp.argmax(logp, axis=-2) return max_logp_given_successor, most_likely_given_successor final_log_prob, most_likely_sources = jax.lax.scan( viterbi_forward, first_log_prob, obs_seq[1:]) most_likely_initial_given_successor = jnp.argmax( trans_log_probs + first_log_prob, axis=-2) most_likely_sources = jnp.concatenate([ jnp.expand_dims(most_likely_initial_given_successor, axis=0), most_likely_sources], axis=0) def viterbi_backward(state, most_likely_sources): state = jax.nn.one_hot(state, self._n_states) most_likely = jnp.sum(most_likely_sources * state).astype(jnp.int64) return most_likely, most_likely final_state = jnp.argmax(final_log_prob) _, most_likely_path = jax.lax.scan( viterbi_backward, final_state, most_likely_sources[1:], reverse=True) return jnp.append(most_likely_path, final_state)
(init_dist: Union[distrax._src.distributions.categorical.Categorical, tensorflow_probability.substrates.jax.distributions.categorical.Categorical], trans_dist: Union[distrax._src.distributions.categorical.Categorical, tensorflow_probability.substrates.jax.distributions.categorical.Categorical], obs_dist: Union[distrax._src.distributions.distribution.Distribution, tensorflow_probability.substrates.jax.distributions.distribution.Distribution])
55,776
distrax._src.utils.hmm
__init__
Constructs an N-state Hidden Markov Model from component distributions. Args: init_dist: Integer-valued categorical distribution with parameters of shape (N,), representing the distribution over initial latent states. trans_dist: Integer-valued categorical distribution with parameters of shape (N, N), representing the transition probability matrix between latent states. obs_dist: Any observation distribution with batch shape (N,), representing `p(observation|latent state)`.
def __init__(self, init_dist: categorical.CategoricalLike, trans_dist: categorical.CategoricalLike, obs_dist: distribution.DistributionLike): """Constructs an N-state Hidden Markov Model from component distributions. Args: init_dist: Integer-valued categorical distribution with parameters of shape (N,), representing the distribution over initial latent states. trans_dist: Integer-valued categorical distribution with parameters of shape (N, N), representing the transition probability matrix between latent states. obs_dist: Any observation distribution with batch shape (N,), representing `p(observation|latent state)`. """ self._init_dist = conversion.as_distribution(init_dist) self._trans_dist = conversion.as_distribution(trans_dist) self._obs_dist = conversion.as_distribution(obs_dist) self._n_states = self._init_dist.num_categories if not jnp.issubdtype(self._init_dist.dtype, jnp.integer): raise TypeError( f'init_dist must be categorical-like with integer dtype, but its ' f'dtype is {self._init_dist.dtype}.') if not jnp.issubdtype(self._trans_dist.dtype, jnp.integer): raise TypeError( f'trans_dist must be categorical-like with integer dtype, but its ' f'dtype is {self._trans_dist.dtype}.') if self._init_dist.batch_shape: raise ValueError( f'init_dist must be unbatched, but it has a batch shape of ' f'{self._init_dist.batch_shape}.') if self._obs_dist.batch_shape != (self._n_states,): raise ValueError( f'obs_dist should have batch shape of ({self._n_states},) equal to ' f'the number of latent states in the model, but its batch shape is ' f'{self._obs_dist.batch_shape}.') if self._trans_dist.batch_shape != (self._n_states,): raise ValueError( f'trans_dist should have batch shape of ({self._n_states},) equal to ' f'the number of latent states in the model, but its batch shape is ' f'{self._trans_dist.batch_shape}.') if self._trans_dist.num_categories != self._n_states: raise ValueError( f'trans_dist should have `num_categories` of {self._n_states} equal ' f'to the number of latent states in the model, but it has ' f'`num_categories` of {self._trans_dist.num_categories}.')
(self, init_dist: Union[distrax._src.distributions.categorical.Categorical, tensorflow_probability.substrates.jax.distributions.categorical.Categorical], trans_dist: Union[distrax._src.distributions.categorical.Categorical, tensorflow_probability.substrates.jax.distributions.categorical.Categorical], obs_dist: Union[distrax._src.distributions.distribution.Distribution, tensorflow_probability.substrates.jax.distributions.distribution.Distribution])
55,778
distrax._src.utils.hmm
backward
Computes the backward probabilities. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Array of backward joint probabilities `p(x_{t+1:T}|z_t)`.
def backward(self, obs_seq: chex.Array, length: Optional[chex.Array] = None) -> chex.Array: """Computes the backward probabilities. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Array of backward joint probabilities `p(x_{t+1:T}|z_t)`. """ seq_len = len(obs_seq) if length is None: length = seq_len beta_t = jnp.ones((self._n_states,)) def scan_fn(beta_prev, t): beta_t = jnp.where( t > length, jnp.zeros_like(beta_prev), _normalize((beta_prev * self._obs_dist.prob(obs_seq[t-1]) * self._trans_dist.probs).sum(axis=1))[0]) return beta_t, beta_t ts = jnp.arange(seq_len, 1, -1) _, beta_hist = jax.lax.scan(scan_fn, beta_t, ts) beta_hist = jnp.flip( jnp.vstack([beta_t.reshape(1, self._n_states), beta_hist]), axis=0) return beta_hist
(self, obs_seq: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], length: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, NoneType] = None) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,779
distrax._src.utils.hmm
forward
Calculates a belief state. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of `log(p(x_{1:T}|model))` and the array of forward joint probabilities `p(z_t,x_{1:t})` for each sample `x_t`.
def forward(self, obs_seq: chex.Array, length: Optional[chex.Array] = None) -> Tuple[float, chex.Array]: """Calculates a belief state. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of `log(p(x_{1:T}|model))` and the array of forward joint probabilities `p(z_t,x_{1:t})` for each sample `x_t`. """ seq_len = len(obs_seq) if length is None: length = seq_len def scan_fn(carry, t): (alpha_prev, log_ll_prev) = carry alpha_n = jnp.where( t < length, (self._obs_dist.prob(obs_seq[t]) * (alpha_prev[:, None] * self._trans_dist.probs).sum(axis=0)), jnp.zeros_like(alpha_prev)) alpha_n, cn = _normalize(alpha_n) carry = (alpha_n, jnp.log(cn) + log_ll_prev) return carry, alpha_n # initial belief state alpha_0, c0 = _normalize( self._init_dist.probs * self._obs_dist.prob(obs_seq[0])) # setup scan loop init_state = (alpha_0, jnp.log(c0)) ts = jnp.arange(1, seq_len) carry, alpha_hist = jax.lax.scan(scan_fn, init_state, ts) # post-process alpha_hist = jnp.vstack([alpha_0.reshape(1, self._n_states), alpha_hist]) (_, log_ll) = carry return log_ll, alpha_hist
(self, obs_seq: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], length: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, NoneType] = None) -> Tuple[float, Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,780
distrax._src.utils.hmm
forward_backward
HMM forward-backward algorithm. Computes, for each time step, the marginal conditional probability that the Hidden Markov Model was in each possible state given the observations that were made at each time step, i.e. P(z[i] | x[0], ..., x[num_steps - 1]) for all i from 0 to num_steps - 1. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of: * Forward joint probabilities `p(z_t,x_{1:t})`. * Backward joint probabilities `p(x_{t+1:T}|z_t)`. * Marginal conditional probability of the observations. * The log-likelihood log(p(x_{1:T}|model)).
def forward_backward( self, obs_seq: chex.Array, length: Optional[chex.Array] = None, ) -> Tuple[chex.Array, chex.Array, chex.Array, float]: """HMM forward-backward algorithm. Computes, for each time step, the marginal conditional probability that the Hidden Markov Model was in each possible state given the observations that were made at each time step, i.e. P(z[i] | x[0], ..., x[num_steps - 1]) for all i from 0 to num_steps - 1. Args: obs_seq: Observation sequence. length: The valid length of the observation sequence, used to truncate the computation for batches of varying length. If set to None, the entire sequence is used. Returns: Tuple of: * Forward joint probabilities `p(z_t,x_{1:t})`. * Backward joint probabilities `p(x_{t+1:T}|z_t)`. * Marginal conditional probability of the observations. * The log-likelihood log(p(x_{1:T}|model)). """ seq_len = len(obs_seq) if length is None: length = seq_len def gamma_t(t): return alpha[t] * beta[t] ll, alpha = self.forward(obs_seq, length) beta = self.backward(obs_seq, length) ts = jnp.arange(seq_len) gamma = jax.vmap(gamma_t)(ts) gamma = jax.vmap(lambda x: _normalize(x)[0])(gamma) return alpha, beta, gamma, ll
(self, obs_seq: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], length: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, NoneType] = None) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], float]
55,781
distrax._src.utils.hmm
sample
Sample from this HMM. Samples an observation of given length according to this Hidden Markov Model and gives the sequence of the hidden states as well as the observation. Args: seed: Random key of shape (2,) and dtype uint32. seq_len: The length of the observation sequence. Returns: Tuple of hidden state sequence, and observation sequence.
def sample(self, *, seed: chex.PRNGKey, seq_len: int) -> Tuple[chex.Array, chex.Array]: """Sample from this HMM. Samples an observation of given length according to this Hidden Markov Model and gives the sequence of the hidden states as well as the observation. Args: seed: Random key of shape (2,) and dtype uint32. seq_len: The length of the observation sequence. Returns: Tuple of hidden state sequence, and observation sequence. """ rng_key, rng_init = jax.random.split(seed) initial_state = self._init_dist.sample(seed=rng_init) def draw_state(prev_state, key): state = self._trans_dist.sample(seed=key)[prev_state] return state, state rng_state, rng_obs = jax.random.split(rng_key) keys = jax.random.split(rng_state, seq_len - 1) _, states = jax.lax.scan(draw_state, initial_state, keys) states = jnp.append(initial_state, states) def draw_obs(state, key): return self._obs_dist.sample(seed=key)[state] keys = jax.random.split(rng_obs, seq_len) obs_seq = jax.vmap(draw_obs, in_axes=(0, 0))(states, keys) return states, obs_seq
(self, *, seed: jax.Array, seq_len: int) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,783
distrax._src.utils.hmm
viterbi
Viterbi algorithm. Computes the most probable sequence of hidden states given the observations. Args: obs_seq: Observation sequence. Returns: The most probable sequence of hidden states.
def viterbi(self, obs_seq: chex.Array) -> chex.Array: """Viterbi algorithm. Computes the most probable sequence of hidden states given the observations. Args: obs_seq: Observation sequence. Returns: The most probable sequence of hidden states. """ trans_log_probs = jax.nn.log_softmax(self._trans_dist.logits) init_log_probs = jax.nn.log_softmax(self._init_dist.logits) first_log_prob = init_log_probs + self._obs_dist.log_prob(obs_seq[0]) if len(obs_seq) == 1: return jnp.expand_dims(jnp.argmax(first_log_prob), axis=0) def viterbi_forward(prev_logp, obs): obs_logp = self._obs_dist.log_prob(obs) logp = prev_logp[..., None] + trans_log_probs + obs_logp[..., None, :] max_logp_given_successor = jnp.max(logp, axis=-2) most_likely_given_successor = jnp.argmax(logp, axis=-2) return max_logp_given_successor, most_likely_given_successor final_log_prob, most_likely_sources = jax.lax.scan( viterbi_forward, first_log_prob, obs_seq[1:]) most_likely_initial_given_successor = jnp.argmax( trans_log_probs + first_log_prob, axis=-2) most_likely_sources = jnp.concatenate([ jnp.expand_dims(most_likely_initial_given_successor, axis=0), most_likely_sources], axis=0) def viterbi_backward(state, most_likely_sources): state = jax.nn.one_hot(state, self._n_states) most_likely = jnp.sum(most_likely_sources * state).astype(jnp.int64) return most_likely, most_likely final_state = jnp.argmax(final_log_prob) _, most_likely_path = jax.lax.scan( viterbi_backward, final_state, most_likely_sources[1:], reverse=True) return jnp.append(most_likely_path, final_state)
(self, obs_seq: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,784
distrax._src.distributions.independent
Independent
Independent distribution obtained from child distributions.
class Independent(distrax_distribution.Distribution): """Independent distribution obtained from child distributions.""" equiv_tfp_cls = tfd.Independent def __init__(self, distribution: DistributionLike, reinterpreted_batch_ndims: Optional[int] = None): """Initializes an Independent distribution. Args: distribution: Base distribution instance. reinterpreted_batch_ndims: Number of event dimensions. """ super().__init__() distribution = conversion.as_distribution(distribution) self._distribution = distribution # Check if event shape is a tuple of integers (i.e. not nested). event_shape = distribution.event_shape if not (isinstance(event_shape, tuple) and all(isinstance(i, int) for i in event_shape)): raise ValueError( f"'Independent' currently only supports distributions with Array " f"events (i.e. not nested). Received '{distribution.name}' with " f"event shape '{distribution.event_shape}'.") dist_batch_shape = distribution.batch_shape if reinterpreted_batch_ndims is not None: dist_batch_ndims = len(dist_batch_shape) if reinterpreted_batch_ndims > dist_batch_ndims: raise ValueError( f'`reinterpreted_batch_ndims` is {reinterpreted_batch_ndims}, but' f' distribution `{distribution.name}` has only {dist_batch_ndims}' f' batch dimensions.') elif reinterpreted_batch_ndims < 0: raise ValueError(f'`reinterpreted_batch_ndims` can\'t be negative; got' f' {reinterpreted_batch_ndims}.') self._reinterpreted_batch_ndims = reinterpreted_batch_ndims else: self._reinterpreted_batch_ndims = max(len(dist_batch_shape) - 1, 0) @property def event_shape(self) -> Tuple[int, ...]: """Shape of event of distribution samples.""" dist_batch_shape = self._distribution.batch_shape event_ndims = len(dist_batch_shape) - self._reinterpreted_batch_ndims return dist_batch_shape[event_ndims:] + self._distribution.event_shape @property def distribution(self): return self._distribution @property def reinterpreted_batch_ndims(self) -> int: return self._reinterpreted_batch_ndims @property def batch_shape(self) -> Tuple[int, ...]: """Shape of batch of distribution samples.""" dist_batch_shape = self._distribution.batch_shape d = len(dist_batch_shape) - self.reinterpreted_batch_ndims return dist_batch_shape[:d] def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" return self._distribution.sample(seed=key, sample_shape=n) def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" samples, log_prob = self._distribution.sample_and_log_prob( seed=key, sample_shape=n) log_prob = self._reduce(jnp.sum, log_prob) return samples, log_prob def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" return self._reduce(jnp.sum, self._distribution.log_prob(value)) def entropy(self) -> Array: """See `Distribution.entropy`.""" return self._reduce(jnp.sum, self._distribution.entropy()) def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" return self._reduce(jnp.sum, self._distribution.log_cdf(value)) def mean(self) -> Array: """Calculates the mean.""" return self._distribution.mean() def median(self) -> Array: """Calculates the median.""" return self._distribution.median() def variance(self) -> Array: """Calculates the variance.""" return self._distribution.variance() def stddev(self) -> Array: """Calculates the standard deviation.""" return self._distribution.stddev() def mode(self) -> Array: """Calculates the mode.""" return self._distribution.mode() def _reduce(self, fn: Callable[..., Array], value: Array) -> Array: return fn(value, axis=[-i - 1 for i in range(0, self.reinterpreted_batch_ndims)]) def __getitem__(self, index) -> 'Independent': """See `Distribution.__getitem__`.""" index = distrax_distribution.to_batch_shape_index(self.batch_shape, index) return Independent( distribution=self.distribution[index], reinterpreted_batch_ndims=self.reinterpreted_batch_ndims)
(distribution: Union[distrax._src.distributions.distribution.Distribution, tensorflow_probability.substrates.jax.distributions.distribution.Distribution], reinterpreted_batch_ndims: Optional[int] = None)
55,785
distrax._src.distributions.independent
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Independent': """See `Distribution.__getitem__`.""" index = distrax_distribution.to_batch_shape_index(self.batch_shape, index) return Independent( distribution=self.distribution[index], reinterpreted_batch_ndims=self.reinterpreted_batch_ndims)
(self, index) -> distrax._src.distributions.independent.Independent
55,786
distrax._src.distributions.independent
__init__
Initializes an Independent distribution. Args: distribution: Base distribution instance. reinterpreted_batch_ndims: Number of event dimensions.
def __init__(self, distribution: DistributionLike, reinterpreted_batch_ndims: Optional[int] = None): """Initializes an Independent distribution. Args: distribution: Base distribution instance. reinterpreted_batch_ndims: Number of event dimensions. """ super().__init__() distribution = conversion.as_distribution(distribution) self._distribution = distribution # Check if event shape is a tuple of integers (i.e. not nested). event_shape = distribution.event_shape if not (isinstance(event_shape, tuple) and all(isinstance(i, int) for i in event_shape)): raise ValueError( f"'Independent' currently only supports distributions with Array " f"events (i.e. not nested). Received '{distribution.name}' with " f"event shape '{distribution.event_shape}'.") dist_batch_shape = distribution.batch_shape if reinterpreted_batch_ndims is not None: dist_batch_ndims = len(dist_batch_shape) if reinterpreted_batch_ndims > dist_batch_ndims: raise ValueError( f'`reinterpreted_batch_ndims` is {reinterpreted_batch_ndims}, but' f' distribution `{distribution.name}` has only {dist_batch_ndims}' f' batch dimensions.') elif reinterpreted_batch_ndims < 0: raise ValueError(f'`reinterpreted_batch_ndims` can\'t be negative; got' f' {reinterpreted_batch_ndims}.') self._reinterpreted_batch_ndims = reinterpreted_batch_ndims else: self._reinterpreted_batch_ndims = max(len(dist_batch_shape) - 1, 0)
(self, distribution: Union[distrax._src.distributions.distribution.Distribution, tensorflow_probability.substrates.jax.distributions.distribution.Distribution], reinterpreted_batch_ndims: Optional[int] = None)
55,789
distrax._src.distributions.independent
_reduce
null
def _reduce(self, fn: Callable[..., Array], value: Array) -> Array: return fn(value, axis=[-i - 1 for i in range(0, self.reinterpreted_batch_ndims)])
(self, fn: Callable[..., Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], value: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,790
distrax._src.distributions.independent
_sample_n
See `Distribution._sample_n`.
def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" return self._distribution.sample(seed=key, sample_shape=n)
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,791
distrax._src.distributions.independent
_sample_n_and_log_prob
See `Distribution._sample_n_and_log_prob`.
def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" samples, log_prob = self._distribution.sample_and_log_prob( seed=key, sample_shape=n) log_prob = self._reduce(jnp.sum, log_prob) return samples, log_prob
(self, key: jax.Array, n: int) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,794
distrax._src.distributions.independent
entropy
See `Distribution.entropy`.
def entropy(self) -> Array: """See `Distribution.entropy`.""" return self._reduce(jnp.sum, self._distribution.entropy())
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,796
distrax._src.distributions.independent
log_cdf
See `Distribution.log_cdf`.
def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" return self._reduce(jnp.sum, self._distribution.log_cdf(value))
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,797
distrax._src.distributions.independent
log_prob
See `Distribution.log_prob`.
def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" return self._reduce(jnp.sum, self._distribution.log_prob(value))
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,799
distrax._src.distributions.independent
mean
Calculates the mean.
def mean(self) -> Array: """Calculates the mean.""" return self._distribution.mean()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,800
distrax._src.distributions.independent
median
Calculates the median.
def median(self) -> Array: """Calculates the median.""" return self._distribution.median()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,801
distrax._src.distributions.independent
mode
Calculates the mode.
def mode(self) -> Array: """Calculates the mode.""" return self._distribution.mode()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,805
distrax._src.distributions.independent
stddev
Calculates the standard deviation.
def stddev(self) -> Array: """Calculates the standard deviation.""" return self._distribution.stddev()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,808
distrax._src.distributions.independent
variance
Calculates the variance.
def variance(self) -> Array: """Calculates the variance.""" return self._distribution.variance()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,809
distrax._src.bijectors.inverse
Inverse
A bijector that inverts a given bijector. That is, if `bijector` implements the transformation `f`, `Inverse(bijector)` implements the inverse transformation `f^{-1}`. The inversion is performed by swapping the forward with the corresponding inverse methods of the given bijector.
class Inverse(base.Bijector): """A bijector that inverts a given bijector. That is, if `bijector` implements the transformation `f`, `Inverse(bijector)` implements the inverse transformation `f^{-1}`. The inversion is performed by swapping the forward with the corresponding inverse methods of the given bijector. """ def __init__(self, bijector: BijectorLike): """Initializes an Inverse bijector. Args: bijector: the bijector to be inverted. It can be a distrax bijector, a TFP bijector, or a callable to be wrapped by `Lambda`. """ self._bijector = conversion.as_bijector(bijector) super().__init__( event_ndims_in=self._bijector.event_ndims_out, event_ndims_out=self._bijector.event_ndims_in, is_constant_jacobian=self._bijector.is_constant_jacobian, is_constant_log_det=self._bijector.is_constant_log_det) @property def bijector(self) -> BijectorT: """The base bijector that was the input to `Inverse`.""" return self._bijector def forward(self, x: Array) -> Array: """Computes y = f(x).""" return self._bijector.inverse(x) def inverse(self, y: Array) -> Array: """Computes x = f^{-1}(y).""" return self._bijector.forward(y) def forward_log_det_jacobian(self, x: Array) -> Array: """Computes log|det J(f)(x)|.""" return self._bijector.inverse_log_det_jacobian(x) def inverse_log_det_jacobian(self, y: Array) -> Array: """Computes log|det J(f^{-1})(y)|.""" return self._bijector.forward_log_det_jacobian(y) def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" return self._bijector.inverse_and_log_det(x) def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" return self._bijector.forward_and_log_det(y) @property def name(self) -> str: """Name of the bijector.""" return self.__class__.__name__ + self._bijector.name def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" if type(other) is Inverse: # pylint: disable=unidiomatic-typecheck return self.bijector.same_as(other.bijector) return False
(bijector: Union[distrax._src.bijectors.bijector.Bijector, tensorflow_probability.substrates.jax.bijectors.bijector.Bijector, Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]])
55,810
distrax._src.bijectors.inverse
__init__
Initializes an Inverse bijector. Args: bijector: the bijector to be inverted. It can be a distrax bijector, a TFP bijector, or a callable to be wrapped by `Lambda`.
def __init__(self, bijector: BijectorLike): """Initializes an Inverse bijector. Args: bijector: the bijector to be inverted. It can be a distrax bijector, a TFP bijector, or a callable to be wrapped by `Lambda`. """ self._bijector = conversion.as_bijector(bijector) super().__init__( event_ndims_in=self._bijector.event_ndims_out, event_ndims_out=self._bijector.event_ndims_in, is_constant_jacobian=self._bijector.is_constant_jacobian, is_constant_log_det=self._bijector.is_constant_log_det)
(self, bijector: Union[distrax._src.bijectors.bijector.Bijector, tensorflow_probability.substrates.jax.bijectors.bijector.Bijector, Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]])
55,814
distrax._src.bijectors.inverse
forward
Computes y = f(x).
def forward(self, x: Array) -> Array: """Computes y = f(x).""" return self._bijector.inverse(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,815
distrax._src.bijectors.inverse
forward_and_log_det
Computes y = f(x) and log|det J(f)(x)|.
def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" return self._bijector.inverse_and_log_det(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,816
distrax._src.bijectors.inverse
forward_log_det_jacobian
Computes log|det J(f)(x)|.
def forward_log_det_jacobian(self, x: Array) -> Array: """Computes log|det J(f)(x)|.""" return self._bijector.inverse_log_det_jacobian(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,817
distrax._src.bijectors.inverse
inverse
Computes x = f^{-1}(y).
def inverse(self, y: Array) -> Array: """Computes x = f^{-1}(y).""" return self._bijector.forward(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,818
distrax._src.bijectors.inverse
inverse_and_log_det
Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.
def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" return self._bijector.forward_and_log_det(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,819
distrax._src.bijectors.inverse
inverse_log_det_jacobian
Computes log|det J(f^{-1})(y)|.
def inverse_log_det_jacobian(self, y: Array) -> Array: """Computes log|det J(f^{-1})(y)|.""" return self._bijector.forward_log_det_jacobian(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,820
distrax._src.bijectors.inverse
same_as
Returns True if this bijector is guaranteed to be the same as `other`.
def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" if type(other) is Inverse: # pylint: disable=unidiomatic-typecheck return self.bijector.same_as(other.bijector) return False
(self, other: distrax._src.bijectors.bijector.Bijector) -> bool
55,822
distrax._src.distributions.joint
Joint
Joint distribution over a tree of statistically independent distributions. Samples from the Joint distribution take the form of a tree structure that matches the structure of the underlying distributions. Log-probabilities are summed over the tree. All distributions in the tree must have the same `batch_shape` in order for log-probabilities to be computed correctly and for the `batch_shape` of the Joint distribution to be correct.
class Joint(distribution.Distribution): """Joint distribution over a tree of statistically independent distributions. Samples from the Joint distribution take the form of a tree structure that matches the structure of the underlying distributions. Log-probabilities are summed over the tree. All distributions in the tree must have the same `batch_shape` in order for log-probabilities to be computed correctly and for the `batch_shape` of the Joint distribution to be correct. """ def __init__(self, distributions: DistributionT): """Initializes a Joint distribution over a tree of distributions. Args: distributions: Tree of distributions that must have the same batch shape. """ super().__init__() self._distributions = tree.map_structure(conversion.as_distribution, distributions) batch_shape = None first_path = None for path, dist in tree.flatten_with_path(self._distributions): batch_shape = batch_shape or dist.batch_shape first_path = '.'.join(map(str, path)) if dist.batch_shape != batch_shape: path = '.'.join(map(str, path)) raise ValueError( f'Joint distributions must have the same batch shape, but ' f'distribution "{dist.name}" at location {path} had batch shape ' f'{dist.batch_shape} which is not equal to the batch shape ' f'{batch_shape} of the distribution at location {first_path}.') def _sample_n( self, key: chex.PRNGKey, n: int) -> distribution.EventT: keys = list(jax.random.split(key, len(tree.flatten(self._distributions)))) keys = tree.unflatten_as(self._distributions, keys) return tree.map_structure(lambda d, k: d.sample(seed=k, sample_shape=n), self._distributions, keys) def _sample_n_and_log_prob( self, key: chex.PRNGKey, n: int) -> Tuple[distribution.EventT, chex.Array]: keys = list(jax.random.split(key, len(tree.flatten(self._distributions)))) keys = tree.unflatten_as(self._distributions, keys) samples_and_log_probs = tree.map_structure( lambda d, k: d.sample_and_log_prob(seed=k, sample_shape=n), self._distributions, keys) samples = tree.map_structure_up_to( self._distributions, lambda p: p[0], samples_and_log_probs) log_probs = tree.map_structure_up_to( self._distributions, lambda p: p[1], samples_and_log_probs) log_probs = jnp.stack(tree.flatten(log_probs)) log_probs = jnp.sum(log_probs, axis=0) return samples, log_probs def log_prob(self, value: distribution.EventT) -> chex.Array: """Compute the total log probability of the distributions in the tree.""" log_probs = tree.map_structure(lambda dist, value: dist.log_prob(value), self._distributions, value) log_probs = jnp.stack(tree.flatten(log_probs)) return jnp.sum(log_probs, axis=0) @property def distributions(self) -> DistributionT: return self._distributions @property def event_shape(self) -> distribution.ShapeT: return tree.map_structure(lambda dist: dist.event_shape, self._distributions) @property def batch_shape(self) -> Tuple[int, ...]: return tree.flatten(self._distributions)[0].batch_shape @property def dtype(self) -> distribution.DTypeT: return tree.map_structure(lambda dist: dist.dtype, self._distributions) def entropy(self) -> chex.Array: return sum(dist.entropy() for dist in tree.flatten(self._distributions)) def log_cdf(self, value: distribution.EventT) -> chex.Array: return sum(dist.log_cdf(v) for dist, v in zip(tree.flatten(self._distributions), tree.flatten(value))) def mean(self) -> distribution.EventT: """Calculates the mean.""" return tree.map_structure(lambda dist: dist.mean(), self._distributions) def median(self) -> distribution.EventT: """Calculates the median.""" return tree.map_structure(lambda dist: dist.median(), self._distributions) def mode(self) -> distribution.EventT: """Calculates the mode.""" return tree.map_structure(lambda dist: dist.mode(), self._distributions) def __getitem__(self, index) -> 'Joint': """See `Distribution.__getitem__`.""" return Joint(tree.map_structure(lambda dist: dist[index], self._distributions))
(distributions: ~DistributionT)
55,823
distrax._src.distributions.joint
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Joint': """See `Distribution.__getitem__`.""" return Joint(tree.map_structure(lambda dist: dist[index], self._distributions))
(self, index) -> distrax._src.distributions.joint.Joint
55,824
distrax._src.distributions.joint
__init__
Initializes a Joint distribution over a tree of distributions. Args: distributions: Tree of distributions that must have the same batch shape.
def __init__(self, distributions: DistributionT): """Initializes a Joint distribution over a tree of distributions. Args: distributions: Tree of distributions that must have the same batch shape. """ super().__init__() self._distributions = tree.map_structure(conversion.as_distribution, distributions) batch_shape = None first_path = None for path, dist in tree.flatten_with_path(self._distributions): batch_shape = batch_shape or dist.batch_shape first_path = '.'.join(map(str, path)) if dist.batch_shape != batch_shape: path = '.'.join(map(str, path)) raise ValueError( f'Joint distributions must have the same batch shape, but ' f'distribution "{dist.name}" at location {path} had batch shape ' f'{dist.batch_shape} which is not equal to the batch shape ' f'{batch_shape} of the distribution at location {first_path}.')
(self, distributions: ~DistributionT)
55,827
distrax._src.distributions.joint
_sample_n
null
def _sample_n( self, key: chex.PRNGKey, n: int) -> distribution.EventT: keys = list(jax.random.split(key, len(tree.flatten(self._distributions)))) keys = tree.unflatten_as(self._distributions, keys) return tree.map_structure(lambda d, k: d.sample(seed=k, sample_shape=n), self._distributions, keys)
(self, key: jax.Array, n: int) -> ~EventT
55,828
distrax._src.distributions.joint
_sample_n_and_log_prob
null
def _sample_n_and_log_prob( self, key: chex.PRNGKey, n: int) -> Tuple[distribution.EventT, chex.Array]: keys = list(jax.random.split(key, len(tree.flatten(self._distributions)))) keys = tree.unflatten_as(self._distributions, keys) samples_and_log_probs = tree.map_structure( lambda d, k: d.sample_and_log_prob(seed=k, sample_shape=n), self._distributions, keys) samples = tree.map_structure_up_to( self._distributions, lambda p: p[0], samples_and_log_probs) log_probs = tree.map_structure_up_to( self._distributions, lambda p: p[1], samples_and_log_probs) log_probs = jnp.stack(tree.flatten(log_probs)) log_probs = jnp.sum(log_probs, axis=0) return samples, log_probs
(self, key: jax.Array, n: int) -> Tuple[~EventT, Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,831
distrax._src.distributions.joint
entropy
null
def entropy(self) -> chex.Array: return sum(dist.entropy() for dist in tree.flatten(self._distributions))
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,833
distrax._src.distributions.joint
log_cdf
null
def log_cdf(self, value: distribution.EventT) -> chex.Array: return sum(dist.log_cdf(v) for dist, v in zip(tree.flatten(self._distributions), tree.flatten(value)))
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,834
distrax._src.distributions.joint
log_prob
Compute the total log probability of the distributions in the tree.
def log_prob(self, value: distribution.EventT) -> chex.Array: """Compute the total log probability of the distributions in the tree.""" log_probs = tree.map_structure(lambda dist, value: dist.log_prob(value), self._distributions, value) log_probs = jnp.stack(tree.flatten(log_probs)) return jnp.sum(log_probs, axis=0)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,836
distrax._src.distributions.joint
mean
Calculates the mean.
def mean(self) -> distribution.EventT: """Calculates the mean.""" return tree.map_structure(lambda dist: dist.mean(), self._distributions)
(self) -> ~EventT
55,837
distrax._src.distributions.joint
median
Calculates the median.
def median(self) -> distribution.EventT: """Calculates the median.""" return tree.map_structure(lambda dist: dist.median(), self._distributions)
(self) -> ~EventT
55,838
distrax._src.distributions.joint
mode
Calculates the mode.
def mode(self) -> distribution.EventT: """Calculates the mode.""" return tree.map_structure(lambda dist: dist.mode(), self._distributions)
(self) -> ~EventT
55,846
distrax._src.bijectors.lambda_bijector
Lambda
Wrapper to automatically turn JAX functions into fully fledged bijectors. This class takes in JAX functions that implement bijector methods (such as `forward`, `inverse`, `forward_log_det_jacobian`, etc.), and constructs a bijector out of them. Any functions not explicitly specified by the user will be automatically derived from the existing functions where possible, by tracing their JAXPR representation. Missing functions will be derived on demand: if a missing function is not used, it will not be derived. At a minimum, either `forward` or `inverse` must be given; all other methods will be derived (where possible). The Lambda bijector can be useful for creating simple one-line bijectors that would otherwise be tedious to define. Examples of scalar bijectors that can be easily constructed with Lambda are: - Identity: `Lambda(lambda x: x)` - Affine: `Lambda(lambda x: a*x + b)` - Tanh: `Lambda(jnp.tanh)` - Composite: `Lambda(lambda x: jnp.tanh(a*x + b))` Requirements and limitations: - Only functions composed entirely of invertible primitives can be automatically inverted (see `bijection_utils.py` for a list of invertible primitives). If the inverse is needed but is not automatically derivable, the user must provide it explicitly. - If log-determinant functions are not provided, Lambda will assume that `forward` and `inverse` are scalar functions applied elementwise. If the bijector is not meant to be scalar, its log-determinant functions must be provided explicitly by the user.
class Lambda(base.Bijector): """Wrapper to automatically turn JAX functions into fully fledged bijectors. This class takes in JAX functions that implement bijector methods (such as `forward`, `inverse`, `forward_log_det_jacobian`, etc.), and constructs a bijector out of them. Any functions not explicitly specified by the user will be automatically derived from the existing functions where possible, by tracing their JAXPR representation. Missing functions will be derived on demand: if a missing function is not used, it will not be derived. At a minimum, either `forward` or `inverse` must be given; all other methods will be derived (where possible). The Lambda bijector can be useful for creating simple one-line bijectors that would otherwise be tedious to define. Examples of scalar bijectors that can be easily constructed with Lambda are: - Identity: `Lambda(lambda x: x)` - Affine: `Lambda(lambda x: a*x + b)` - Tanh: `Lambda(jnp.tanh)` - Composite: `Lambda(lambda x: jnp.tanh(a*x + b))` Requirements and limitations: - Only functions composed entirely of invertible primitives can be automatically inverted (see `bijection_utils.py` for a list of invertible primitives). If the inverse is needed but is not automatically derivable, the user must provide it explicitly. - If log-determinant functions are not provided, Lambda will assume that `forward` and `inverse` are scalar functions applied elementwise. If the bijector is not meant to be scalar, its log-determinant functions must be provided explicitly by the user. """ def __init__( self, forward: Optional[Callable[[Array], Array]] = None, inverse: Optional[Callable[[Array], Array]] = None, forward_log_det_jacobian: Optional[Callable[[Array], Array]] = None, inverse_log_det_jacobian: Optional[Callable[[Array], Array]] = None, event_ndims_in: Optional[int] = None, event_ndims_out: Optional[int] = None, is_constant_jacobian: Optional[bool] = None): """Initializes a Lambda bijector with methods specified as args.""" if forward is None and inverse is None: raise ValueError("The Lambda bijector requires at least one of `forward` " "or `inverse` to be specified, but neither is.") jac_functions_specified = (forward_log_det_jacobian is not None or inverse_log_det_jacobian is not None) if jac_functions_specified: if event_ndims_in is None: raise ValueError("When log det Jacobian functions are specified, you " "must also specify `event_ndims_in`.") else: if event_ndims_in is not None or event_ndims_out is not None: raise ValueError("When log det Jacobian functions are unspecified, you " "must leave `event_ndims_in` and `event_ndims_out` " "unspecified; they will default to 0.") event_ndims_in = 0 if is_constant_jacobian is None: fn = inverse if forward is None else forward is_constant_jacobian = transformations.is_constant_jacobian(fn) super().__init__( event_ndims_in=event_ndims_in, event_ndims_out=event_ndims_out, is_constant_jacobian=is_constant_jacobian) self._forward = forward self._inverse = inverse self._forward_log_det_jacobian = forward_log_det_jacobian self._inverse_log_det_jacobian = inverse_log_det_jacobian def forward(self, x: Array) -> Array: """Computes y = f(x).""" self._check_forward_input_shape(x) if self._forward is None: self._forward = transformations.inv(self._inverse) return self._forward(x) def inverse(self, y: Array) -> Array: """Computes x = f^{-1}(y).""" self._check_inverse_input_shape(y) if self._inverse is None: self._inverse = transformations.inv(self._forward) return self._inverse(y) def forward_log_det_jacobian(self, x: Array) -> Array: """Computes log|det J(f)(x)|.""" self._check_forward_input_shape(x) if self._forward_log_det_jacobian is None: self._forward_log_det_jacobian = transformations.log_det_scalar( self.forward) return self._forward_log_det_jacobian(x) def inverse_log_det_jacobian(self, y: Array) -> Array: """Computes log|det J(f^{-1})(y)|.""" self._check_inverse_input_shape(y) if self._inverse_log_det_jacobian is None: self._inverse_log_det_jacobian = transformations.log_det_scalar( self.inverse) return self._inverse_log_det_jacobian(y) def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" return self.forward(x), self.forward_log_det_jacobian(x) def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" return self.inverse(y), self.inverse_log_det_jacobian(y) def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" if type(other) is Lambda: # pylint: disable=unidiomatic-typecheck return all(( self.forward is other.forward, self.inverse is other.inverse, self.forward_log_det_jacobian is other.forward_log_det_jacobian, self.inverse_log_det_jacobian is other.inverse_log_det_jacobian, self.forward_and_log_det is other.forward_and_log_det, self.inverse_and_log_det is other.inverse_and_log_det, )) return False
(forward: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, inverse: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, forward_log_det_jacobian: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, inverse_log_det_jacobian: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, event_ndims_in: Optional[int] = None, event_ndims_out: Optional[int] = None, is_constant_jacobian: Optional[bool] = None)
55,847
distrax._src.bijectors.lambda_bijector
__init__
Initializes a Lambda bijector with methods specified as args.
def __init__( self, forward: Optional[Callable[[Array], Array]] = None, inverse: Optional[Callable[[Array], Array]] = None, forward_log_det_jacobian: Optional[Callable[[Array], Array]] = None, inverse_log_det_jacobian: Optional[Callable[[Array], Array]] = None, event_ndims_in: Optional[int] = None, event_ndims_out: Optional[int] = None, is_constant_jacobian: Optional[bool] = None): """Initializes a Lambda bijector with methods specified as args.""" if forward is None and inverse is None: raise ValueError("The Lambda bijector requires at least one of `forward` " "or `inverse` to be specified, but neither is.") jac_functions_specified = (forward_log_det_jacobian is not None or inverse_log_det_jacobian is not None) if jac_functions_specified: if event_ndims_in is None: raise ValueError("When log det Jacobian functions are specified, you " "must also specify `event_ndims_in`.") else: if event_ndims_in is not None or event_ndims_out is not None: raise ValueError("When log det Jacobian functions are unspecified, you " "must leave `event_ndims_in` and `event_ndims_out` " "unspecified; they will default to 0.") event_ndims_in = 0 if is_constant_jacobian is None: fn = inverse if forward is None else forward is_constant_jacobian = transformations.is_constant_jacobian(fn) super().__init__( event_ndims_in=event_ndims_in, event_ndims_out=event_ndims_out, is_constant_jacobian=is_constant_jacobian) self._forward = forward self._inverse = inverse self._forward_log_det_jacobian = forward_log_det_jacobian self._inverse_log_det_jacobian = inverse_log_det_jacobian
(self, forward: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, inverse: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, forward_log_det_jacobian: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, inverse_log_det_jacobian: Optional[Callable[[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]] = None, event_ndims_in: Optional[int] = None, event_ndims_out: Optional[int] = None, is_constant_jacobian: Optional[bool] = None)
55,851
distrax._src.bijectors.lambda_bijector
forward
Computes y = f(x).
def forward(self, x: Array) -> Array: """Computes y = f(x).""" self._check_forward_input_shape(x) if self._forward is None: self._forward = transformations.inv(self._inverse) return self._forward(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,852
distrax._src.bijectors.lambda_bijector
forward_and_log_det
Computes y = f(x) and log|det J(f)(x)|.
def forward_and_log_det(self, x: Array) -> Tuple[Array, Array]: """Computes y = f(x) and log|det J(f)(x)|.""" return self.forward(x), self.forward_log_det_jacobian(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,853
distrax._src.bijectors.lambda_bijector
forward_log_det_jacobian
Computes log|det J(f)(x)|.
def forward_log_det_jacobian(self, x: Array) -> Array: """Computes log|det J(f)(x)|.""" self._check_forward_input_shape(x) if self._forward_log_det_jacobian is None: self._forward_log_det_jacobian = transformations.log_det_scalar( self.forward) return self._forward_log_det_jacobian(x)
(self, x: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,854
distrax._src.bijectors.lambda_bijector
inverse
Computes x = f^{-1}(y).
def inverse(self, y: Array) -> Array: """Computes x = f^{-1}(y).""" self._check_inverse_input_shape(y) if self._inverse is None: self._inverse = transformations.inv(self._forward) return self._inverse(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,855
distrax._src.bijectors.lambda_bijector
inverse_and_log_det
Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.
def inverse_and_log_det(self, y: Array) -> Tuple[Array, Array]: """Computes x = f^{-1}(y) and log|det J(f^{-1})(y)|.""" return self.inverse(y), self.inverse_log_det_jacobian(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,856
distrax._src.bijectors.lambda_bijector
inverse_log_det_jacobian
Computes log|det J(f^{-1})(y)|.
def inverse_log_det_jacobian(self, y: Array) -> Array: """Computes log|det J(f^{-1})(y)|.""" self._check_inverse_input_shape(y) if self._inverse_log_det_jacobian is None: self._inverse_log_det_jacobian = transformations.log_det_scalar( self.inverse) return self._inverse_log_det_jacobian(y)
(self, y: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,857
distrax._src.bijectors.lambda_bijector
same_as
Returns True if this bijector is guaranteed to be the same as `other`.
def same_as(self, other: base.Bijector) -> bool: """Returns True if this bijector is guaranteed to be the same as `other`.""" if type(other) is Lambda: # pylint: disable=unidiomatic-typecheck return all(( self.forward is other.forward, self.inverse is other.inverse, self.forward_log_det_jacobian is other.forward_log_det_jacobian, self.inverse_log_det_jacobian is other.inverse_log_det_jacobian, self.forward_and_log_det is other.forward_and_log_det, self.inverse_and_log_det is other.inverse_and_log_det, )) return False
(self, other: distrax._src.bijectors.bijector.Bijector) -> bool
55,859
distrax._src.distributions.laplace
Laplace
Laplace distribution with location `loc` and `scale` parameters.
class Laplace(distribution.Distribution): """Laplace distribution with location `loc` and `scale` parameters.""" equiv_tfp_cls = tfd.Laplace def __init__(self, loc: Numeric, scale: Numeric): """Initializes a Laplace distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution. """ super().__init__() self._loc = conversion.as_float_array(loc) self._scale = conversion.as_float_array(scale) self._batch_shape = jax.lax.broadcast_shapes( self._loc.shape, self._scale.shape) @property def event_shape(self) -> Tuple[int, ...]: """Shape of event of distribution samples.""" return () @property def batch_shape(self) -> Tuple[int, ...]: """Shape of batch of distribution samples.""" return self._batch_shape @property def loc(self) -> Array: """Mean of the distribution.""" return jnp.broadcast_to(self._loc, self.batch_shape) @property def scale(self) -> Array: """Scale of the distribution.""" return jnp.broadcast_to(self._scale, self.batch_shape) def _sample_from_std_laplace(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._loc, self._scale) return jax.random.laplace(key, shape=out_shape, dtype=dtype) def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_laplace(key, n) return self._loc + self._scale * rnd def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" rnd = self._sample_from_std_laplace(key, n) samples = self._loc + self._scale * rnd log_prob = -jnp.abs(rnd) - math.log(2.) - jnp.log(self._scale) return samples, log_prob def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" norm_value = self._standardize(value) return -jnp.abs(norm_value) - math.log(2.) - jnp.log(self._scale) def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" return math.log(2.) + 1. + jnp.log(self.scale) def cdf(self, value: EventT) -> Array: """See `Distribution.cdf`.""" norm_value = self._standardize(value) return 0.5 - 0.5 * jnp.sign(norm_value) * jnp.expm1(-jnp.abs(norm_value)) def _standardize(self, value: Array) -> Array: return (value - self._loc) / self._scale def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" norm_value = self._standardize(value) return _log_cdf_laplace(norm_value) def log_survival_function(self, value: EventT) -> Array: """See `Distribution.log_survival_function`.""" norm_value = self._standardize(value) return _log_cdf_laplace(-norm_value) def mean(self) -> Array: """Calculates the mean.""" return self.loc def stddev(self) -> Array: """Calculates the standard deviation.""" return math.sqrt(2.) * self.scale def variance(self) -> Array: """Calculates the variance.""" return 2. * jnp.square(self.scale) def mode(self) -> Array: """Calculates the mode.""" return self.mean() def median(self) -> Array: """Calculates the median.""" return self.mean() def __getitem__(self, index) -> 'Laplace': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Laplace(loc=self.loc[index], scale=self.scale[index])
(loc: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], scale: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,860
distrax._src.distributions.laplace
__getitem__
See `Distribution.__getitem__`.
def __getitem__(self, index) -> 'Laplace': """See `Distribution.__getitem__`.""" index = distribution.to_batch_shape_index(self.batch_shape, index) return Laplace(loc=self.loc[index], scale=self.scale[index])
(self, index) -> distrax._src.distributions.laplace.Laplace
55,861
distrax._src.distributions.laplace
__init__
Initializes a Laplace distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution.
def __init__(self, loc: Numeric, scale: Numeric): """Initializes a Laplace distribution. Args: loc: Mean of the distribution. scale: Spread of the distribution. """ super().__init__() self._loc = conversion.as_float_array(loc) self._scale = conversion.as_float_array(scale) self._batch_shape = jax.lax.broadcast_shapes( self._loc.shape, self._scale.shape)
(self, loc: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int], scale: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number, float, int])
55,864
distrax._src.distributions.laplace
_sample_from_std_laplace
null
def _sample_from_std_laplace(self, key: PRNGKey, n: int) -> Array: out_shape = (n,) + self.batch_shape dtype = jnp.result_type(self._loc, self._scale) return jax.random.laplace(key, shape=out_shape, dtype=dtype)
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,865
distrax._src.distributions.laplace
_sample_n
See `Distribution._sample_n`.
def _sample_n(self, key: PRNGKey, n: int) -> Array: """See `Distribution._sample_n`.""" rnd = self._sample_from_std_laplace(key, n) return self._loc + self._scale * rnd
(self, key: jax.Array, n: int) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,866
distrax._src.distributions.laplace
_sample_n_and_log_prob
See `Distribution._sample_n_and_log_prob`.
def _sample_n_and_log_prob(self, key: PRNGKey, n: int) -> Tuple[Array, Array]: """See `Distribution._sample_n_and_log_prob`.""" rnd = self._sample_from_std_laplace(key, n) samples = self._loc + self._scale * rnd log_prob = -jnp.abs(rnd) - math.log(2.) - jnp.log(self._scale) return samples, log_prob
(self, key: jax.Array, n: int) -> Tuple[Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number], Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]]
55,867
distrax._src.distributions.laplace
_standardize
null
def _standardize(self, value: Array) -> Array: return (value - self._loc) / self._scale
(self, value: Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,868
distrax._src.distributions.laplace
cdf
See `Distribution.cdf`.
def cdf(self, value: EventT) -> Array: """See `Distribution.cdf`.""" norm_value = self._standardize(value) return 0.5 - 0.5 * jnp.sign(norm_value) * jnp.expm1(-jnp.abs(norm_value))
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,870
distrax._src.distributions.laplace
entropy
Calculates the Shannon entropy (in nats).
def entropy(self) -> Array: """Calculates the Shannon entropy (in nats).""" return math.log(2.) + 1. + jnp.log(self.scale)
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,872
distrax._src.distributions.laplace
log_cdf
See `Distribution.log_cdf`.
def log_cdf(self, value: EventT) -> Array: """See `Distribution.log_cdf`.""" norm_value = self._standardize(value) return _log_cdf_laplace(norm_value)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,873
distrax._src.distributions.laplace
log_prob
See `Distribution.log_prob`.
def log_prob(self, value: EventT) -> Array: """See `Distribution.log_prob`.""" norm_value = self._standardize(value) return -jnp.abs(norm_value) - math.log(2.) - jnp.log(self._scale)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,874
distrax._src.distributions.laplace
log_survival_function
See `Distribution.log_survival_function`.
def log_survival_function(self, value: EventT) -> Array: """See `Distribution.log_survival_function`.""" norm_value = self._standardize(value) return _log_cdf_laplace(-norm_value)
(self, value: ~EventT) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]
55,876
distrax._src.distributions.laplace
median
Calculates the median.
def median(self) -> Array: """Calculates the median.""" return self.mean()
(self) -> Union[jax.Array, numpy.ndarray, numpy.bool_, numpy.number]