diff --git "a/env-llmeval/lib/python3.10/site-packages/sympy/polys/polytools.py" "b/env-llmeval/lib/python3.10/site-packages/sympy/polys/polytools.py" new file mode 100644--- /dev/null +++ "b/env-llmeval/lib/python3.10/site-packages/sympy/polys/polytools.py" @@ -0,0 +1,7425 @@ +"""User-friendly public interface to polynomial functions. """ + + +from functools import wraps, reduce +from operator import mul +from typing import Optional + +from sympy.core import ( + S, Expr, Add, Tuple +) +from sympy.core.basic import Basic +from sympy.core.decorators import _sympifyit +from sympy.core.exprtools import Factors, factor_nc, factor_terms +from sympy.core.evalf import ( + pure_complex, evalf, fastlog, _evalf_with_bounded_error, quad_to_mpmath) +from sympy.core.function import Derivative +from sympy.core.mul import Mul, _keep_coeff +from sympy.core.numbers import ilcm, I, Integer, equal_valued +from sympy.core.relational import Relational, Equality +from sympy.core.sorting import ordered +from sympy.core.symbol import Dummy, Symbol +from sympy.core.sympify import sympify, _sympify +from sympy.core.traversal import preorder_traversal, bottom_up +from sympy.logic.boolalg import BooleanAtom +from sympy.polys import polyoptions as options +from sympy.polys.constructor import construct_domain +from sympy.polys.domains import FF, QQ, ZZ +from sympy.polys.domains.domainelement import DomainElement +from sympy.polys.fglmtools import matrix_fglm +from sympy.polys.groebnertools import groebner as _groebner +from sympy.polys.monomials import Monomial +from sympy.polys.orderings import monomial_key +from sympy.polys.polyclasses import DMP, DMF, ANP +from sympy.polys.polyerrors import ( + OperationNotSupported, DomainError, + CoercionFailed, UnificationFailed, + GeneratorsNeeded, PolynomialError, + MultivariatePolynomialError, + ExactQuotientFailed, + PolificationFailed, + ComputationFailed, + GeneratorsError, +) +from sympy.polys.polyutils import ( + basic_from_dict, + _sort_gens, + _unify_gens, + _dict_reorder, + _dict_from_expr, + _parallel_dict_from_expr, +) +from sympy.polys.rationaltools import together +from sympy.polys.rootisolation import dup_isolate_real_roots_list +from sympy.utilities import group, public, filldedent +from sympy.utilities.exceptions import sympy_deprecation_warning +from sympy.utilities.iterables import iterable, sift + + +# Required to avoid errors +import sympy.polys + +import mpmath +from mpmath.libmp.libhyper import NoConvergence + + + +def _polifyit(func): + @wraps(func) + def wrapper(f, g): + g = _sympify(g) + if isinstance(g, Poly): + return func(f, g) + elif isinstance(g, Expr): + try: + g = f.from_expr(g, *f.gens) + except PolynomialError: + if g.is_Matrix: + return NotImplemented + expr_method = getattr(f.as_expr(), func.__name__) + result = expr_method(g) + if result is not NotImplemented: + sympy_deprecation_warning( + """ + Mixing Poly with non-polynomial expressions in binary + operations is deprecated. Either explicitly convert + the non-Poly operand to a Poly with as_poly() or + convert the Poly to an Expr with as_expr(). + """, + deprecated_since_version="1.6", + active_deprecations_target="deprecated-poly-nonpoly-binary-operations", + ) + return result + else: + return func(f, g) + else: + return NotImplemented + return wrapper + + + +@public +class Poly(Basic): + """ + Generic class for representing and operating on polynomial expressions. + + See :ref:`polys-docs` for general documentation. + + Poly is a subclass of Basic rather than Expr but instances can be + converted to Expr with the :py:meth:`~.Poly.as_expr` method. + + .. deprecated:: 1.6 + + Combining Poly with non-Poly objects in binary operations is + deprecated. Explicitly convert both objects to either Poly or Expr + first. See :ref:`deprecated-poly-nonpoly-binary-operations`. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + Create a univariate polynomial: + + >>> Poly(x*(x**2 + x - 1)**2) + Poly(x**5 + 2*x**4 - x**3 - 2*x**2 + x, x, domain='ZZ') + + Create a univariate polynomial with specific domain: + + >>> from sympy import sqrt + >>> Poly(x**2 + 2*x + sqrt(3), domain='R') + Poly(1.0*x**2 + 2.0*x + 1.73205080756888, x, domain='RR') + + Create a multivariate polynomial: + + >>> Poly(y*x**2 + x*y + 1) + Poly(x**2*y + x*y + 1, x, y, domain='ZZ') + + Create a univariate polynomial, where y is a constant: + + >>> Poly(y*x**2 + x*y + 1,x) + Poly(y*x**2 + y*x + 1, x, domain='ZZ[y]') + + You can evaluate the above polynomial as a function of y: + + >>> Poly(y*x**2 + x*y + 1,x).eval(2) + 6*y + 1 + + See Also + ======== + + sympy.core.expr.Expr + + """ + + __slots__ = ('rep', 'gens') + + is_commutative = True + is_Poly = True + _op_priority = 10.001 + + def __new__(cls, rep, *gens, **args): + """Create a new polynomial instance out of something useful. """ + opt = options.build_options(gens, args) + + if 'order' in opt: + raise NotImplementedError("'order' keyword is not implemented yet") + + if isinstance(rep, (DMP, DMF, ANP, DomainElement)): + return cls._from_domain_element(rep, opt) + elif iterable(rep, exclude=str): + if isinstance(rep, dict): + return cls._from_dict(rep, opt) + else: + return cls._from_list(list(rep), opt) + else: + rep = sympify(rep) + + if rep.is_Poly: + return cls._from_poly(rep, opt) + else: + return cls._from_expr(rep, opt) + + # Poly does not pass its args to Basic.__new__ to be stored in _args so we + # have to emulate them here with an args property that derives from rep + # and gens which are instance attributes. This also means we need to + # define _hashable_content. The _hashable_content is rep and gens but args + # uses expr instead of rep (expr is the Basic version of rep). Passing + # expr in args means that Basic methods like subs should work. Using rep + # otherwise means that Poly can remain more efficient than Basic by + # avoiding creating a Basic instance just to be hashable. + + @classmethod + def new(cls, rep, *gens): + """Construct :class:`Poly` instance from raw representation. """ + if not isinstance(rep, DMP): + raise PolynomialError( + "invalid polynomial representation: %s" % rep) + elif rep.lev != len(gens) - 1: + raise PolynomialError("invalid arguments: %s, %s" % (rep, gens)) + + obj = Basic.__new__(cls) + obj.rep = rep + obj.gens = gens + + return obj + + @property + def expr(self): + return basic_from_dict(self.rep.to_sympy_dict(), *self.gens) + + @property + def args(self): + return (self.expr,) + self.gens + + def _hashable_content(self): + return (self.rep,) + self.gens + + @classmethod + def from_dict(cls, rep, *gens, **args): + """Construct a polynomial from a ``dict``. """ + opt = options.build_options(gens, args) + return cls._from_dict(rep, opt) + + @classmethod + def from_list(cls, rep, *gens, **args): + """Construct a polynomial from a ``list``. """ + opt = options.build_options(gens, args) + return cls._from_list(rep, opt) + + @classmethod + def from_poly(cls, rep, *gens, **args): + """Construct a polynomial from a polynomial. """ + opt = options.build_options(gens, args) + return cls._from_poly(rep, opt) + + @classmethod + def from_expr(cls, rep, *gens, **args): + """Construct a polynomial from an expression. """ + opt = options.build_options(gens, args) + return cls._from_expr(rep, opt) + + @classmethod + def _from_dict(cls, rep, opt): + """Construct a polynomial from a ``dict``. """ + gens = opt.gens + + if not gens: + raise GeneratorsNeeded( + "Cannot initialize from 'dict' without generators") + + level = len(gens) - 1 + domain = opt.domain + + if domain is None: + domain, rep = construct_domain(rep, opt=opt) + else: + for monom, coeff in rep.items(): + rep[monom] = domain.convert(coeff) + + return cls.new(DMP.from_dict(rep, level, domain), *gens) + + @classmethod + def _from_list(cls, rep, opt): + """Construct a polynomial from a ``list``. """ + gens = opt.gens + + if not gens: + raise GeneratorsNeeded( + "Cannot initialize from 'list' without generators") + elif len(gens) != 1: + raise MultivariatePolynomialError( + "'list' representation not supported") + + level = len(gens) - 1 + domain = opt.domain + + if domain is None: + domain, rep = construct_domain(rep, opt=opt) + else: + rep = list(map(domain.convert, rep)) + + return cls.new(DMP.from_list(rep, level, domain), *gens) + + @classmethod + def _from_poly(cls, rep, opt): + """Construct a polynomial from a polynomial. """ + if cls != rep.__class__: + rep = cls.new(rep.rep, *rep.gens) + + gens = opt.gens + field = opt.field + domain = opt.domain + + if gens and rep.gens != gens: + if set(rep.gens) != set(gens): + return cls._from_expr(rep.as_expr(), opt) + else: + rep = rep.reorder(*gens) + + if 'domain' in opt and domain: + rep = rep.set_domain(domain) + elif field is True: + rep = rep.to_field() + + return rep + + @classmethod + def _from_expr(cls, rep, opt): + """Construct a polynomial from an expression. """ + rep, opt = _dict_from_expr(rep, opt) + return cls._from_dict(rep, opt) + + @classmethod + def _from_domain_element(cls, rep, opt): + gens = opt.gens + domain = opt.domain + + level = len(gens) - 1 + rep = [domain.convert(rep)] + + return cls.new(DMP.from_list(rep, level, domain), *gens) + + def __hash__(self): + return super().__hash__() + + @property + def free_symbols(self): + """ + Free symbols of a polynomial expression. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> Poly(x**2 + 1).free_symbols + {x} + >>> Poly(x**2 + y).free_symbols + {x, y} + >>> Poly(x**2 + y, x).free_symbols + {x, y} + >>> Poly(x**2 + y, x, z).free_symbols + {x, y} + + """ + symbols = set() + gens = self.gens + for i in range(len(gens)): + for monom in self.monoms(): + if monom[i]: + symbols |= gens[i].free_symbols + break + + return symbols | self.free_symbols_in_domain + + @property + def free_symbols_in_domain(self): + """ + Free symbols of the domain of ``self``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 1).free_symbols_in_domain + set() + >>> Poly(x**2 + y).free_symbols_in_domain + set() + >>> Poly(x**2 + y, x).free_symbols_in_domain + {y} + + """ + domain, symbols = self.rep.dom, set() + + if domain.is_Composite: + for gen in domain.symbols: + symbols |= gen.free_symbols + elif domain.is_EX: + for coeff in self.coeffs(): + symbols |= coeff.free_symbols + + return symbols + + @property + def gen(self): + """ + Return the principal generator. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).gen + x + + """ + return self.gens[0] + + @property + def domain(self): + """Get the ground domain of a :py:class:`~.Poly` + + Returns + ======= + + :py:class:`~.Domain`: + Ground domain of the :py:class:`~.Poly`. + + Examples + ======== + + >>> from sympy import Poly, Symbol + >>> x = Symbol('x') + >>> p = Poly(x**2 + x) + >>> p + Poly(x**2 + x, x, domain='ZZ') + >>> p.domain + ZZ + """ + return self.get_domain() + + @property + def zero(self): + """Return zero polynomial with ``self``'s properties. """ + return self.new(self.rep.zero(self.rep.lev, self.rep.dom), *self.gens) + + @property + def one(self): + """Return one polynomial with ``self``'s properties. """ + return self.new(self.rep.one(self.rep.lev, self.rep.dom), *self.gens) + + @property + def unit(self): + """Return unit polynomial with ``self``'s properties. """ + return self.new(self.rep.unit(self.rep.lev, self.rep.dom), *self.gens) + + def unify(f, g): + """ + Make ``f`` and ``g`` belong to the same domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f, g = Poly(x/2 + 1), Poly(2*x + 1) + + >>> f + Poly(1/2*x + 1, x, domain='QQ') + >>> g + Poly(2*x + 1, x, domain='ZZ') + + >>> F, G = f.unify(g) + + >>> F + Poly(1/2*x + 1, x, domain='QQ') + >>> G + Poly(2*x + 1, x, domain='QQ') + + """ + _, per, F, G = f._unify(g) + return per(F), per(G) + + def _unify(f, g): + g = sympify(g) + + if not g.is_Poly: + try: + return f.rep.dom, f.per, f.rep, f.rep.per(f.rep.dom.from_sympy(g)) + except CoercionFailed: + raise UnificationFailed("Cannot unify %s with %s" % (f, g)) + + if isinstance(f.rep, DMP) and isinstance(g.rep, DMP): + gens = _unify_gens(f.gens, g.gens) + + dom, lev = f.rep.dom.unify(g.rep.dom, gens), len(gens) - 1 + + if f.gens != gens: + f_monoms, f_coeffs = _dict_reorder( + f.rep.to_dict(), f.gens, gens) + + if f.rep.dom != dom: + f_coeffs = [dom.convert(c, f.rep.dom) for c in f_coeffs] + + F = DMP(dict(list(zip(f_monoms, f_coeffs))), dom, lev) + else: + F = f.rep.convert(dom) + + if g.gens != gens: + g_monoms, g_coeffs = _dict_reorder( + g.rep.to_dict(), g.gens, gens) + + if g.rep.dom != dom: + g_coeffs = [dom.convert(c, g.rep.dom) for c in g_coeffs] + + G = DMP(dict(list(zip(g_monoms, g_coeffs))), dom, lev) + else: + G = g.rep.convert(dom) + else: + raise UnificationFailed("Cannot unify %s with %s" % (f, g)) + + cls = f.__class__ + + def per(rep, dom=dom, gens=gens, remove=None): + if remove is not None: + gens = gens[:remove] + gens[remove + 1:] + + if not gens: + return dom.to_sympy(rep) + + return cls.new(rep, *gens) + + return dom, per, F, G + + def per(f, rep, gens=None, remove=None): + """ + Create a Poly out of the given representation. + + Examples + ======== + + >>> from sympy import Poly, ZZ + >>> from sympy.abc import x, y + + >>> from sympy.polys.polyclasses import DMP + + >>> a = Poly(x**2 + 1) + + >>> a.per(DMP([ZZ(1), ZZ(1)], ZZ), gens=[y]) + Poly(y + 1, y, domain='ZZ') + + """ + if gens is None: + gens = f.gens + + if remove is not None: + gens = gens[:remove] + gens[remove + 1:] + + if not gens: + return f.rep.dom.to_sympy(rep) + + return f.__class__.new(rep, *gens) + + def set_domain(f, domain): + """Set the ground domain of ``f``. """ + opt = options.build_options(f.gens, {'domain': domain}) + return f.per(f.rep.convert(opt.domain)) + + def get_domain(f): + """Get the ground domain of ``f``. """ + return f.rep.dom + + def set_modulus(f, modulus): + """ + Set the modulus of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(5*x**2 + 2*x - 1, x).set_modulus(2) + Poly(x**2 + 1, x, modulus=2) + + """ + modulus = options.Modulus.preprocess(modulus) + return f.set_domain(FF(modulus)) + + def get_modulus(f): + """ + Get the modulus of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, modulus=2).get_modulus() + 2 + + """ + domain = f.get_domain() + + if domain.is_FiniteField: + return Integer(domain.characteristic()) + else: + raise PolynomialError("not a polynomial over a Galois field") + + def _eval_subs(f, old, new): + """Internal implementation of :func:`subs`. """ + if old in f.gens: + if new.is_number: + return f.eval(old, new) + else: + try: + return f.replace(old, new) + except PolynomialError: + pass + + return f.as_expr().subs(old, new) + + def exclude(f): + """ + Remove unnecessary generators from ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import a, b, c, d, x + + >>> Poly(a + x, a, b, c, d, x).exclude() + Poly(a + x, a, x, domain='ZZ') + + """ + J, new = f.rep.exclude() + gens = [gen for j, gen in enumerate(f.gens) if j not in J] + + return f.per(new, gens=gens) + + def replace(f, x, y=None, **_ignore): + # XXX this does not match Basic's signature + """ + Replace ``x`` with ``y`` in generators list. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 1, x).replace(x, y) + Poly(y**2 + 1, y, domain='ZZ') + + """ + if y is None: + if f.is_univariate: + x, y = f.gen, x + else: + raise PolynomialError( + "syntax supported only in univariate case") + + if x == y or x not in f.gens: + return f + + if x in f.gens and y not in f.gens: + dom = f.get_domain() + + if not dom.is_Composite or y not in dom.symbols: + gens = list(f.gens) + gens[gens.index(x)] = y + return f.per(f.rep, gens=gens) + + raise PolynomialError("Cannot replace %s with %s in %s" % (x, y, f)) + + def match(f, *args, **kwargs): + """Match expression from Poly. See Basic.match()""" + return f.as_expr().match(*args, **kwargs) + + def reorder(f, *gens, **args): + """ + Efficiently apply new order of generators. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + x*y**2, x, y).reorder(y, x) + Poly(y**2*x + x**2, y, x, domain='ZZ') + + """ + opt = options.Options((), args) + + if not gens: + gens = _sort_gens(f.gens, opt=opt) + elif set(f.gens) != set(gens): + raise PolynomialError( + "generators list can differ only up to order of elements") + + rep = dict(list(zip(*_dict_reorder(f.rep.to_dict(), f.gens, gens)))) + + return f.per(DMP(rep, f.rep.dom, len(gens) - 1), gens=gens) + + def ltrim(f, gen): + """ + Remove dummy generators from ``f`` that are to the left of + specified ``gen`` in the generators as ordered. When ``gen`` + is an integer, it refers to the generator located at that + position within the tuple of generators of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> Poly(y**2 + y*z**2, x, y, z).ltrim(y) + Poly(y**2 + y*z**2, y, z, domain='ZZ') + >>> Poly(z, x, y, z).ltrim(-1) + Poly(z, z, domain='ZZ') + + """ + rep = f.as_dict(native=True) + j = f._gen_to_level(gen) + + terms = {} + + for monom, coeff in rep.items(): + + if any(monom[:j]): + # some generator is used in the portion to be trimmed + raise PolynomialError("Cannot left trim %s" % f) + + terms[monom[j:]] = coeff + + gens = f.gens[j:] + + return f.new(DMP.from_dict(terms, len(gens) - 1, f.rep.dom), *gens) + + def has_only_gens(f, *gens): + """ + Return ``True`` if ``Poly(f, *gens)`` retains ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> Poly(x*y + 1, x, y, z).has_only_gens(x, y) + True + >>> Poly(x*y + z, x, y, z).has_only_gens(x, y) + False + + """ + indices = set() + + for gen in gens: + try: + index = f.gens.index(gen) + except ValueError: + raise GeneratorsError( + "%s doesn't have %s as generator" % (f, gen)) + else: + indices.add(index) + + for monom in f.monoms(): + for i, elt in enumerate(monom): + if i not in indices and elt: + return False + + return True + + def to_ring(f): + """ + Make the ground domain a ring. + + Examples + ======== + + >>> from sympy import Poly, QQ + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, domain=QQ).to_ring() + Poly(x**2 + 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'to_ring'): + result = f.rep.to_ring() + else: # pragma: no cover + raise OperationNotSupported(f, 'to_ring') + + return f.per(result) + + def to_field(f): + """ + Make the ground domain a field. + + Examples + ======== + + >>> from sympy import Poly, ZZ + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x, domain=ZZ).to_field() + Poly(x**2 + 1, x, domain='QQ') + + """ + if hasattr(f.rep, 'to_field'): + result = f.rep.to_field() + else: # pragma: no cover + raise OperationNotSupported(f, 'to_field') + + return f.per(result) + + def to_exact(f): + """ + Make the ground domain exact. + + Examples + ======== + + >>> from sympy import Poly, RR + >>> from sympy.abc import x + + >>> Poly(x**2 + 1.0, x, domain=RR).to_exact() + Poly(x**2 + 1, x, domain='QQ') + + """ + if hasattr(f.rep, 'to_exact'): + result = f.rep.to_exact() + else: # pragma: no cover + raise OperationNotSupported(f, 'to_exact') + + return f.per(result) + + def retract(f, field=None): + """ + Recalculate the ground domain of a polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = Poly(x**2 + 1, x, domain='QQ[y]') + >>> f + Poly(x**2 + 1, x, domain='QQ[y]') + + >>> f.retract() + Poly(x**2 + 1, x, domain='ZZ') + >>> f.retract(field=True) + Poly(x**2 + 1, x, domain='QQ') + + """ + dom, rep = construct_domain(f.as_dict(zero=True), + field=field, composite=f.domain.is_Composite or None) + return f.from_dict(rep, f.gens, domain=dom) + + def slice(f, x, m, n=None): + """Take a continuous subsequence of terms of ``f``. """ + if n is None: + j, m, n = 0, x, m + else: + j = f._gen_to_level(x) + + m, n = int(m), int(n) + + if hasattr(f.rep, 'slice'): + result = f.rep.slice(m, n, j) + else: # pragma: no cover + raise OperationNotSupported(f, 'slice') + + return f.per(result) + + def coeffs(f, order=None): + """ + Returns all non-zero coefficients from ``f`` in lex order. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x + 3, x).coeffs() + [1, 2, 3] + + See Also + ======== + all_coeffs + coeff_monomial + nth + + """ + return [f.rep.dom.to_sympy(c) for c in f.rep.coeffs(order=order)] + + def monoms(f, order=None): + """ + Returns all non-zero monomials from ``f`` in lex order. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 2*x*y**2 + x*y + 3*y, x, y).monoms() + [(2, 0), (1, 2), (1, 1), (0, 1)] + + See Also + ======== + all_monoms + + """ + return f.rep.monoms(order=order) + + def terms(f, order=None): + """ + Returns all non-zero terms from ``f`` in lex order. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 2*x*y**2 + x*y + 3*y, x, y).terms() + [((2, 0), 1), ((1, 2), 2), ((1, 1), 1), ((0, 1), 3)] + + See Also + ======== + all_terms + + """ + return [(m, f.rep.dom.to_sympy(c)) for m, c in f.rep.terms(order=order)] + + def all_coeffs(f): + """ + Returns all coefficients from a univariate polynomial ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x - 1, x).all_coeffs() + [1, 0, 2, -1] + + """ + return [f.rep.dom.to_sympy(c) for c in f.rep.all_coeffs()] + + def all_monoms(f): + """ + Returns all monomials from a univariate polynomial ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x - 1, x).all_monoms() + [(3,), (2,), (1,), (0,)] + + See Also + ======== + all_terms + + """ + return f.rep.all_monoms() + + def all_terms(f): + """ + Returns all terms from a univariate polynomial ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x - 1, x).all_terms() + [((3,), 1), ((2,), 0), ((1,), 2), ((0,), -1)] + + """ + return [(m, f.rep.dom.to_sympy(c)) for m, c in f.rep.all_terms()] + + def termwise(f, func, *gens, **args): + """ + Apply a function to all terms of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> def func(k, coeff): + ... k = k[0] + ... return coeff//10**(2-k) + + >>> Poly(x**2 + 20*x + 400).termwise(func) + Poly(x**2 + 2*x + 4, x, domain='ZZ') + + """ + terms = {} + + for monom, coeff in f.terms(): + result = func(monom, coeff) + + if isinstance(result, tuple): + monom, coeff = result + else: + coeff = result + + if coeff: + if monom not in terms: + terms[monom] = coeff + else: + raise PolynomialError( + "%s monomial was generated twice" % monom) + + return f.from_dict(terms, *(gens or f.gens), **args) + + def length(f): + """ + Returns the number of non-zero terms in ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 2*x - 1).length() + 3 + + """ + return len(f.as_dict()) + + def as_dict(f, native=False, zero=False): + """ + Switch to a ``dict`` representation. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 2*x*y**2 - y, x, y).as_dict() + {(0, 1): -1, (1, 2): 2, (2, 0): 1} + + """ + if native: + return f.rep.to_dict(zero=zero) + else: + return f.rep.to_sympy_dict(zero=zero) + + def as_list(f, native=False): + """Switch to a ``list`` representation. """ + if native: + return f.rep.to_list() + else: + return f.rep.to_sympy_list() + + def as_expr(f, *gens): + """ + Convert a Poly instance to an Expr instance. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = Poly(x**2 + 2*x*y**2 - y, x, y) + + >>> f.as_expr() + x**2 + 2*x*y**2 - y + >>> f.as_expr({x: 5}) + 10*y**2 - y + 25 + >>> f.as_expr(5, 6) + 379 + + """ + if not gens: + return f.expr + + if len(gens) == 1 and isinstance(gens[0], dict): + mapping = gens[0] + gens = list(f.gens) + + for gen, value in mapping.items(): + try: + index = gens.index(gen) + except ValueError: + raise GeneratorsError( + "%s doesn't have %s as generator" % (f, gen)) + else: + gens[index] = value + + return basic_from_dict(f.rep.to_sympy_dict(), *gens) + + def as_poly(self, *gens, **args): + """Converts ``self`` to a polynomial or returns ``None``. + + >>> from sympy import sin + >>> from sympy.abc import x, y + + >>> print((x**2 + x*y).as_poly()) + Poly(x**2 + x*y, x, y, domain='ZZ') + + >>> print((x**2 + x*y).as_poly(x, y)) + Poly(x**2 + x*y, x, y, domain='ZZ') + + >>> print((x**2 + sin(y)).as_poly(x, y)) + None + + """ + try: + poly = Poly(self, *gens, **args) + + if not poly.is_Poly: + return None + else: + return poly + except PolynomialError: + return None + + def lift(f): + """ + Convert algebraic coefficients to rationals. + + Examples + ======== + + >>> from sympy import Poly, I + >>> from sympy.abc import x + + >>> Poly(x**2 + I*x + 1, x, extension=I).lift() + Poly(x**4 + 3*x**2 + 1, x, domain='QQ') + + """ + if hasattr(f.rep, 'lift'): + result = f.rep.lift() + else: # pragma: no cover + raise OperationNotSupported(f, 'lift') + + return f.per(result) + + def deflate(f): + """ + Reduce degree of ``f`` by mapping ``x_i**m`` to ``y_i``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**6*y**2 + x**3 + 1, x, y).deflate() + ((3, 2), Poly(x**2*y + x + 1, x, y, domain='ZZ')) + + """ + if hasattr(f.rep, 'deflate'): + J, result = f.rep.deflate() + else: # pragma: no cover + raise OperationNotSupported(f, 'deflate') + + return J, f.per(result) + + def inject(f, front=False): + """ + Inject ground domain generators into ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = Poly(x**2*y + x*y**3 + x*y + 1, x) + + >>> f.inject() + Poly(x**2*y + x*y**3 + x*y + 1, x, y, domain='ZZ') + >>> f.inject(front=True) + Poly(y**3*x + y*x**2 + y*x + 1, y, x, domain='ZZ') + + """ + dom = f.rep.dom + + if dom.is_Numerical: + return f + elif not dom.is_Poly: + raise DomainError("Cannot inject generators over %s" % dom) + + if hasattr(f.rep, 'inject'): + result = f.rep.inject(front=front) + else: # pragma: no cover + raise OperationNotSupported(f, 'inject') + + if front: + gens = dom.symbols + f.gens + else: + gens = f.gens + dom.symbols + + return f.new(result, *gens) + + def eject(f, *gens): + """ + Eject selected generators into the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = Poly(x**2*y + x*y**3 + x*y + 1, x, y) + + >>> f.eject(x) + Poly(x*y**3 + (x**2 + x)*y + 1, y, domain='ZZ[x]') + >>> f.eject(y) + Poly(y*x**2 + (y**3 + y)*x + 1, x, domain='ZZ[y]') + + """ + dom = f.rep.dom + + if not dom.is_Numerical: + raise DomainError("Cannot eject generators over %s" % dom) + + k = len(gens) + + if f.gens[:k] == gens: + _gens, front = f.gens[k:], True + elif f.gens[-k:] == gens: + _gens, front = f.gens[:-k], False + else: + raise NotImplementedError( + "can only eject front or back generators") + + dom = dom.inject(*gens) + + if hasattr(f.rep, 'eject'): + result = f.rep.eject(dom, front=front) + else: # pragma: no cover + raise OperationNotSupported(f, 'eject') + + return f.new(result, *_gens) + + def terms_gcd(f): + """ + Remove GCD of terms from the polynomial ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**6*y**2 + x**3*y, x, y).terms_gcd() + ((3, 1), Poly(x**3*y + 1, x, y, domain='ZZ')) + + """ + if hasattr(f.rep, 'terms_gcd'): + J, result = f.rep.terms_gcd() + else: # pragma: no cover + raise OperationNotSupported(f, 'terms_gcd') + + return J, f.per(result) + + def add_ground(f, coeff): + """ + Add an element of the ground domain to ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x + 1).add_ground(2) + Poly(x + 3, x, domain='ZZ') + + """ + if hasattr(f.rep, 'add_ground'): + result = f.rep.add_ground(coeff) + else: # pragma: no cover + raise OperationNotSupported(f, 'add_ground') + + return f.per(result) + + def sub_ground(f, coeff): + """ + Subtract an element of the ground domain from ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x + 1).sub_ground(2) + Poly(x - 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'sub_ground'): + result = f.rep.sub_ground(coeff) + else: # pragma: no cover + raise OperationNotSupported(f, 'sub_ground') + + return f.per(result) + + def mul_ground(f, coeff): + """ + Multiply ``f`` by a an element of the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x + 1).mul_ground(2) + Poly(2*x + 2, x, domain='ZZ') + + """ + if hasattr(f.rep, 'mul_ground'): + result = f.rep.mul_ground(coeff) + else: # pragma: no cover + raise OperationNotSupported(f, 'mul_ground') + + return f.per(result) + + def quo_ground(f, coeff): + """ + Quotient of ``f`` by a an element of the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x + 4).quo_ground(2) + Poly(x + 2, x, domain='ZZ') + + >>> Poly(2*x + 3).quo_ground(2) + Poly(x + 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'quo_ground'): + result = f.rep.quo_ground(coeff) + else: # pragma: no cover + raise OperationNotSupported(f, 'quo_ground') + + return f.per(result) + + def exquo_ground(f, coeff): + """ + Exact quotient of ``f`` by a an element of the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x + 4).exquo_ground(2) + Poly(x + 2, x, domain='ZZ') + + >>> Poly(2*x + 3).exquo_ground(2) + Traceback (most recent call last): + ... + ExactQuotientFailed: 2 does not divide 3 in ZZ + + """ + if hasattr(f.rep, 'exquo_ground'): + result = f.rep.exquo_ground(coeff) + else: # pragma: no cover + raise OperationNotSupported(f, 'exquo_ground') + + return f.per(result) + + def abs(f): + """ + Make all coefficients in ``f`` positive. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).abs() + Poly(x**2 + 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'abs'): + result = f.rep.abs() + else: # pragma: no cover + raise OperationNotSupported(f, 'abs') + + return f.per(result) + + def neg(f): + """ + Negate all coefficients in ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).neg() + Poly(-x**2 + 1, x, domain='ZZ') + + >>> -Poly(x**2 - 1, x) + Poly(-x**2 + 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'neg'): + result = f.rep.neg() + else: # pragma: no cover + raise OperationNotSupported(f, 'neg') + + return f.per(result) + + def add(f, g): + """ + Add two polynomials ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).add(Poly(x - 2, x)) + Poly(x**2 + x - 1, x, domain='ZZ') + + >>> Poly(x**2 + 1, x) + Poly(x - 2, x) + Poly(x**2 + x - 1, x, domain='ZZ') + + """ + g = sympify(g) + + if not g.is_Poly: + return f.add_ground(g) + + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'add'): + result = F.add(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'add') + + return per(result) + + def sub(f, g): + """ + Subtract two polynomials ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).sub(Poly(x - 2, x)) + Poly(x**2 - x + 3, x, domain='ZZ') + + >>> Poly(x**2 + 1, x) - Poly(x - 2, x) + Poly(x**2 - x + 3, x, domain='ZZ') + + """ + g = sympify(g) + + if not g.is_Poly: + return f.sub_ground(g) + + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'sub'): + result = F.sub(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'sub') + + return per(result) + + def mul(f, g): + """ + Multiply two polynomials ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).mul(Poly(x - 2, x)) + Poly(x**3 - 2*x**2 + x - 2, x, domain='ZZ') + + >>> Poly(x**2 + 1, x)*Poly(x - 2, x) + Poly(x**3 - 2*x**2 + x - 2, x, domain='ZZ') + + """ + g = sympify(g) + + if not g.is_Poly: + return f.mul_ground(g) + + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'mul'): + result = F.mul(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'mul') + + return per(result) + + def sqr(f): + """ + Square a polynomial ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x - 2, x).sqr() + Poly(x**2 - 4*x + 4, x, domain='ZZ') + + >>> Poly(x - 2, x)**2 + Poly(x**2 - 4*x + 4, x, domain='ZZ') + + """ + if hasattr(f.rep, 'sqr'): + result = f.rep.sqr() + else: # pragma: no cover + raise OperationNotSupported(f, 'sqr') + + return f.per(result) + + def pow(f, n): + """ + Raise ``f`` to a non-negative power ``n``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x - 2, x).pow(3) + Poly(x**3 - 6*x**2 + 12*x - 8, x, domain='ZZ') + + >>> Poly(x - 2, x)**3 + Poly(x**3 - 6*x**2 + 12*x - 8, x, domain='ZZ') + + """ + n = int(n) + + if hasattr(f.rep, 'pow'): + result = f.rep.pow(n) + else: # pragma: no cover + raise OperationNotSupported(f, 'pow') + + return f.per(result) + + def pdiv(f, g): + """ + Polynomial pseudo-division of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).pdiv(Poly(2*x - 4, x)) + (Poly(2*x + 4, x, domain='ZZ'), Poly(20, x, domain='ZZ')) + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'pdiv'): + q, r = F.pdiv(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'pdiv') + + return per(q), per(r) + + def prem(f, g): + """ + Polynomial pseudo-remainder of ``f`` by ``g``. + + Caveat: The function prem(f, g, x) can be safely used to compute + in Z[x] _only_ subresultant polynomial remainder sequences (prs's). + + To safely compute Euclidean and Sturmian prs's in Z[x] + employ anyone of the corresponding functions found in + the module sympy.polys.subresultants_qq_zz. The functions + in the module with suffix _pg compute prs's in Z[x] employing + rem(f, g, x), whereas the functions with suffix _amv + compute prs's in Z[x] employing rem_z(f, g, x). + + The function rem_z(f, g, x) differs from prem(f, g, x) in that + to compute the remainder polynomials in Z[x] it premultiplies + the divident times the absolute value of the leading coefficient + of the divisor raised to the power degree(f, x) - degree(g, x) + 1. + + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).prem(Poly(2*x - 4, x)) + Poly(20, x, domain='ZZ') + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'prem'): + result = F.prem(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'prem') + + return per(result) + + def pquo(f, g): + """ + Polynomial pseudo-quotient of ``f`` by ``g``. + + See the Caveat note in the function prem(f, g). + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).pquo(Poly(2*x - 4, x)) + Poly(2*x + 4, x, domain='ZZ') + + >>> Poly(x**2 - 1, x).pquo(Poly(2*x - 2, x)) + Poly(2*x + 2, x, domain='ZZ') + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'pquo'): + result = F.pquo(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'pquo') + + return per(result) + + def pexquo(f, g): + """ + Polynomial exact pseudo-quotient of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).pexquo(Poly(2*x - 2, x)) + Poly(2*x + 2, x, domain='ZZ') + + >>> Poly(x**2 + 1, x).pexquo(Poly(2*x - 4, x)) + Traceback (most recent call last): + ... + ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1 + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'pexquo'): + try: + result = F.pexquo(G) + except ExactQuotientFailed as exc: + raise exc.new(f.as_expr(), g.as_expr()) + else: # pragma: no cover + raise OperationNotSupported(f, 'pexquo') + + return per(result) + + def div(f, g, auto=True): + """ + Polynomial division with remainder of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).div(Poly(2*x - 4, x)) + (Poly(1/2*x + 1, x, domain='QQ'), Poly(5, x, domain='QQ')) + + >>> Poly(x**2 + 1, x).div(Poly(2*x - 4, x), auto=False) + (Poly(0, x, domain='ZZ'), Poly(x**2 + 1, x, domain='ZZ')) + + """ + dom, per, F, G = f._unify(g) + retract = False + + if auto and dom.is_Ring and not dom.is_Field: + F, G = F.to_field(), G.to_field() + retract = True + + if hasattr(f.rep, 'div'): + q, r = F.div(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'div') + + if retract: + try: + Q, R = q.to_ring(), r.to_ring() + except CoercionFailed: + pass + else: + q, r = Q, R + + return per(q), per(r) + + def rem(f, g, auto=True): + """ + Computes the polynomial remainder of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).rem(Poly(2*x - 4, x)) + Poly(5, x, domain='ZZ') + + >>> Poly(x**2 + 1, x).rem(Poly(2*x - 4, x), auto=False) + Poly(x**2 + 1, x, domain='ZZ') + + """ + dom, per, F, G = f._unify(g) + retract = False + + if auto and dom.is_Ring and not dom.is_Field: + F, G = F.to_field(), G.to_field() + retract = True + + if hasattr(f.rep, 'rem'): + r = F.rem(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'rem') + + if retract: + try: + r = r.to_ring() + except CoercionFailed: + pass + + return per(r) + + def quo(f, g, auto=True): + """ + Computes polynomial quotient of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).quo(Poly(2*x - 4, x)) + Poly(1/2*x + 1, x, domain='QQ') + + >>> Poly(x**2 - 1, x).quo(Poly(x - 1, x)) + Poly(x + 1, x, domain='ZZ') + + """ + dom, per, F, G = f._unify(g) + retract = False + + if auto and dom.is_Ring and not dom.is_Field: + F, G = F.to_field(), G.to_field() + retract = True + + if hasattr(f.rep, 'quo'): + q = F.quo(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'quo') + + if retract: + try: + q = q.to_ring() + except CoercionFailed: + pass + + return per(q) + + def exquo(f, g, auto=True): + """ + Computes polynomial exact quotient of ``f`` by ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).exquo(Poly(x - 1, x)) + Poly(x + 1, x, domain='ZZ') + + >>> Poly(x**2 + 1, x).exquo(Poly(2*x - 4, x)) + Traceback (most recent call last): + ... + ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1 + + """ + dom, per, F, G = f._unify(g) + retract = False + + if auto and dom.is_Ring and not dom.is_Field: + F, G = F.to_field(), G.to_field() + retract = True + + if hasattr(f.rep, 'exquo'): + try: + q = F.exquo(G) + except ExactQuotientFailed as exc: + raise exc.new(f.as_expr(), g.as_expr()) + else: # pragma: no cover + raise OperationNotSupported(f, 'exquo') + + if retract: + try: + q = q.to_ring() + except CoercionFailed: + pass + + return per(q) + + def _gen_to_level(f, gen): + """Returns level associated with the given generator. """ + if isinstance(gen, int): + length = len(f.gens) + + if -length <= gen < length: + if gen < 0: + return length + gen + else: + return gen + else: + raise PolynomialError("-%s <= gen < %s expected, got %s" % + (length, length, gen)) + else: + try: + return f.gens.index(sympify(gen)) + except ValueError: + raise PolynomialError( + "a valid generator expected, got %s" % gen) + + def degree(f, gen=0): + """ + Returns degree of ``f`` in ``x_j``. + + The degree of 0 is negative infinity. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + y*x + 1, x, y).degree() + 2 + >>> Poly(x**2 + y*x + y, x, y).degree(y) + 1 + >>> Poly(0, x).degree() + -oo + + """ + j = f._gen_to_level(gen) + + if hasattr(f.rep, 'degree'): + return f.rep.degree(j) + else: # pragma: no cover + raise OperationNotSupported(f, 'degree') + + def degree_list(f): + """ + Returns a list of degrees of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + y*x + 1, x, y).degree_list() + (2, 1) + + """ + if hasattr(f.rep, 'degree_list'): + return f.rep.degree_list() + else: # pragma: no cover + raise OperationNotSupported(f, 'degree_list') + + def total_degree(f): + """ + Returns the total degree of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + y*x + 1, x, y).total_degree() + 2 + >>> Poly(x + y**5, x, y).total_degree() + 5 + + """ + if hasattr(f.rep, 'total_degree'): + return f.rep.total_degree() + else: # pragma: no cover + raise OperationNotSupported(f, 'total_degree') + + def homogenize(f, s): + """ + Returns the homogeneous polynomial of ``f``. + + A homogeneous polynomial is a polynomial whose all monomials with + non-zero coefficients have the same total degree. If you only + want to check if a polynomial is homogeneous, then use + :func:`Poly.is_homogeneous`. If you want not only to check if a + polynomial is homogeneous but also compute its homogeneous order, + then use :func:`Poly.homogeneous_order`. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> f = Poly(x**5 + 2*x**2*y**2 + 9*x*y**3) + >>> f.homogenize(z) + Poly(x**5 + 2*x**2*y**2*z + 9*x*y**3*z, x, y, z, domain='ZZ') + + """ + if not isinstance(s, Symbol): + raise TypeError("``Symbol`` expected, got %s" % type(s)) + if s in f.gens: + i = f.gens.index(s) + gens = f.gens + else: + i = len(f.gens) + gens = f.gens + (s,) + if hasattr(f.rep, 'homogenize'): + return f.per(f.rep.homogenize(i), gens=gens) + raise OperationNotSupported(f, 'homogeneous_order') + + def homogeneous_order(f): + """ + Returns the homogeneous order of ``f``. + + A homogeneous polynomial is a polynomial whose all monomials with + non-zero coefficients have the same total degree. This degree is + the homogeneous order of ``f``. If you only want to check if a + polynomial is homogeneous, then use :func:`Poly.is_homogeneous`. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = Poly(x**5 + 2*x**3*y**2 + 9*x*y**4) + >>> f.homogeneous_order() + 5 + + """ + if hasattr(f.rep, 'homogeneous_order'): + return f.rep.homogeneous_order() + else: # pragma: no cover + raise OperationNotSupported(f, 'homogeneous_order') + + def LC(f, order=None): + """ + Returns the leading coefficient of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(4*x**3 + 2*x**2 + 3*x, x).LC() + 4 + + """ + if order is not None: + return f.coeffs(order)[0] + + if hasattr(f.rep, 'LC'): + result = f.rep.LC() + else: # pragma: no cover + raise OperationNotSupported(f, 'LC') + + return f.rep.dom.to_sympy(result) + + def TC(f): + """ + Returns the trailing coefficient of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x**2 + 3*x, x).TC() + 0 + + """ + if hasattr(f.rep, 'TC'): + result = f.rep.TC() + else: # pragma: no cover + raise OperationNotSupported(f, 'TC') + + return f.rep.dom.to_sympy(result) + + def EC(f, order=None): + """ + Returns the last non-zero coefficient of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 + 2*x**2 + 3*x, x).EC() + 3 + + """ + if hasattr(f.rep, 'coeffs'): + return f.coeffs(order)[-1] + else: # pragma: no cover + raise OperationNotSupported(f, 'EC') + + def coeff_monomial(f, monom): + """ + Returns the coefficient of ``monom`` in ``f`` if there, else None. + + Examples + ======== + + >>> from sympy import Poly, exp + >>> from sympy.abc import x, y + + >>> p = Poly(24*x*y*exp(8) + 23*x, x, y) + + >>> p.coeff_monomial(x) + 23 + >>> p.coeff_monomial(y) + 0 + >>> p.coeff_monomial(x*y) + 24*exp(8) + + Note that ``Expr.coeff()`` behaves differently, collecting terms + if possible; the Poly must be converted to an Expr to use that + method, however: + + >>> p.as_expr().coeff(x) + 24*y*exp(8) + 23 + >>> p.as_expr().coeff(y) + 24*x*exp(8) + >>> p.as_expr().coeff(x*y) + 24*exp(8) + + See Also + ======== + nth: more efficient query using exponents of the monomial's generators + + """ + return f.nth(*Monomial(monom, f.gens).exponents) + + def nth(f, *N): + """ + Returns the ``n``-th coefficient of ``f`` where ``N`` are the + exponents of the generators in the term of interest. + + Examples + ======== + + >>> from sympy import Poly, sqrt + >>> from sympy.abc import x, y + + >>> Poly(x**3 + 2*x**2 + 3*x, x).nth(2) + 2 + >>> Poly(x**3 + 2*x*y**2 + y**2, x, y).nth(1, 2) + 2 + >>> Poly(4*sqrt(x)*y) + Poly(4*y*(sqrt(x)), y, sqrt(x), domain='ZZ') + >>> _.nth(1, 1) + 4 + + See Also + ======== + coeff_monomial + + """ + if hasattr(f.rep, 'nth'): + if len(N) != len(f.gens): + raise ValueError('exponent of each generator must be specified') + result = f.rep.nth(*list(map(int, N))) + else: # pragma: no cover + raise OperationNotSupported(f, 'nth') + + return f.rep.dom.to_sympy(result) + + def coeff(f, x, n=1, right=False): + # the semantics of coeff_monomial and Expr.coeff are different; + # if someone is working with a Poly, they should be aware of the + # differences and chose the method best suited for the query. + # Alternatively, a pure-polys method could be written here but + # at this time the ``right`` keyword would be ignored because Poly + # doesn't work with non-commutatives. + raise NotImplementedError( + 'Either convert to Expr with `as_expr` method ' + 'to use Expr\'s coeff method or else use the ' + '`coeff_monomial` method of Polys.') + + def LM(f, order=None): + """ + Returns the leading monomial of ``f``. + + The Leading monomial signifies the monomial having + the highest power of the principal generator in the + expression f. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).LM() + x**2*y**0 + + """ + return Monomial(f.monoms(order)[0], f.gens) + + def EM(f, order=None): + """ + Returns the last non-zero monomial of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).EM() + x**0*y**1 + + """ + return Monomial(f.monoms(order)[-1], f.gens) + + def LT(f, order=None): + """ + Returns the leading term of ``f``. + + The Leading term signifies the term having + the highest power of the principal generator in the + expression f along with its coefficient. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).LT() + (x**2*y**0, 4) + + """ + monom, coeff = f.terms(order)[0] + return Monomial(monom, f.gens), coeff + + def ET(f, order=None): + """ + Returns the last non-zero term of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(4*x**2 + 2*x*y**2 + x*y + 3*y, x, y).ET() + (x**0*y**1, 3) + + """ + monom, coeff = f.terms(order)[-1] + return Monomial(monom, f.gens), coeff + + def max_norm(f): + """ + Returns maximum norm of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(-x**2 + 2*x - 3, x).max_norm() + 3 + + """ + if hasattr(f.rep, 'max_norm'): + result = f.rep.max_norm() + else: # pragma: no cover + raise OperationNotSupported(f, 'max_norm') + + return f.rep.dom.to_sympy(result) + + def l1_norm(f): + """ + Returns l1 norm of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(-x**2 + 2*x - 3, x).l1_norm() + 6 + + """ + if hasattr(f.rep, 'l1_norm'): + result = f.rep.l1_norm() + else: # pragma: no cover + raise OperationNotSupported(f, 'l1_norm') + + return f.rep.dom.to_sympy(result) + + def clear_denoms(self, convert=False): + """ + Clear denominators, but keep the ground domain. + + Examples + ======== + + >>> from sympy import Poly, S, QQ + >>> from sympy.abc import x + + >>> f = Poly(x/2 + S(1)/3, x, domain=QQ) + + >>> f.clear_denoms() + (6, Poly(3*x + 2, x, domain='QQ')) + >>> f.clear_denoms(convert=True) + (6, Poly(3*x + 2, x, domain='ZZ')) + + """ + f = self + + if not f.rep.dom.is_Field: + return S.One, f + + dom = f.get_domain() + if dom.has_assoc_Ring: + dom = f.rep.dom.get_ring() + + if hasattr(f.rep, 'clear_denoms'): + coeff, result = f.rep.clear_denoms() + else: # pragma: no cover + raise OperationNotSupported(f, 'clear_denoms') + + coeff, f = dom.to_sympy(coeff), f.per(result) + + if not convert or not dom.has_assoc_Ring: + return coeff, f + else: + return coeff, f.to_ring() + + def rat_clear_denoms(self, g): + """ + Clear denominators in a rational function ``f/g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = Poly(x**2/y + 1, x) + >>> g = Poly(x**3 + y, x) + + >>> p, q = f.rat_clear_denoms(g) + + >>> p + Poly(x**2 + y, x, domain='ZZ[y]') + >>> q + Poly(y*x**3 + y**2, x, domain='ZZ[y]') + + """ + f = self + + dom, per, f, g = f._unify(g) + + f = per(f) + g = per(g) + + if not (dom.is_Field and dom.has_assoc_Ring): + return f, g + + a, f = f.clear_denoms(convert=True) + b, g = g.clear_denoms(convert=True) + + f = f.mul_ground(b) + g = g.mul_ground(a) + + return f, g + + def integrate(self, *specs, **args): + """ + Computes indefinite integral of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 2*x + 1, x).integrate() + Poly(1/3*x**3 + x**2 + x, x, domain='QQ') + + >>> Poly(x*y**2 + x, x, y).integrate((0, 1), (1, 0)) + Poly(1/2*x**2*y**2 + 1/2*x**2, x, y, domain='QQ') + + """ + f = self + + if args.get('auto', True) and f.rep.dom.is_Ring: + f = f.to_field() + + if hasattr(f.rep, 'integrate'): + if not specs: + return f.per(f.rep.integrate(m=1)) + + rep = f.rep + + for spec in specs: + if isinstance(spec, tuple): + gen, m = spec + else: + gen, m = spec, 1 + + rep = rep.integrate(int(m), f._gen_to_level(gen)) + + return f.per(rep) + else: # pragma: no cover + raise OperationNotSupported(f, 'integrate') + + def diff(f, *specs, **kwargs): + """ + Computes partial derivative of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + 2*x + 1, x).diff() + Poly(2*x + 2, x, domain='ZZ') + + >>> Poly(x*y**2 + x, x, y).diff((0, 0), (1, 1)) + Poly(2*x*y, x, y, domain='ZZ') + + """ + if not kwargs.get('evaluate', True): + return Derivative(f, *specs, **kwargs) + + if hasattr(f.rep, 'diff'): + if not specs: + return f.per(f.rep.diff(m=1)) + + rep = f.rep + + for spec in specs: + if isinstance(spec, tuple): + gen, m = spec + else: + gen, m = spec, 1 + + rep = rep.diff(int(m), f._gen_to_level(gen)) + + return f.per(rep) + else: # pragma: no cover + raise OperationNotSupported(f, 'diff') + + _eval_derivative = diff + + def eval(self, x, a=None, auto=True): + """ + Evaluate ``f`` at ``a`` in the given variable. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> Poly(x**2 + 2*x + 3, x).eval(2) + 11 + + >>> Poly(2*x*y + 3*x + y + 2, x, y).eval(x, 2) + Poly(5*y + 8, y, domain='ZZ') + + >>> f = Poly(2*x*y + 3*x + y + 2*z, x, y, z) + + >>> f.eval({x: 2}) + Poly(5*y + 2*z + 6, y, z, domain='ZZ') + >>> f.eval({x: 2, y: 5}) + Poly(2*z + 31, z, domain='ZZ') + >>> f.eval({x: 2, y: 5, z: 7}) + 45 + + >>> f.eval((2, 5)) + Poly(2*z + 31, z, domain='ZZ') + >>> f(2, 5) + Poly(2*z + 31, z, domain='ZZ') + + """ + f = self + + if a is None: + if isinstance(x, dict): + mapping = x + + for gen, value in mapping.items(): + f = f.eval(gen, value) + + return f + elif isinstance(x, (tuple, list)): + values = x + + if len(values) > len(f.gens): + raise ValueError("too many values provided") + + for gen, value in zip(f.gens, values): + f = f.eval(gen, value) + + return f + else: + j, a = 0, x + else: + j = f._gen_to_level(x) + + if not hasattr(f.rep, 'eval'): # pragma: no cover + raise OperationNotSupported(f, 'eval') + + try: + result = f.rep.eval(a, j) + except CoercionFailed: + if not auto: + raise DomainError("Cannot evaluate at %s in %s" % (a, f.rep.dom)) + else: + a_domain, [a] = construct_domain([a]) + new_domain = f.get_domain().unify_with_symbols(a_domain, f.gens) + + f = f.set_domain(new_domain) + a = new_domain.convert(a, a_domain) + + result = f.rep.eval(a, j) + + return f.per(result, remove=j) + + def __call__(f, *values): + """ + Evaluate ``f`` at the give values. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y, z + + >>> f = Poly(2*x*y + 3*x + y + 2*z, x, y, z) + + >>> f(2) + Poly(5*y + 2*z + 6, y, z, domain='ZZ') + >>> f(2, 5) + Poly(2*z + 31, z, domain='ZZ') + >>> f(2, 5, 7) + 45 + + """ + return f.eval(values) + + def half_gcdex(f, g, auto=True): + """ + Half extended Euclidean algorithm of ``f`` and ``g``. + + Returns ``(s, h)`` such that ``h = gcd(f, g)`` and ``s*f = h (mod g)``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15 + >>> g = x**3 + x**2 - 4*x - 4 + + >>> Poly(f).half_gcdex(Poly(g)) + (Poly(-1/5*x + 3/5, x, domain='QQ'), Poly(x + 1, x, domain='QQ')) + + """ + dom, per, F, G = f._unify(g) + + if auto and dom.is_Ring: + F, G = F.to_field(), G.to_field() + + if hasattr(f.rep, 'half_gcdex'): + s, h = F.half_gcdex(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'half_gcdex') + + return per(s), per(h) + + def gcdex(f, g, auto=True): + """ + Extended Euclidean algorithm of ``f`` and ``g``. + + Returns ``(s, t, h)`` such that ``h = gcd(f, g)`` and ``s*f + t*g = h``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = x**4 - 2*x**3 - 6*x**2 + 12*x + 15 + >>> g = x**3 + x**2 - 4*x - 4 + + >>> Poly(f).gcdex(Poly(g)) + (Poly(-1/5*x + 3/5, x, domain='QQ'), + Poly(1/5*x**2 - 6/5*x + 2, x, domain='QQ'), + Poly(x + 1, x, domain='QQ')) + + """ + dom, per, F, G = f._unify(g) + + if auto and dom.is_Ring: + F, G = F.to_field(), G.to_field() + + if hasattr(f.rep, 'gcdex'): + s, t, h = F.gcdex(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'gcdex') + + return per(s), per(t), per(h) + + def invert(f, g, auto=True): + """ + Invert ``f`` modulo ``g`` when possible. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).invert(Poly(2*x - 1, x)) + Poly(-4/3, x, domain='QQ') + + >>> Poly(x**2 - 1, x).invert(Poly(x - 1, x)) + Traceback (most recent call last): + ... + NotInvertible: zero divisor + + """ + dom, per, F, G = f._unify(g) + + if auto and dom.is_Ring: + F, G = F.to_field(), G.to_field() + + if hasattr(f.rep, 'invert'): + result = F.invert(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'invert') + + return per(result) + + def revert(f, n): + """ + Compute ``f**(-1)`` mod ``x**n``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(1, x).revert(2) + Poly(1, x, domain='ZZ') + + >>> Poly(1 + x, x).revert(1) + Poly(1, x, domain='ZZ') + + >>> Poly(x**2 - 2, x).revert(2) + Traceback (most recent call last): + ... + NotReversible: only units are reversible in a ring + + >>> Poly(1/x, x).revert(1) + Traceback (most recent call last): + ... + PolynomialError: 1/x contains an element of the generators set + + """ + if hasattr(f.rep, 'revert'): + result = f.rep.revert(int(n)) + else: # pragma: no cover + raise OperationNotSupported(f, 'revert') + + return f.per(result) + + def subresultants(f, g): + """ + Computes the subresultant PRS of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 1, x).subresultants(Poly(x**2 - 1, x)) + [Poly(x**2 + 1, x, domain='ZZ'), + Poly(x**2 - 1, x, domain='ZZ'), + Poly(-2, x, domain='ZZ')] + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'subresultants'): + result = F.subresultants(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'subresultants') + + return list(map(per, result)) + + def resultant(f, g, includePRS=False): + """ + Computes the resultant of ``f`` and ``g`` via PRS. + + If includePRS=True, it includes the subresultant PRS in the result. + Because the PRS is used to calculate the resultant, this is more + efficient than calling :func:`subresultants` separately. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = Poly(x**2 + 1, x) + + >>> f.resultant(Poly(x**2 - 1, x)) + 4 + >>> f.resultant(Poly(x**2 - 1, x), includePRS=True) + (4, [Poly(x**2 + 1, x, domain='ZZ'), Poly(x**2 - 1, x, domain='ZZ'), + Poly(-2, x, domain='ZZ')]) + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'resultant'): + if includePRS: + result, R = F.resultant(G, includePRS=includePRS) + else: + result = F.resultant(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'resultant') + + if includePRS: + return (per(result, remove=0), list(map(per, R))) + return per(result, remove=0) + + def discriminant(f): + """ + Computes the discriminant of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + 2*x + 3, x).discriminant() + -8 + + """ + if hasattr(f.rep, 'discriminant'): + result = f.rep.discriminant() + else: # pragma: no cover + raise OperationNotSupported(f, 'discriminant') + + return f.per(result, remove=0) + + def dispersionset(f, g=None): + r"""Compute the *dispersion set* of two polynomials. + + For two polynomials `f(x)` and `g(x)` with `\deg f > 0` + and `\deg g > 0` the dispersion set `\operatorname{J}(f, g)` is defined as: + + .. math:: + \operatorname{J}(f, g) + & := \{a \in \mathbb{N}_0 | \gcd(f(x), g(x+a)) \neq 1\} \\ + & = \{a \in \mathbb{N}_0 | \deg \gcd(f(x), g(x+a)) \geq 1\} + + For a single polynomial one defines `\operatorname{J}(f) := \operatorname{J}(f, f)`. + + Examples + ======== + + >>> from sympy import poly + >>> from sympy.polys.dispersion import dispersion, dispersionset + >>> from sympy.abc import x + + Dispersion set and dispersion of a simple polynomial: + + >>> fp = poly((x - 3)*(x + 3), x) + >>> sorted(dispersionset(fp)) + [0, 6] + >>> dispersion(fp) + 6 + + Note that the definition of the dispersion is not symmetric: + + >>> fp = poly(x**4 - 3*x**2 + 1, x) + >>> gp = fp.shift(-3) + >>> sorted(dispersionset(fp, gp)) + [2, 3, 4] + >>> dispersion(fp, gp) + 4 + >>> sorted(dispersionset(gp, fp)) + [] + >>> dispersion(gp, fp) + -oo + + Computing the dispersion also works over field extensions: + + >>> from sympy import sqrt + >>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ') + >>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ') + >>> sorted(dispersionset(fp, gp)) + [2] + >>> sorted(dispersionset(gp, fp)) + [1, 4] + + We can even perform the computations for polynomials + having symbolic coefficients: + + >>> from sympy.abc import a + >>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x) + >>> sorted(dispersionset(fp)) + [0, 1] + + See Also + ======== + + dispersion + + References + ========== + + 1. [ManWright94]_ + 2. [Koepf98]_ + 3. [Abramov71]_ + 4. [Man93]_ + """ + from sympy.polys.dispersion import dispersionset + return dispersionset(f, g) + + def dispersion(f, g=None): + r"""Compute the *dispersion* of polynomials. + + For two polynomials `f(x)` and `g(x)` with `\deg f > 0` + and `\deg g > 0` the dispersion `\operatorname{dis}(f, g)` is defined as: + + .. math:: + \operatorname{dis}(f, g) + & := \max\{ J(f,g) \cup \{0\} \} \\ + & = \max\{ \{a \in \mathbb{N} | \gcd(f(x), g(x+a)) \neq 1\} \cup \{0\} \} + + and for a single polynomial `\operatorname{dis}(f) := \operatorname{dis}(f, f)`. + + Examples + ======== + + >>> from sympy import poly + >>> from sympy.polys.dispersion import dispersion, dispersionset + >>> from sympy.abc import x + + Dispersion set and dispersion of a simple polynomial: + + >>> fp = poly((x - 3)*(x + 3), x) + >>> sorted(dispersionset(fp)) + [0, 6] + >>> dispersion(fp) + 6 + + Note that the definition of the dispersion is not symmetric: + + >>> fp = poly(x**4 - 3*x**2 + 1, x) + >>> gp = fp.shift(-3) + >>> sorted(dispersionset(fp, gp)) + [2, 3, 4] + >>> dispersion(fp, gp) + 4 + >>> sorted(dispersionset(gp, fp)) + [] + >>> dispersion(gp, fp) + -oo + + Computing the dispersion also works over field extensions: + + >>> from sympy import sqrt + >>> fp = poly(x**2 + sqrt(5)*x - 1, x, domain='QQ') + >>> gp = poly(x**2 + (2 + sqrt(5))*x + sqrt(5), x, domain='QQ') + >>> sorted(dispersionset(fp, gp)) + [2] + >>> sorted(dispersionset(gp, fp)) + [1, 4] + + We can even perform the computations for polynomials + having symbolic coefficients: + + >>> from sympy.abc import a + >>> fp = poly(4*x**4 + (4*a + 8)*x**3 + (a**2 + 6*a + 4)*x**2 + (a**2 + 2*a)*x, x) + >>> sorted(dispersionset(fp)) + [0, 1] + + See Also + ======== + + dispersionset + + References + ========== + + 1. [ManWright94]_ + 2. [Koepf98]_ + 3. [Abramov71]_ + 4. [Man93]_ + """ + from sympy.polys.dispersion import dispersion + return dispersion(f, g) + + def cofactors(f, g): + """ + Returns the GCD of ``f`` and ``g`` and their cofactors. + + Returns polynomials ``(h, cff, cfg)`` such that ``h = gcd(f, g)``, and + ``cff = quo(f, h)`` and ``cfg = quo(g, h)`` are, so called, cofactors + of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).cofactors(Poly(x**2 - 3*x + 2, x)) + (Poly(x - 1, x, domain='ZZ'), + Poly(x + 1, x, domain='ZZ'), + Poly(x - 2, x, domain='ZZ')) + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'cofactors'): + h, cff, cfg = F.cofactors(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'cofactors') + + return per(h), per(cff), per(cfg) + + def gcd(f, g): + """ + Returns the polynomial GCD of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).gcd(Poly(x**2 - 3*x + 2, x)) + Poly(x - 1, x, domain='ZZ') + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'gcd'): + result = F.gcd(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'gcd') + + return per(result) + + def lcm(f, g): + """ + Returns polynomial LCM of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 1, x).lcm(Poly(x**2 - 3*x + 2, x)) + Poly(x**3 - 2*x**2 - x + 2, x, domain='ZZ') + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'lcm'): + result = F.lcm(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'lcm') + + return per(result) + + def trunc(f, p): + """ + Reduce ``f`` modulo a constant ``p``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**3 + 3*x**2 + 5*x + 7, x).trunc(3) + Poly(-x**3 - x + 1, x, domain='ZZ') + + """ + p = f.rep.dom.convert(p) + + if hasattr(f.rep, 'trunc'): + result = f.rep.trunc(p) + else: # pragma: no cover + raise OperationNotSupported(f, 'trunc') + + return f.per(result) + + def monic(self, auto=True): + """ + Divides all coefficients by ``LC(f)``. + + Examples + ======== + + >>> from sympy import Poly, ZZ + >>> from sympy.abc import x + + >>> Poly(3*x**2 + 6*x + 9, x, domain=ZZ).monic() + Poly(x**2 + 2*x + 3, x, domain='QQ') + + >>> Poly(3*x**2 + 4*x + 2, x, domain=ZZ).monic() + Poly(x**2 + 4/3*x + 2/3, x, domain='QQ') + + """ + f = self + + if auto and f.rep.dom.is_Ring: + f = f.to_field() + + if hasattr(f.rep, 'monic'): + result = f.rep.monic() + else: # pragma: no cover + raise OperationNotSupported(f, 'monic') + + return f.per(result) + + def content(f): + """ + Returns the GCD of polynomial coefficients. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(6*x**2 + 8*x + 12, x).content() + 2 + + """ + if hasattr(f.rep, 'content'): + result = f.rep.content() + else: # pragma: no cover + raise OperationNotSupported(f, 'content') + + return f.rep.dom.to_sympy(result) + + def primitive(f): + """ + Returns the content and a primitive form of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**2 + 8*x + 12, x).primitive() + (2, Poly(x**2 + 4*x + 6, x, domain='ZZ')) + + """ + if hasattr(f.rep, 'primitive'): + cont, result = f.rep.primitive() + else: # pragma: no cover + raise OperationNotSupported(f, 'primitive') + + return f.rep.dom.to_sympy(cont), f.per(result) + + def compose(f, g): + """ + Computes the functional composition of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + x, x).compose(Poly(x - 1, x)) + Poly(x**2 - x, x, domain='ZZ') + + """ + _, per, F, G = f._unify(g) + + if hasattr(f.rep, 'compose'): + result = F.compose(G) + else: # pragma: no cover + raise OperationNotSupported(f, 'compose') + + return per(result) + + def decompose(f): + """ + Computes a functional decomposition of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**4 + 2*x**3 - x - 1, x, domain='ZZ').decompose() + [Poly(x**2 - x - 1, x, domain='ZZ'), Poly(x**2 + x, x, domain='ZZ')] + + """ + if hasattr(f.rep, 'decompose'): + result = f.rep.decompose() + else: # pragma: no cover + raise OperationNotSupported(f, 'decompose') + + return list(map(f.per, result)) + + def shift(f, a): + """ + Efficiently compute Taylor shift ``f(x + a)``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 2*x + 1, x).shift(2) + Poly(x**2 + 2*x + 1, x, domain='ZZ') + + """ + if hasattr(f.rep, 'shift'): + result = f.rep.shift(a) + else: # pragma: no cover + raise OperationNotSupported(f, 'shift') + + return f.per(result) + + def transform(f, p, q): + """ + Efficiently evaluate the functional transformation ``q**n * f(p/q)``. + + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 2*x + 1, x).transform(Poly(x + 1, x), Poly(x - 1, x)) + Poly(4, x, domain='ZZ') + + """ + P, Q = p.unify(q) + F, P = f.unify(P) + F, Q = F.unify(Q) + + if hasattr(F.rep, 'transform'): + result = F.rep.transform(P.rep, Q.rep) + else: # pragma: no cover + raise OperationNotSupported(F, 'transform') + + return F.per(result) + + def sturm(self, auto=True): + """ + Computes the Sturm sequence of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 - 2*x**2 + x - 3, x).sturm() + [Poly(x**3 - 2*x**2 + x - 3, x, domain='QQ'), + Poly(3*x**2 - 4*x + 1, x, domain='QQ'), + Poly(2/9*x + 25/9, x, domain='QQ'), + Poly(-2079/4, x, domain='QQ')] + + """ + f = self + + if auto and f.rep.dom.is_Ring: + f = f.to_field() + + if hasattr(f.rep, 'sturm'): + result = f.rep.sturm() + else: # pragma: no cover + raise OperationNotSupported(f, 'sturm') + + return list(map(f.per, result)) + + def gff_list(f): + """ + Computes greatest factorial factorization of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = x**5 + 2*x**4 - x**3 - 2*x**2 + + >>> Poly(f).gff_list() + [(Poly(x, x, domain='ZZ'), 1), (Poly(x + 2, x, domain='ZZ'), 4)] + + """ + if hasattr(f.rep, 'gff_list'): + result = f.rep.gff_list() + else: # pragma: no cover + raise OperationNotSupported(f, 'gff_list') + + return [(f.per(g), k) for g, k in result] + + def norm(f): + """ + Computes the product, ``Norm(f)``, of the conjugates of + a polynomial ``f`` defined over a number field ``K``. + + Examples + ======== + + >>> from sympy import Poly, sqrt + >>> from sympy.abc import x + + >>> a, b = sqrt(2), sqrt(3) + + A polynomial over a quadratic extension. + Two conjugates x - a and x + a. + + >>> f = Poly(x - a, x, extension=a) + >>> f.norm() + Poly(x**2 - 2, x, domain='QQ') + + A polynomial over a quartic extension. + Four conjugates x - a, x - a, x + a and x + a. + + >>> f = Poly(x - a, x, extension=(a, b)) + >>> f.norm() + Poly(x**4 - 4*x**2 + 4, x, domain='QQ') + + """ + if hasattr(f.rep, 'norm'): + r = f.rep.norm() + else: # pragma: no cover + raise OperationNotSupported(f, 'norm') + + return f.per(r) + + def sqf_norm(f): + """ + Computes square-free norm of ``f``. + + Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and + ``r(x) = Norm(g(x))`` is a square-free polynomial over ``K``, + where ``a`` is the algebraic extension of the ground domain. + + Examples + ======== + + >>> from sympy import Poly, sqrt + >>> from sympy.abc import x + + >>> s, f, r = Poly(x**2 + 1, x, extension=[sqrt(3)]).sqf_norm() + + >>> s + 1 + >>> f + Poly(x**2 - 2*sqrt(3)*x + 4, x, domain='QQ') + >>> r + Poly(x**4 - 4*x**2 + 16, x, domain='QQ') + + """ + if hasattr(f.rep, 'sqf_norm'): + s, g, r = f.rep.sqf_norm() + else: # pragma: no cover + raise OperationNotSupported(f, 'sqf_norm') + + return s, f.per(g), f.per(r) + + def sqf_part(f): + """ + Computes square-free part of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**3 - 3*x - 2, x).sqf_part() + Poly(x**2 - x - 2, x, domain='ZZ') + + """ + if hasattr(f.rep, 'sqf_part'): + result = f.rep.sqf_part() + else: # pragma: no cover + raise OperationNotSupported(f, 'sqf_part') + + return f.per(result) + + def sqf_list(f, all=False): + """ + Returns a list of square-free factors of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = 2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16 + + >>> Poly(f).sqf_list() + (2, [(Poly(x + 1, x, domain='ZZ'), 2), + (Poly(x + 2, x, domain='ZZ'), 3)]) + + >>> Poly(f).sqf_list(all=True) + (2, [(Poly(1, x, domain='ZZ'), 1), + (Poly(x + 1, x, domain='ZZ'), 2), + (Poly(x + 2, x, domain='ZZ'), 3)]) + + """ + if hasattr(f.rep, 'sqf_list'): + coeff, factors = f.rep.sqf_list(all) + else: # pragma: no cover + raise OperationNotSupported(f, 'sqf_list') + + return f.rep.dom.to_sympy(coeff), [(f.per(g), k) for g, k in factors] + + def sqf_list_include(f, all=False): + """ + Returns a list of square-free factors of ``f``. + + Examples + ======== + + >>> from sympy import Poly, expand + >>> from sympy.abc import x + + >>> f = expand(2*(x + 1)**3*x**4) + >>> f + 2*x**7 + 6*x**6 + 6*x**5 + 2*x**4 + + >>> Poly(f).sqf_list_include() + [(Poly(2, x, domain='ZZ'), 1), + (Poly(x + 1, x, domain='ZZ'), 3), + (Poly(x, x, domain='ZZ'), 4)] + + >>> Poly(f).sqf_list_include(all=True) + [(Poly(2, x, domain='ZZ'), 1), + (Poly(1, x, domain='ZZ'), 2), + (Poly(x + 1, x, domain='ZZ'), 3), + (Poly(x, x, domain='ZZ'), 4)] + + """ + if hasattr(f.rep, 'sqf_list_include'): + factors = f.rep.sqf_list_include(all) + else: # pragma: no cover + raise OperationNotSupported(f, 'sqf_list_include') + + return [(f.per(g), k) for g, k in factors] + + def factor_list(f): + """ + Returns a list of irreducible factors of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = 2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y + + >>> Poly(f).factor_list() + (2, [(Poly(x + y, x, y, domain='ZZ'), 1), + (Poly(x**2 + 1, x, y, domain='ZZ'), 2)]) + + """ + if hasattr(f.rep, 'factor_list'): + try: + coeff, factors = f.rep.factor_list() + except DomainError: + return S.One, [(f, 1)] + else: # pragma: no cover + raise OperationNotSupported(f, 'factor_list') + + return f.rep.dom.to_sympy(coeff), [(f.per(g), k) for g, k in factors] + + def factor_list_include(f): + """ + Returns a list of irreducible factors of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> f = 2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y + + >>> Poly(f).factor_list_include() + [(Poly(2*x + 2*y, x, y, domain='ZZ'), 1), + (Poly(x**2 + 1, x, y, domain='ZZ'), 2)] + + """ + if hasattr(f.rep, 'factor_list_include'): + try: + factors = f.rep.factor_list_include() + except DomainError: + return [(f, 1)] + else: # pragma: no cover + raise OperationNotSupported(f, 'factor_list_include') + + return [(f.per(g), k) for g, k in factors] + + def intervals(f, all=False, eps=None, inf=None, sup=None, fast=False, sqf=False): + """ + Compute isolating intervals for roots of ``f``. + + For real roots the Vincent-Akritas-Strzebonski (VAS) continued fractions method is used. + + References + ========== + .. [#] Alkiviadis G. Akritas and Adam W. Strzebonski: A Comparative Study of Two Real Root + Isolation Methods . Nonlinear Analysis: Modelling and Control, Vol. 10, No. 4, 297-304, 2005. + .. [#] Alkiviadis G. Akritas, Adam W. Strzebonski and Panagiotis S. Vigklas: Improving the + Performance of the Continued Fractions Method Using new Bounds of Positive Roots. Nonlinear + Analysis: Modelling and Control, Vol. 13, No. 3, 265-279, 2008. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 3, x).intervals() + [((-2, -1), 1), ((1, 2), 1)] + >>> Poly(x**2 - 3, x).intervals(eps=1e-2) + [((-26/15, -19/11), 1), ((19/11, 26/15), 1)] + + """ + if eps is not None: + eps = QQ.convert(eps) + + if eps <= 0: + raise ValueError("'eps' must be a positive rational") + + if inf is not None: + inf = QQ.convert(inf) + if sup is not None: + sup = QQ.convert(sup) + + if hasattr(f.rep, 'intervals'): + result = f.rep.intervals( + all=all, eps=eps, inf=inf, sup=sup, fast=fast, sqf=sqf) + else: # pragma: no cover + raise OperationNotSupported(f, 'intervals') + + if sqf: + def _real(interval): + s, t = interval + return (QQ.to_sympy(s), QQ.to_sympy(t)) + + if not all: + return list(map(_real, result)) + + def _complex(rectangle): + (u, v), (s, t) = rectangle + return (QQ.to_sympy(u) + I*QQ.to_sympy(v), + QQ.to_sympy(s) + I*QQ.to_sympy(t)) + + real_part, complex_part = result + + return list(map(_real, real_part)), list(map(_complex, complex_part)) + else: + def _real(interval): + (s, t), k = interval + return ((QQ.to_sympy(s), QQ.to_sympy(t)), k) + + if not all: + return list(map(_real, result)) + + def _complex(rectangle): + ((u, v), (s, t)), k = rectangle + return ((QQ.to_sympy(u) + I*QQ.to_sympy(v), + QQ.to_sympy(s) + I*QQ.to_sympy(t)), k) + + real_part, complex_part = result + + return list(map(_real, real_part)), list(map(_complex, complex_part)) + + def refine_root(f, s, t, eps=None, steps=None, fast=False, check_sqf=False): + """ + Refine an isolating interval of a root to the given precision. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 3, x).refine_root(1, 2, eps=1e-2) + (19/11, 26/15) + + """ + if check_sqf and not f.is_sqf: + raise PolynomialError("only square-free polynomials supported") + + s, t = QQ.convert(s), QQ.convert(t) + + if eps is not None: + eps = QQ.convert(eps) + + if eps <= 0: + raise ValueError("'eps' must be a positive rational") + + if steps is not None: + steps = int(steps) + elif eps is None: + steps = 1 + + if hasattr(f.rep, 'refine_root'): + S, T = f.rep.refine_root(s, t, eps=eps, steps=steps, fast=fast) + else: # pragma: no cover + raise OperationNotSupported(f, 'refine_root') + + return QQ.to_sympy(S), QQ.to_sympy(T) + + def count_roots(f, inf=None, sup=None): + """ + Return the number of roots of ``f`` in ``[inf, sup]`` interval. + + Examples + ======== + + >>> from sympy import Poly, I + >>> from sympy.abc import x + + >>> Poly(x**4 - 4, x).count_roots(-3, 3) + 2 + >>> Poly(x**4 - 4, x).count_roots(0, 1 + 3*I) + 1 + + """ + inf_real, sup_real = True, True + + if inf is not None: + inf = sympify(inf) + + if inf is S.NegativeInfinity: + inf = None + else: + re, im = inf.as_real_imag() + + if not im: + inf = QQ.convert(inf) + else: + inf, inf_real = list(map(QQ.convert, (re, im))), False + + if sup is not None: + sup = sympify(sup) + + if sup is S.Infinity: + sup = None + else: + re, im = sup.as_real_imag() + + if not im: + sup = QQ.convert(sup) + else: + sup, sup_real = list(map(QQ.convert, (re, im))), False + + if inf_real and sup_real: + if hasattr(f.rep, 'count_real_roots'): + count = f.rep.count_real_roots(inf=inf, sup=sup) + else: # pragma: no cover + raise OperationNotSupported(f, 'count_real_roots') + else: + if inf_real and inf is not None: + inf = (inf, QQ.zero) + + if sup_real and sup is not None: + sup = (sup, QQ.zero) + + if hasattr(f.rep, 'count_complex_roots'): + count = f.rep.count_complex_roots(inf=inf, sup=sup) + else: # pragma: no cover + raise OperationNotSupported(f, 'count_complex_roots') + + return Integer(count) + + def root(f, index, radicals=True): + """ + Get an indexed root of a polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = Poly(2*x**3 - 7*x**2 + 4*x + 4) + + >>> f.root(0) + -1/2 + >>> f.root(1) + 2 + >>> f.root(2) + 2 + >>> f.root(3) + Traceback (most recent call last): + ... + IndexError: root index out of [-3, 2] range, got 3 + + >>> Poly(x**5 + x + 1).root(0) + CRootOf(x**3 - x**2 + 1, 0) + + """ + return sympy.polys.rootoftools.rootof(f, index, radicals=radicals) + + def real_roots(f, multiple=True, radicals=True): + """ + Return a list of real roots with multiplicities. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**3 - 7*x**2 + 4*x + 4).real_roots() + [-1/2, 2, 2] + >>> Poly(x**3 + x + 1).real_roots() + [CRootOf(x**3 + x + 1, 0)] + + """ + reals = sympy.polys.rootoftools.CRootOf.real_roots(f, radicals=radicals) + + if multiple: + return reals + else: + return group(reals, multiple=False) + + def all_roots(f, multiple=True, radicals=True): + """ + Return a list of real and complex roots with multiplicities. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**3 - 7*x**2 + 4*x + 4).all_roots() + [-1/2, 2, 2] + >>> Poly(x**3 + x + 1).all_roots() + [CRootOf(x**3 + x + 1, 0), + CRootOf(x**3 + x + 1, 1), + CRootOf(x**3 + x + 1, 2)] + + """ + roots = sympy.polys.rootoftools.CRootOf.all_roots(f, radicals=radicals) + + if multiple: + return roots + else: + return group(roots, multiple=False) + + def nroots(f, n=15, maxsteps=50, cleanup=True): + """ + Compute numerical approximations of roots of ``f``. + + Parameters + ========== + + n ... the number of digits to calculate + maxsteps ... the maximum number of iterations to do + + If the accuracy `n` cannot be reached in `maxsteps`, it will raise an + exception. You need to rerun with higher maxsteps. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 3).nroots(n=15) + [-1.73205080756888, 1.73205080756888] + >>> Poly(x**2 - 3).nroots(n=30) + [-1.73205080756887729352744634151, 1.73205080756887729352744634151] + + """ + if f.is_multivariate: + raise MultivariatePolynomialError( + "Cannot compute numerical roots of %s" % f) + + if f.degree() <= 0: + return [] + + # For integer and rational coefficients, convert them to integers only + # (for accuracy). Otherwise just try to convert the coefficients to + # mpmath.mpc and raise an exception if the conversion fails. + if f.rep.dom is ZZ: + coeffs = [int(coeff) for coeff in f.all_coeffs()] + elif f.rep.dom is QQ: + denoms = [coeff.q for coeff in f.all_coeffs()] + fac = ilcm(*denoms) + coeffs = [int(coeff*fac) for coeff in f.all_coeffs()] + else: + coeffs = [coeff.evalf(n=n).as_real_imag() + for coeff in f.all_coeffs()] + try: + coeffs = [mpmath.mpc(*coeff) for coeff in coeffs] + except TypeError: + raise DomainError("Numerical domain expected, got %s" % \ + f.rep.dom) + + dps = mpmath.mp.dps + mpmath.mp.dps = n + + from sympy.functions.elementary.complexes import sign + try: + # We need to add extra precision to guard against losing accuracy. + # 10 times the degree of the polynomial seems to work well. + roots = mpmath.polyroots(coeffs, maxsteps=maxsteps, + cleanup=cleanup, error=False, extraprec=f.degree()*10) + + # Mpmath puts real roots first, then complex ones (as does all_roots) + # so we make sure this convention holds here, too. + roots = list(map(sympify, + sorted(roots, key=lambda r: (1 if r.imag else 0, r.real, abs(r.imag), sign(r.imag))))) + except NoConvergence: + try: + # If roots did not converge try again with more extra precision. + roots = mpmath.polyroots(coeffs, maxsteps=maxsteps, + cleanup=cleanup, error=False, extraprec=f.degree()*15) + roots = list(map(sympify, + sorted(roots, key=lambda r: (1 if r.imag else 0, r.real, abs(r.imag), sign(r.imag))))) + except NoConvergence: + raise NoConvergence( + 'convergence to root failed; try n < %s or maxsteps > %s' % ( + n, maxsteps)) + finally: + mpmath.mp.dps = dps + + return roots + + def ground_roots(f): + """ + Compute roots of ``f`` by factorization in the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**6 - 4*x**4 + 4*x**3 - x**2).ground_roots() + {0: 2, 1: 2} + + """ + if f.is_multivariate: + raise MultivariatePolynomialError( + "Cannot compute ground roots of %s" % f) + + roots = {} + + for factor, k in f.factor_list()[1]: + if factor.is_linear: + a, b = factor.all_coeffs() + roots[-b/a] = k + + return roots + + def nth_power_roots_poly(f, n): + """ + Construct a polynomial with n-th powers of roots of ``f``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = Poly(x**4 - x**2 + 1) + + >>> f.nth_power_roots_poly(2) + Poly(x**4 - 2*x**3 + 3*x**2 - 2*x + 1, x, domain='ZZ') + >>> f.nth_power_roots_poly(3) + Poly(x**4 + 2*x**2 + 1, x, domain='ZZ') + >>> f.nth_power_roots_poly(4) + Poly(x**4 + 2*x**3 + 3*x**2 + 2*x + 1, x, domain='ZZ') + >>> f.nth_power_roots_poly(12) + Poly(x**4 - 4*x**3 + 6*x**2 - 4*x + 1, x, domain='ZZ') + + """ + if f.is_multivariate: + raise MultivariatePolynomialError( + "must be a univariate polynomial") + + N = sympify(n) + + if N.is_Integer and N >= 1: + n = int(N) + else: + raise ValueError("'n' must an integer and n >= 1, got %s" % n) + + x = f.gen + t = Dummy('t') + + r = f.resultant(f.__class__.from_expr(x**n - t, x, t)) + + return r.replace(t, x) + + def same_root(f, a, b): + """ + Decide whether two roots of this polynomial are equal. + + Examples + ======== + + >>> from sympy import Poly, cyclotomic_poly, exp, I, pi + >>> f = Poly(cyclotomic_poly(5)) + >>> r0 = exp(2*I*pi/5) + >>> indices = [i for i, r in enumerate(f.all_roots()) if f.same_root(r, r0)] + >>> print(indices) + [3] + + Raises + ====== + + DomainError + If the domain of the polynomial is not :ref:`ZZ`, :ref:`QQ`, + :ref:`RR`, or :ref:`CC`. + MultivariatePolynomialError + If the polynomial is not univariate. + PolynomialError + If the polynomial is of degree < 2. + + """ + if f.is_multivariate: + raise MultivariatePolynomialError( + "Must be a univariate polynomial") + + dom_delta_sq = f.rep.mignotte_sep_bound_squared() + delta_sq = f.domain.get_field().to_sympy(dom_delta_sq) + # We have delta_sq = delta**2, where delta is a lower bound on the + # minimum separation between any two roots of this polynomial. + # Let eps = delta/3, and define eps_sq = eps**2 = delta**2/9. + eps_sq = delta_sq / 9 + + r, _, _, _ = evalf(1/eps_sq, 1, {}) + n = fastlog(r) + # Then 2^n > 1/eps**2. + m = (n // 2) + (n % 2) + # Then 2^(-m) < eps. + ev = lambda x: quad_to_mpmath(_evalf_with_bounded_error(x, m=m)) + + # Then for any complex numbers a, b we will have + # |a - ev(a)| < eps and |b - ev(b)| < eps. + # So if |ev(a) - ev(b)|**2 < eps**2, then + # |ev(a) - ev(b)| < eps, hence |a - b| < 3*eps = delta. + A, B = ev(a), ev(b) + return (A.real - B.real)**2 + (A.imag - B.imag)**2 < eps_sq + + def cancel(f, g, include=False): + """ + Cancel common factors in a rational function ``f/g``. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**2 - 2, x).cancel(Poly(x**2 - 2*x + 1, x)) + (1, Poly(2*x + 2, x, domain='ZZ'), Poly(x - 1, x, domain='ZZ')) + + >>> Poly(2*x**2 - 2, x).cancel(Poly(x**2 - 2*x + 1, x), include=True) + (Poly(2*x + 2, x, domain='ZZ'), Poly(x - 1, x, domain='ZZ')) + + """ + dom, per, F, G = f._unify(g) + + if hasattr(F, 'cancel'): + result = F.cancel(G, include=include) + else: # pragma: no cover + raise OperationNotSupported(f, 'cancel') + + if not include: + if dom.has_assoc_Ring: + dom = dom.get_ring() + + cp, cq, p, q = result + + cp = dom.to_sympy(cp) + cq = dom.to_sympy(cq) + + return cp/cq, per(p), per(q) + else: + return tuple(map(per, result)) + + def make_monic_over_integers_by_scaling_roots(f): + """ + Turn any univariate polynomial over :ref:`QQ` or :ref:`ZZ` into a monic + polynomial over :ref:`ZZ`, by scaling the roots as necessary. + + Explanation + =========== + + This operation can be performed whether or not *f* is irreducible; when + it is, this can be understood as determining an algebraic integer + generating the same field as a root of *f*. + + Examples + ======== + + >>> from sympy import Poly, S + >>> from sympy.abc import x + >>> f = Poly(x**2/2 + S(1)/4 * x + S(1)/8, x, domain='QQ') + >>> f.make_monic_over_integers_by_scaling_roots() + (Poly(x**2 + 2*x + 4, x, domain='ZZ'), 4) + + Returns + ======= + + Pair ``(g, c)`` + g is the polynomial + + c is the integer by which the roots had to be scaled + + """ + if not f.is_univariate or f.domain not in [ZZ, QQ]: + raise ValueError('Polynomial must be univariate over ZZ or QQ.') + if f.is_monic and f.domain == ZZ: + return f, ZZ.one + else: + fm = f.monic() + c, _ = fm.clear_denoms() + return fm.transform(Poly(fm.gen), c).to_ring(), c + + def galois_group(f, by_name=False, max_tries=30, randomize=False): + """ + Compute the Galois group of this polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + >>> f = Poly(x**4 - 2) + >>> G, _ = f.galois_group(by_name=True) + >>> print(G) + S4TransitiveSubgroups.D4 + + See Also + ======== + + sympy.polys.numberfields.galoisgroups.galois_group + + """ + from sympy.polys.numberfields.galoisgroups import ( + _galois_group_degree_3, _galois_group_degree_4_lookup, + _galois_group_degree_5_lookup_ext_factor, + _galois_group_degree_6_lookup, + ) + if (not f.is_univariate + or not f.is_irreducible + or f.domain not in [ZZ, QQ] + ): + raise ValueError('Polynomial must be irreducible and univariate over ZZ or QQ.') + gg = { + 3: _galois_group_degree_3, + 4: _galois_group_degree_4_lookup, + 5: _galois_group_degree_5_lookup_ext_factor, + 6: _galois_group_degree_6_lookup, + } + max_supported = max(gg.keys()) + n = f.degree() + if n > max_supported: + raise ValueError(f"Only polynomials up to degree {max_supported} are supported.") + elif n < 1: + raise ValueError("Constant polynomial has no Galois group.") + elif n == 1: + from sympy.combinatorics.galois import S1TransitiveSubgroups + name, alt = S1TransitiveSubgroups.S1, True + elif n == 2: + from sympy.combinatorics.galois import S2TransitiveSubgroups + name, alt = S2TransitiveSubgroups.S2, False + else: + g, _ = f.make_monic_over_integers_by_scaling_roots() + name, alt = gg[n](g, max_tries=max_tries, randomize=randomize) + G = name if by_name else name.get_perm_group() + return G, alt + + @property + def is_zero(f): + """ + Returns ``True`` if ``f`` is a zero polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(0, x).is_zero + True + >>> Poly(1, x).is_zero + False + + """ + return f.rep.is_zero + + @property + def is_one(f): + """ + Returns ``True`` if ``f`` is a unit polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(0, x).is_one + False + >>> Poly(1, x).is_one + True + + """ + return f.rep.is_one + + @property + def is_sqf(f): + """ + Returns ``True`` if ``f`` is a square-free polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 - 2*x + 1, x).is_sqf + False + >>> Poly(x**2 - 1, x).is_sqf + True + + """ + return f.rep.is_sqf + + @property + def is_monic(f): + """ + Returns ``True`` if the leading coefficient of ``f`` is one. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x + 2, x).is_monic + True + >>> Poly(2*x + 2, x).is_monic + False + + """ + return f.rep.is_monic + + @property + def is_primitive(f): + """ + Returns ``True`` if GCD of the coefficients of ``f`` is one. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(2*x**2 + 6*x + 12, x).is_primitive + False + >>> Poly(x**2 + 3*x + 6, x).is_primitive + True + + """ + return f.rep.is_primitive + + @property + def is_ground(f): + """ + Returns ``True`` if ``f`` is an element of the ground domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x, x).is_ground + False + >>> Poly(2, x).is_ground + True + >>> Poly(y, x).is_ground + True + + """ + return f.rep.is_ground + + @property + def is_linear(f): + """ + Returns ``True`` if ``f`` is linear in all its variables. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x + y + 2, x, y).is_linear + True + >>> Poly(x*y + 2, x, y).is_linear + False + + """ + return f.rep.is_linear + + @property + def is_quadratic(f): + """ + Returns ``True`` if ``f`` is quadratic in all its variables. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x*y + 2, x, y).is_quadratic + True + >>> Poly(x*y**2 + 2, x, y).is_quadratic + False + + """ + return f.rep.is_quadratic + + @property + def is_monomial(f): + """ + Returns ``True`` if ``f`` is zero or has only one term. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(3*x**2, x).is_monomial + True + >>> Poly(3*x**2 + 1, x).is_monomial + False + + """ + return f.rep.is_monomial + + @property + def is_homogeneous(f): + """ + Returns ``True`` if ``f`` is a homogeneous polynomial. + + A homogeneous polynomial is a polynomial whose all monomials with + non-zero coefficients have the same total degree. If you want not + only to check if a polynomial is homogeneous but also compute its + homogeneous order, then use :func:`Poly.homogeneous_order`. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + x*y, x, y).is_homogeneous + True + >>> Poly(x**3 + x*y, x, y).is_homogeneous + False + + """ + return f.rep.is_homogeneous + + @property + def is_irreducible(f): + """ + Returns ``True`` if ``f`` has no factors over its domain. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> Poly(x**2 + x + 1, x, modulus=2).is_irreducible + True + >>> Poly(x**2 + 1, x, modulus=2).is_irreducible + False + + """ + return f.rep.is_irreducible + + @property + def is_univariate(f): + """ + Returns ``True`` if ``f`` is a univariate polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + x + 1, x).is_univariate + True + >>> Poly(x*y**2 + x*y + 1, x, y).is_univariate + False + >>> Poly(x*y**2 + x*y + 1, x).is_univariate + True + >>> Poly(x**2 + x + 1, x, y).is_univariate + False + + """ + return len(f.gens) == 1 + + @property + def is_multivariate(f): + """ + Returns ``True`` if ``f`` is a multivariate polynomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x, y + + >>> Poly(x**2 + x + 1, x).is_multivariate + False + >>> Poly(x*y**2 + x*y + 1, x, y).is_multivariate + True + >>> Poly(x*y**2 + x*y + 1, x).is_multivariate + False + >>> Poly(x**2 + x + 1, x, y).is_multivariate + True + + """ + return len(f.gens) != 1 + + @property + def is_cyclotomic(f): + """ + Returns ``True`` if ``f`` is a cyclotomic polnomial. + + Examples + ======== + + >>> from sympy import Poly + >>> from sympy.abc import x + + >>> f = x**16 + x**14 - x**10 + x**8 - x**6 + x**2 + 1 + + >>> Poly(f).is_cyclotomic + False + + >>> g = x**16 + x**14 - x**10 - x**8 - x**6 + x**2 + 1 + + >>> Poly(g).is_cyclotomic + True + + """ + return f.rep.is_cyclotomic + + def __abs__(f): + return f.abs() + + def __neg__(f): + return f.neg() + + @_polifyit + def __add__(f, g): + return f.add(g) + + @_polifyit + def __radd__(f, g): + return g.add(f) + + @_polifyit + def __sub__(f, g): + return f.sub(g) + + @_polifyit + def __rsub__(f, g): + return g.sub(f) + + @_polifyit + def __mul__(f, g): + return f.mul(g) + + @_polifyit + def __rmul__(f, g): + return g.mul(f) + + @_sympifyit('n', NotImplemented) + def __pow__(f, n): + if n.is_Integer and n >= 0: + return f.pow(n) + else: + return NotImplemented + + @_polifyit + def __divmod__(f, g): + return f.div(g) + + @_polifyit + def __rdivmod__(f, g): + return g.div(f) + + @_polifyit + def __mod__(f, g): + return f.rem(g) + + @_polifyit + def __rmod__(f, g): + return g.rem(f) + + @_polifyit + def __floordiv__(f, g): + return f.quo(g) + + @_polifyit + def __rfloordiv__(f, g): + return g.quo(f) + + @_sympifyit('g', NotImplemented) + def __truediv__(f, g): + return f.as_expr()/g.as_expr() + + @_sympifyit('g', NotImplemented) + def __rtruediv__(f, g): + return g.as_expr()/f.as_expr() + + @_sympifyit('other', NotImplemented) + def __eq__(self, other): + f, g = self, other + + if not g.is_Poly: + try: + g = f.__class__(g, f.gens, domain=f.get_domain()) + except (PolynomialError, DomainError, CoercionFailed): + return False + + if f.gens != g.gens: + return False + + if f.rep.dom != g.rep.dom: + return False + + return f.rep == g.rep + + @_sympifyit('g', NotImplemented) + def __ne__(f, g): + return not f == g + + def __bool__(f): + return not f.is_zero + + def eq(f, g, strict=False): + if not strict: + return f == g + else: + return f._strict_eq(sympify(g)) + + def ne(f, g, strict=False): + return not f.eq(g, strict=strict) + + def _strict_eq(f, g): + return isinstance(g, f.__class__) and f.gens == g.gens and f.rep.eq(g.rep, strict=True) + + +@public +class PurePoly(Poly): + """Class for representing pure polynomials. """ + + def _hashable_content(self): + """Allow SymPy to hash Poly instances. """ + return (self.rep,) + + def __hash__(self): + return super().__hash__() + + @property + def free_symbols(self): + """ + Free symbols of a polynomial. + + Examples + ======== + + >>> from sympy import PurePoly + >>> from sympy.abc import x, y + + >>> PurePoly(x**2 + 1).free_symbols + set() + >>> PurePoly(x**2 + y).free_symbols + set() + >>> PurePoly(x**2 + y, x).free_symbols + {y} + + """ + return self.free_symbols_in_domain + + @_sympifyit('other', NotImplemented) + def __eq__(self, other): + f, g = self, other + + if not g.is_Poly: + try: + g = f.__class__(g, f.gens, domain=f.get_domain()) + except (PolynomialError, DomainError, CoercionFailed): + return False + + if len(f.gens) != len(g.gens): + return False + + if f.rep.dom != g.rep.dom: + try: + dom = f.rep.dom.unify(g.rep.dom, f.gens) + except UnificationFailed: + return False + + f = f.set_domain(dom) + g = g.set_domain(dom) + + return f.rep == g.rep + + def _strict_eq(f, g): + return isinstance(g, f.__class__) and f.rep.eq(g.rep, strict=True) + + def _unify(f, g): + g = sympify(g) + + if not g.is_Poly: + try: + return f.rep.dom, f.per, f.rep, f.rep.per(f.rep.dom.from_sympy(g)) + except CoercionFailed: + raise UnificationFailed("Cannot unify %s with %s" % (f, g)) + + if len(f.gens) != len(g.gens): + raise UnificationFailed("Cannot unify %s with %s" % (f, g)) + + if not (isinstance(f.rep, DMP) and isinstance(g.rep, DMP)): + raise UnificationFailed("Cannot unify %s with %s" % (f, g)) + + cls = f.__class__ + gens = f.gens + + dom = f.rep.dom.unify(g.rep.dom, gens) + + F = f.rep.convert(dom) + G = g.rep.convert(dom) + + def per(rep, dom=dom, gens=gens, remove=None): + if remove is not None: + gens = gens[:remove] + gens[remove + 1:] + + if not gens: + return dom.to_sympy(rep) + + return cls.new(rep, *gens) + + return dom, per, F, G + + +@public +def poly_from_expr(expr, *gens, **args): + """Construct a polynomial from an expression. """ + opt = options.build_options(gens, args) + return _poly_from_expr(expr, opt) + + +def _poly_from_expr(expr, opt): + """Construct a polynomial from an expression. """ + orig, expr = expr, sympify(expr) + + if not isinstance(expr, Basic): + raise PolificationFailed(opt, orig, expr) + elif expr.is_Poly: + poly = expr.__class__._from_poly(expr, opt) + + opt.gens = poly.gens + opt.domain = poly.domain + + if opt.polys is None: + opt.polys = True + + return poly, opt + elif opt.expand: + expr = expr.expand() + + rep, opt = _dict_from_expr(expr, opt) + if not opt.gens: + raise PolificationFailed(opt, orig, expr) + + monoms, coeffs = list(zip(*list(rep.items()))) + domain = opt.domain + + if domain is None: + opt.domain, coeffs = construct_domain(coeffs, opt=opt) + else: + coeffs = list(map(domain.from_sympy, coeffs)) + + rep = dict(list(zip(monoms, coeffs))) + poly = Poly._from_dict(rep, opt) + + if opt.polys is None: + opt.polys = False + + return poly, opt + + +@public +def parallel_poly_from_expr(exprs, *gens, **args): + """Construct polynomials from expressions. """ + opt = options.build_options(gens, args) + return _parallel_poly_from_expr(exprs, opt) + + +def _parallel_poly_from_expr(exprs, opt): + """Construct polynomials from expressions. """ + if len(exprs) == 2: + f, g = exprs + + if isinstance(f, Poly) and isinstance(g, Poly): + f = f.__class__._from_poly(f, opt) + g = g.__class__._from_poly(g, opt) + + f, g = f.unify(g) + + opt.gens = f.gens + opt.domain = f.domain + + if opt.polys is None: + opt.polys = True + + return [f, g], opt + + origs, exprs = list(exprs), [] + _exprs, _polys = [], [] + + failed = False + + for i, expr in enumerate(origs): + expr = sympify(expr) + + if isinstance(expr, Basic): + if expr.is_Poly: + _polys.append(i) + else: + _exprs.append(i) + + if opt.expand: + expr = expr.expand() + else: + failed = True + + exprs.append(expr) + + if failed: + raise PolificationFailed(opt, origs, exprs, True) + + if _polys: + # XXX: this is a temporary solution + for i in _polys: + exprs[i] = exprs[i].as_expr() + + reps, opt = _parallel_dict_from_expr(exprs, opt) + if not opt.gens: + raise PolificationFailed(opt, origs, exprs, True) + + from sympy.functions.elementary.piecewise import Piecewise + for k in opt.gens: + if isinstance(k, Piecewise): + raise PolynomialError("Piecewise generators do not make sense") + + coeffs_list, lengths = [], [] + + all_monoms = [] + all_coeffs = [] + + for rep in reps: + monoms, coeffs = list(zip(*list(rep.items()))) + + coeffs_list.extend(coeffs) + all_monoms.append(monoms) + + lengths.append(len(coeffs)) + + domain = opt.domain + + if domain is None: + opt.domain, coeffs_list = construct_domain(coeffs_list, opt=opt) + else: + coeffs_list = list(map(domain.from_sympy, coeffs_list)) + + for k in lengths: + all_coeffs.append(coeffs_list[:k]) + coeffs_list = coeffs_list[k:] + + polys = [] + + for monoms, coeffs in zip(all_monoms, all_coeffs): + rep = dict(list(zip(monoms, coeffs))) + poly = Poly._from_dict(rep, opt) + polys.append(poly) + + if opt.polys is None: + opt.polys = bool(_polys) + + return polys, opt + + +def _update_args(args, key, value): + """Add a new ``(key, value)`` pair to arguments ``dict``. """ + args = dict(args) + + if key not in args: + args[key] = value + + return args + + +@public +def degree(f, gen=0): + """ + Return the degree of ``f`` in the given variable. + + The degree of 0 is negative infinity. + + Examples + ======== + + >>> from sympy import degree + >>> from sympy.abc import x, y + + >>> degree(x**2 + y*x + 1, gen=x) + 2 + >>> degree(x**2 + y*x + 1, gen=y) + 1 + >>> degree(0, x) + -oo + + See also + ======== + + sympy.polys.polytools.Poly.total_degree + degree_list + """ + + f = sympify(f, strict=True) + gen_is_Num = sympify(gen, strict=True).is_Number + if f.is_Poly: + p = f + isNum = p.as_expr().is_Number + else: + isNum = f.is_Number + if not isNum: + if gen_is_Num: + p, _ = poly_from_expr(f) + else: + p, _ = poly_from_expr(f, gen) + + if isNum: + return S.Zero if f else S.NegativeInfinity + + if not gen_is_Num: + if f.is_Poly and gen not in p.gens: + # try recast without explicit gens + p, _ = poly_from_expr(f.as_expr()) + if gen not in p.gens: + return S.Zero + elif not f.is_Poly and len(f.free_symbols) > 1: + raise TypeError(filldedent(''' + A symbolic generator of interest is required for a multivariate + expression like func = %s, e.g. degree(func, gen = %s) instead of + degree(func, gen = %s). + ''' % (f, next(ordered(f.free_symbols)), gen))) + result = p.degree(gen) + return Integer(result) if isinstance(result, int) else S.NegativeInfinity + + +@public +def total_degree(f, *gens): + """ + Return the total_degree of ``f`` in the given variables. + + Examples + ======== + >>> from sympy import total_degree, Poly + >>> from sympy.abc import x, y + + >>> total_degree(1) + 0 + >>> total_degree(x + x*y) + 2 + >>> total_degree(x + x*y, x) + 1 + + If the expression is a Poly and no variables are given + then the generators of the Poly will be used: + + >>> p = Poly(x + x*y, y) + >>> total_degree(p) + 1 + + To deal with the underlying expression of the Poly, convert + it to an Expr: + + >>> total_degree(p.as_expr()) + 2 + + This is done automatically if any variables are given: + + >>> total_degree(p, x) + 1 + + See also + ======== + degree + """ + + p = sympify(f) + if p.is_Poly: + p = p.as_expr() + if p.is_Number: + rv = 0 + else: + if f.is_Poly: + gens = gens or f.gens + rv = Poly(p, gens).total_degree() + + return Integer(rv) + + +@public +def degree_list(f, *gens, **args): + """ + Return a list of degrees of ``f`` in all variables. + + Examples + ======== + + >>> from sympy import degree_list + >>> from sympy.abc import x, y + + >>> degree_list(x**2 + y*x + 1) + (2, 1) + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('degree_list', 1, exc) + + degrees = F.degree_list() + + return tuple(map(Integer, degrees)) + + +@public +def LC(f, *gens, **args): + """ + Return the leading coefficient of ``f``. + + Examples + ======== + + >>> from sympy import LC + >>> from sympy.abc import x, y + + >>> LC(4*x**2 + 2*x*y**2 + x*y + 3*y) + 4 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('LC', 1, exc) + + return F.LC(order=opt.order) + + +@public +def LM(f, *gens, **args): + """ + Return the leading monomial of ``f``. + + Examples + ======== + + >>> from sympy import LM + >>> from sympy.abc import x, y + + >>> LM(4*x**2 + 2*x*y**2 + x*y + 3*y) + x**2 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('LM', 1, exc) + + monom = F.LM(order=opt.order) + return monom.as_expr() + + +@public +def LT(f, *gens, **args): + """ + Return the leading term of ``f``. + + Examples + ======== + + >>> from sympy import LT + >>> from sympy.abc import x, y + + >>> LT(4*x**2 + 2*x*y**2 + x*y + 3*y) + 4*x**2 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('LT', 1, exc) + + monom, coeff = F.LT(order=opt.order) + return coeff*monom.as_expr() + + +@public +def pdiv(f, g, *gens, **args): + """ + Compute polynomial pseudo-division of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import pdiv + >>> from sympy.abc import x + + >>> pdiv(x**2 + 1, 2*x - 4) + (2*x + 4, 20) + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('pdiv', 2, exc) + + q, r = F.pdiv(G) + + if not opt.polys: + return q.as_expr(), r.as_expr() + else: + return q, r + + +@public +def prem(f, g, *gens, **args): + """ + Compute polynomial pseudo-remainder of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import prem + >>> from sympy.abc import x + + >>> prem(x**2 + 1, 2*x - 4) + 20 + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('prem', 2, exc) + + r = F.prem(G) + + if not opt.polys: + return r.as_expr() + else: + return r + + +@public +def pquo(f, g, *gens, **args): + """ + Compute polynomial pseudo-quotient of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import pquo + >>> from sympy.abc import x + + >>> pquo(x**2 + 1, 2*x - 4) + 2*x + 4 + >>> pquo(x**2 - 1, 2*x - 1) + 2*x + 1 + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('pquo', 2, exc) + + try: + q = F.pquo(G) + except ExactQuotientFailed: + raise ExactQuotientFailed(f, g) + + if not opt.polys: + return q.as_expr() + else: + return q + + +@public +def pexquo(f, g, *gens, **args): + """ + Compute polynomial exact pseudo-quotient of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import pexquo + >>> from sympy.abc import x + + >>> pexquo(x**2 - 1, 2*x - 2) + 2*x + 2 + + >>> pexquo(x**2 + 1, 2*x - 4) + Traceback (most recent call last): + ... + ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1 + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('pexquo', 2, exc) + + q = F.pexquo(G) + + if not opt.polys: + return q.as_expr() + else: + return q + + +@public +def div(f, g, *gens, **args): + """ + Compute polynomial division of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import div, ZZ, QQ + >>> from sympy.abc import x + + >>> div(x**2 + 1, 2*x - 4, domain=ZZ) + (0, x**2 + 1) + >>> div(x**2 + 1, 2*x - 4, domain=QQ) + (x/2 + 1, 5) + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('div', 2, exc) + + q, r = F.div(G, auto=opt.auto) + + if not opt.polys: + return q.as_expr(), r.as_expr() + else: + return q, r + + +@public +def rem(f, g, *gens, **args): + """ + Compute polynomial remainder of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import rem, ZZ, QQ + >>> from sympy.abc import x + + >>> rem(x**2 + 1, 2*x - 4, domain=ZZ) + x**2 + 1 + >>> rem(x**2 + 1, 2*x - 4, domain=QQ) + 5 + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('rem', 2, exc) + + r = F.rem(G, auto=opt.auto) + + if not opt.polys: + return r.as_expr() + else: + return r + + +@public +def quo(f, g, *gens, **args): + """ + Compute polynomial quotient of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import quo + >>> from sympy.abc import x + + >>> quo(x**2 + 1, 2*x - 4) + x/2 + 1 + >>> quo(x**2 - 1, x - 1) + x + 1 + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('quo', 2, exc) + + q = F.quo(G, auto=opt.auto) + + if not opt.polys: + return q.as_expr() + else: + return q + + +@public +def exquo(f, g, *gens, **args): + """ + Compute polynomial exact quotient of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import exquo + >>> from sympy.abc import x + + >>> exquo(x**2 - 1, x - 1) + x + 1 + + >>> exquo(x**2 + 1, 2*x - 4) + Traceback (most recent call last): + ... + ExactQuotientFailed: 2*x - 4 does not divide x**2 + 1 + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('exquo', 2, exc) + + q = F.exquo(G, auto=opt.auto) + + if not opt.polys: + return q.as_expr() + else: + return q + + +@public +def half_gcdex(f, g, *gens, **args): + """ + Half extended Euclidean algorithm of ``f`` and ``g``. + + Returns ``(s, h)`` such that ``h = gcd(f, g)`` and ``s*f = h (mod g)``. + + Examples + ======== + + >>> from sympy import half_gcdex + >>> from sympy.abc import x + + >>> half_gcdex(x**4 - 2*x**3 - 6*x**2 + 12*x + 15, x**3 + x**2 - 4*x - 4) + (3/5 - x/5, x + 1) + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + s, h = domain.half_gcdex(a, b) + except NotImplementedError: + raise ComputationFailed('half_gcdex', 2, exc) + else: + return domain.to_sympy(s), domain.to_sympy(h) + + s, h = F.half_gcdex(G, auto=opt.auto) + + if not opt.polys: + return s.as_expr(), h.as_expr() + else: + return s, h + + +@public +def gcdex(f, g, *gens, **args): + """ + Extended Euclidean algorithm of ``f`` and ``g``. + + Returns ``(s, t, h)`` such that ``h = gcd(f, g)`` and ``s*f + t*g = h``. + + Examples + ======== + + >>> from sympy import gcdex + >>> from sympy.abc import x + + >>> gcdex(x**4 - 2*x**3 - 6*x**2 + 12*x + 15, x**3 + x**2 - 4*x - 4) + (3/5 - x/5, x**2/5 - 6*x/5 + 2, x + 1) + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + s, t, h = domain.gcdex(a, b) + except NotImplementedError: + raise ComputationFailed('gcdex', 2, exc) + else: + return domain.to_sympy(s), domain.to_sympy(t), domain.to_sympy(h) + + s, t, h = F.gcdex(G, auto=opt.auto) + + if not opt.polys: + return s.as_expr(), t.as_expr(), h.as_expr() + else: + return s, t, h + + +@public +def invert(f, g, *gens, **args): + """ + Invert ``f`` modulo ``g`` when possible. + + Examples + ======== + + >>> from sympy import invert, S, mod_inverse + >>> from sympy.abc import x + + >>> invert(x**2 - 1, 2*x - 1) + -4/3 + + >>> invert(x**2 - 1, x - 1) + Traceback (most recent call last): + ... + NotInvertible: zero divisor + + For more efficient inversion of Rationals, + use the :obj:`~.mod_inverse` function: + + >>> mod_inverse(3, 5) + 2 + >>> (S(2)/5).invert(S(7)/3) + 5/2 + + See Also + ======== + + sympy.core.numbers.mod_inverse + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + return domain.to_sympy(domain.invert(a, b)) + except NotImplementedError: + raise ComputationFailed('invert', 2, exc) + + h = F.invert(G, auto=opt.auto) + + if not opt.polys: + return h.as_expr() + else: + return h + + +@public +def subresultants(f, g, *gens, **args): + """ + Compute subresultant PRS of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import subresultants + >>> from sympy.abc import x + + >>> subresultants(x**2 + 1, x**2 - 1) + [x**2 + 1, x**2 - 1, -2] + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('subresultants', 2, exc) + + result = F.subresultants(G) + + if not opt.polys: + return [r.as_expr() for r in result] + else: + return result + + +@public +def resultant(f, g, *gens, includePRS=False, **args): + """ + Compute resultant of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import resultant + >>> from sympy.abc import x + + >>> resultant(x**2 + 1, x**2 - 1) + 4 + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('resultant', 2, exc) + + if includePRS: + result, R = F.resultant(G, includePRS=includePRS) + else: + result = F.resultant(G) + + if not opt.polys: + if includePRS: + return result.as_expr(), [r.as_expr() for r in R] + return result.as_expr() + else: + if includePRS: + return result, R + return result + + +@public +def discriminant(f, *gens, **args): + """ + Compute discriminant of ``f``. + + Examples + ======== + + >>> from sympy import discriminant + >>> from sympy.abc import x + + >>> discriminant(x**2 + 2*x + 3) + -8 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('discriminant', 1, exc) + + result = F.discriminant() + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def cofactors(f, g, *gens, **args): + """ + Compute GCD and cofactors of ``f`` and ``g``. + + Returns polynomials ``(h, cff, cfg)`` such that ``h = gcd(f, g)``, and + ``cff = quo(f, h)`` and ``cfg = quo(g, h)`` are, so called, cofactors + of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import cofactors + >>> from sympy.abc import x + + >>> cofactors(x**2 - 1, x**2 - 3*x + 2) + (x - 1, x + 1, x - 2) + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + h, cff, cfg = domain.cofactors(a, b) + except NotImplementedError: + raise ComputationFailed('cofactors', 2, exc) + else: + return domain.to_sympy(h), domain.to_sympy(cff), domain.to_sympy(cfg) + + h, cff, cfg = F.cofactors(G) + + if not opt.polys: + return h.as_expr(), cff.as_expr(), cfg.as_expr() + else: + return h, cff, cfg + + +@public +def gcd_list(seq, *gens, **args): + """ + Compute GCD of a list of polynomials. + + Examples + ======== + + >>> from sympy import gcd_list + >>> from sympy.abc import x + + >>> gcd_list([x**3 - 1, x**2 - 1, x**2 - 3*x + 2]) + x - 1 + + """ + seq = sympify(seq) + + def try_non_polynomial_gcd(seq): + if not gens and not args: + domain, numbers = construct_domain(seq) + + if not numbers: + return domain.zero + elif domain.is_Numerical: + result, numbers = numbers[0], numbers[1:] + + for number in numbers: + result = domain.gcd(result, number) + + if domain.is_one(result): + break + + return domain.to_sympy(result) + + return None + + result = try_non_polynomial_gcd(seq) + + if result is not None: + return result + + options.allowed_flags(args, ['polys']) + + try: + polys, opt = parallel_poly_from_expr(seq, *gens, **args) + + # gcd for domain Q[irrational] (purely algebraic irrational) + if len(seq) > 1 and all(elt.is_algebraic and elt.is_irrational for elt in seq): + a = seq[-1] + lst = [ (a/elt).ratsimp() for elt in seq[:-1] ] + if all(frc.is_rational for frc in lst): + lc = 1 + for frc in lst: + lc = lcm(lc, frc.as_numer_denom()[0]) + # abs ensures that the gcd is always non-negative + return abs(a/lc) + + except PolificationFailed as exc: + result = try_non_polynomial_gcd(exc.exprs) + + if result is not None: + return result + else: + raise ComputationFailed('gcd_list', len(seq), exc) + + if not polys: + if not opt.polys: + return S.Zero + else: + return Poly(0, opt=opt) + + result, polys = polys[0], polys[1:] + + for poly in polys: + result = result.gcd(poly) + + if result.is_one: + break + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def gcd(f, g=None, *gens, **args): + """ + Compute GCD of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import gcd + >>> from sympy.abc import x + + >>> gcd(x**2 - 1, x**2 - 3*x + 2) + x - 1 + + """ + if hasattr(f, '__iter__'): + if g is not None: + gens = (g,) + gens + + return gcd_list(f, *gens, **args) + elif g is None: + raise TypeError("gcd() takes 2 arguments or a sequence of arguments") + + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + + # gcd for domain Q[irrational] (purely algebraic irrational) + a, b = map(sympify, (f, g)) + if a.is_algebraic and a.is_irrational and b.is_algebraic and b.is_irrational: + frc = (a/b).ratsimp() + if frc.is_rational: + # abs ensures that the returned gcd is always non-negative + return abs(a/frc.as_numer_denom()[0]) + + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + return domain.to_sympy(domain.gcd(a, b)) + except NotImplementedError: + raise ComputationFailed('gcd', 2, exc) + + result = F.gcd(G) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def lcm_list(seq, *gens, **args): + """ + Compute LCM of a list of polynomials. + + Examples + ======== + + >>> from sympy import lcm_list + >>> from sympy.abc import x + + >>> lcm_list([x**3 - 1, x**2 - 1, x**2 - 3*x + 2]) + x**5 - x**4 - 2*x**3 - x**2 + x + 2 + + """ + seq = sympify(seq) + + def try_non_polynomial_lcm(seq) -> Optional[Expr]: + if not gens and not args: + domain, numbers = construct_domain(seq) + + if not numbers: + return domain.to_sympy(domain.one) + elif domain.is_Numerical: + result, numbers = numbers[0], numbers[1:] + + for number in numbers: + result = domain.lcm(result, number) + + return domain.to_sympy(result) + + return None + + result = try_non_polynomial_lcm(seq) + + if result is not None: + return result + + options.allowed_flags(args, ['polys']) + + try: + polys, opt = parallel_poly_from_expr(seq, *gens, **args) + + # lcm for domain Q[irrational] (purely algebraic irrational) + if len(seq) > 1 and all(elt.is_algebraic and elt.is_irrational for elt in seq): + a = seq[-1] + lst = [ (a/elt).ratsimp() for elt in seq[:-1] ] + if all(frc.is_rational for frc in lst): + lc = 1 + for frc in lst: + lc = lcm(lc, frc.as_numer_denom()[1]) + return a*lc + + except PolificationFailed as exc: + result = try_non_polynomial_lcm(exc.exprs) + + if result is not None: + return result + else: + raise ComputationFailed('lcm_list', len(seq), exc) + + if not polys: + if not opt.polys: + return S.One + else: + return Poly(1, opt=opt) + + result, polys = polys[0], polys[1:] + + for poly in polys: + result = result.lcm(poly) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def lcm(f, g=None, *gens, **args): + """ + Compute LCM of ``f`` and ``g``. + + Examples + ======== + + >>> from sympy import lcm + >>> from sympy.abc import x + + >>> lcm(x**2 - 1, x**2 - 3*x + 2) + x**3 - 2*x**2 - x + 2 + + """ + if hasattr(f, '__iter__'): + if g is not None: + gens = (g,) + gens + + return lcm_list(f, *gens, **args) + elif g is None: + raise TypeError("lcm() takes 2 arguments or a sequence of arguments") + + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + + # lcm for domain Q[irrational] (purely algebraic irrational) + a, b = map(sympify, (f, g)) + if a.is_algebraic and a.is_irrational and b.is_algebraic and b.is_irrational: + frc = (a/b).ratsimp() + if frc.is_rational: + return a*frc.as_numer_denom()[1] + + except PolificationFailed as exc: + domain, (a, b) = construct_domain(exc.exprs) + + try: + return domain.to_sympy(domain.lcm(a, b)) + except NotImplementedError: + raise ComputationFailed('lcm', 2, exc) + + result = F.lcm(G) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def terms_gcd(f, *gens, **args): + """ + Remove GCD of terms from ``f``. + + If the ``deep`` flag is True, then the arguments of ``f`` will have + terms_gcd applied to them. + + If a fraction is factored out of ``f`` and ``f`` is an Add, then + an unevaluated Mul will be returned so that automatic simplification + does not redistribute it. The hint ``clear``, when set to False, can be + used to prevent such factoring when all coefficients are not fractions. + + Examples + ======== + + >>> from sympy import terms_gcd, cos + >>> from sympy.abc import x, y + >>> terms_gcd(x**6*y**2 + x**3*y, x, y) + x**3*y*(x**3*y + 1) + + The default action of polys routines is to expand the expression + given to them. terms_gcd follows this behavior: + + >>> terms_gcd((3+3*x)*(x+x*y)) + 3*x*(x*y + x + y + 1) + + If this is not desired then the hint ``expand`` can be set to False. + In this case the expression will be treated as though it were comprised + of one or more terms: + + >>> terms_gcd((3+3*x)*(x+x*y), expand=False) + (3*x + 3)*(x*y + x) + + In order to traverse factors of a Mul or the arguments of other + functions, the ``deep`` hint can be used: + + >>> terms_gcd((3 + 3*x)*(x + x*y), expand=False, deep=True) + 3*x*(x + 1)*(y + 1) + >>> terms_gcd(cos(x + x*y), deep=True) + cos(x*(y + 1)) + + Rationals are factored out by default: + + >>> terms_gcd(x + y/2) + (2*x + y)/2 + + Only the y-term had a coefficient that was a fraction; if one + does not want to factor out the 1/2 in cases like this, the + flag ``clear`` can be set to False: + + >>> terms_gcd(x + y/2, clear=False) + x + y/2 + >>> terms_gcd(x*y/2 + y**2, clear=False) + y*(x/2 + y) + + The ``clear`` flag is ignored if all coefficients are fractions: + + >>> terms_gcd(x/3 + y/2, clear=False) + (2*x + 3*y)/6 + + See Also + ======== + sympy.core.exprtools.gcd_terms, sympy.core.exprtools.factor_terms + + """ + + orig = sympify(f) + + if isinstance(f, Equality): + return Equality(*(terms_gcd(s, *gens, **args) for s in [f.lhs, f.rhs])) + elif isinstance(f, Relational): + raise TypeError("Inequalities cannot be used with terms_gcd. Found: %s" %(f,)) + + if not isinstance(f, Expr) or f.is_Atom: + return orig + + if args.get('deep', False): + new = f.func(*[terms_gcd(a, *gens, **args) for a in f.args]) + args.pop('deep') + args['expand'] = False + return terms_gcd(new, *gens, **args) + + clear = args.pop('clear', True) + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + return exc.expr + + J, f = F.terms_gcd() + + if opt.domain.is_Ring: + if opt.domain.is_Field: + denom, f = f.clear_denoms(convert=True) + + coeff, f = f.primitive() + + if opt.domain.is_Field: + coeff /= denom + else: + coeff = S.One + + term = Mul(*[x**j for x, j in zip(f.gens, J)]) + if equal_valued(coeff, 1): + coeff = S.One + if term == 1: + return orig + + if clear: + return _keep_coeff(coeff, term*f.as_expr()) + # base the clearing on the form of the original expression, not + # the (perhaps) Mul that we have now + coeff, f = _keep_coeff(coeff, f.as_expr(), clear=False).as_coeff_Mul() + return _keep_coeff(coeff, term*f, clear=False) + + +@public +def trunc(f, p, *gens, **args): + """ + Reduce ``f`` modulo a constant ``p``. + + Examples + ======== + + >>> from sympy import trunc + >>> from sympy.abc import x + + >>> trunc(2*x**3 + 3*x**2 + 5*x + 7, 3) + -x**3 - x + 1 + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('trunc', 1, exc) + + result = F.trunc(sympify(p)) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def monic(f, *gens, **args): + """ + Divide all coefficients of ``f`` by ``LC(f)``. + + Examples + ======== + + >>> from sympy import monic + >>> from sympy.abc import x + + >>> monic(3*x**2 + 4*x + 2) + x**2 + 4*x/3 + 2/3 + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('monic', 1, exc) + + result = F.monic(auto=opt.auto) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def content(f, *gens, **args): + """ + Compute GCD of coefficients of ``f``. + + Examples + ======== + + >>> from sympy import content + >>> from sympy.abc import x + + >>> content(6*x**2 + 8*x + 12) + 2 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('content', 1, exc) + + return F.content() + + +@public +def primitive(f, *gens, **args): + """ + Compute content and the primitive form of ``f``. + + Examples + ======== + + >>> from sympy.polys.polytools import primitive + >>> from sympy.abc import x + + >>> primitive(6*x**2 + 8*x + 12) + (2, 3*x**2 + 4*x + 6) + + >>> eq = (2 + 2*x)*x + 2 + + Expansion is performed by default: + + >>> primitive(eq) + (2, x**2 + x + 1) + + Set ``expand`` to False to shut this off. Note that the + extraction will not be recursive; use the as_content_primitive method + for recursive, non-destructive Rational extraction. + + >>> primitive(eq, expand=False) + (1, x*(2*x + 2) + 2) + + >>> eq.as_content_primitive() + (2, x*(x + 1) + 1) + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('primitive', 1, exc) + + cont, result = F.primitive() + if not opt.polys: + return cont, result.as_expr() + else: + return cont, result + + +@public +def compose(f, g, *gens, **args): + """ + Compute functional composition ``f(g)``. + + Examples + ======== + + >>> from sympy import compose + >>> from sympy.abc import x + + >>> compose(x**2 + x, x - 1) + x**2 - x + + """ + options.allowed_flags(args, ['polys']) + + try: + (F, G), opt = parallel_poly_from_expr((f, g), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('compose', 2, exc) + + result = F.compose(G) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def decompose(f, *gens, **args): + """ + Compute functional decomposition of ``f``. + + Examples + ======== + + >>> from sympy import decompose + >>> from sympy.abc import x + + >>> decompose(x**4 + 2*x**3 - x - 1) + [x**2 - x - 1, x**2 + x] + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('decompose', 1, exc) + + result = F.decompose() + + if not opt.polys: + return [r.as_expr() for r in result] + else: + return result + + +@public +def sturm(f, *gens, **args): + """ + Compute Sturm sequence of ``f``. + + Examples + ======== + + >>> from sympy import sturm + >>> from sympy.abc import x + + >>> sturm(x**3 - 2*x**2 + x - 3) + [x**3 - 2*x**2 + x - 3, 3*x**2 - 4*x + 1, 2*x/9 + 25/9, -2079/4] + + """ + options.allowed_flags(args, ['auto', 'polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('sturm', 1, exc) + + result = F.sturm(auto=opt.auto) + + if not opt.polys: + return [r.as_expr() for r in result] + else: + return result + + +@public +def gff_list(f, *gens, **args): + """ + Compute a list of greatest factorial factors of ``f``. + + Note that the input to ff() and rf() should be Poly instances to use the + definitions here. + + Examples + ======== + + >>> from sympy import gff_list, ff, Poly + >>> from sympy.abc import x + + >>> f = Poly(x**5 + 2*x**4 - x**3 - 2*x**2, x) + + >>> gff_list(f) + [(Poly(x, x, domain='ZZ'), 1), (Poly(x + 2, x, domain='ZZ'), 4)] + + >>> (ff(Poly(x), 1)*ff(Poly(x + 2), 4)) == f + True + + >>> f = Poly(x**12 + 6*x**11 - 11*x**10 - 56*x**9 + 220*x**8 + 208*x**7 - \ + 1401*x**6 + 1090*x**5 + 2715*x**4 - 6720*x**3 - 1092*x**2 + 5040*x, x) + + >>> gff_list(f) + [(Poly(x**3 + 7, x, domain='ZZ'), 2), (Poly(x**2 + 5*x, x, domain='ZZ'), 3)] + + >>> ff(Poly(x**3 + 7, x), 2)*ff(Poly(x**2 + 5*x, x), 3) == f + True + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('gff_list', 1, exc) + + factors = F.gff_list() + + if not opt.polys: + return [(g.as_expr(), k) for g, k in factors] + else: + return factors + + +@public +def gff(f, *gens, **args): + """Compute greatest factorial factorization of ``f``. """ + raise NotImplementedError('symbolic falling factorial') + + +@public +def sqf_norm(f, *gens, **args): + """ + Compute square-free norm of ``f``. + + Returns ``s``, ``f``, ``r``, such that ``g(x) = f(x-sa)`` and + ``r(x) = Norm(g(x))`` is a square-free polynomial over ``K``, + where ``a`` is the algebraic extension of the ground domain. + + Examples + ======== + + >>> from sympy import sqf_norm, sqrt + >>> from sympy.abc import x + + >>> sqf_norm(x**2 + 1, extension=[sqrt(3)]) + (1, x**2 - 2*sqrt(3)*x + 4, x**4 - 4*x**2 + 16) + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('sqf_norm', 1, exc) + + s, g, r = F.sqf_norm() + + if not opt.polys: + return Integer(s), g.as_expr(), r.as_expr() + else: + return Integer(s), g, r + + +@public +def sqf_part(f, *gens, **args): + """ + Compute square-free part of ``f``. + + Examples + ======== + + >>> from sympy import sqf_part + >>> from sympy.abc import x + + >>> sqf_part(x**3 - 3*x - 2) + x**2 - x - 2 + + """ + options.allowed_flags(args, ['polys']) + + try: + F, opt = poly_from_expr(f, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('sqf_part', 1, exc) + + result = F.sqf_part() + + if not opt.polys: + return result.as_expr() + else: + return result + + +def _sorted_factors(factors, method): + """Sort a list of ``(expr, exp)`` pairs. """ + if method == 'sqf': + def key(obj): + poly, exp = obj + rep = poly.rep.rep + return (exp, len(rep), len(poly.gens), str(poly.domain), rep) + else: + def key(obj): + poly, exp = obj + rep = poly.rep.rep + return (len(rep), len(poly.gens), exp, str(poly.domain), rep) + + return sorted(factors, key=key) + + +def _factors_product(factors): + """Multiply a list of ``(expr, exp)`` pairs. """ + return Mul(*[f.as_expr()**k for f, k in factors]) + + +def _symbolic_factor_list(expr, opt, method): + """Helper function for :func:`_symbolic_factor`. """ + coeff, factors = S.One, [] + + args = [i._eval_factor() if hasattr(i, '_eval_factor') else i + for i in Mul.make_args(expr)] + for arg in args: + if arg.is_Number or (isinstance(arg, Expr) and pure_complex(arg)): + coeff *= arg + continue + elif arg.is_Pow and arg.base != S.Exp1: + base, exp = arg.args + if base.is_Number and exp.is_Number: + coeff *= arg + continue + if base.is_Number: + factors.append((base, exp)) + continue + else: + base, exp = arg, S.One + + try: + poly, _ = _poly_from_expr(base, opt) + except PolificationFailed as exc: + factors.append((exc.expr, exp)) + else: + func = getattr(poly, method + '_list') + + _coeff, _factors = func() + if _coeff is not S.One: + if exp.is_Integer: + coeff *= _coeff**exp + elif _coeff.is_positive: + factors.append((_coeff, exp)) + else: + _factors.append((_coeff, S.One)) + + if exp is S.One: + factors.extend(_factors) + elif exp.is_integer: + factors.extend([(f, k*exp) for f, k in _factors]) + else: + other = [] + + for f, k in _factors: + if f.as_expr().is_positive: + factors.append((f, k*exp)) + else: + other.append((f, k)) + + factors.append((_factors_product(other), exp)) + if method == 'sqf': + factors = [(reduce(mul, (f for f, _ in factors if _ == k)), k) + for k in {i for _, i in factors}] + + return coeff, factors + + +def _symbolic_factor(expr, opt, method): + """Helper function for :func:`_factor`. """ + if isinstance(expr, Expr): + if hasattr(expr,'_eval_factor'): + return expr._eval_factor() + coeff, factors = _symbolic_factor_list(together(expr, fraction=opt['fraction']), opt, method) + return _keep_coeff(coeff, _factors_product(factors)) + elif hasattr(expr, 'args'): + return expr.func(*[_symbolic_factor(arg, opt, method) for arg in expr.args]) + elif hasattr(expr, '__iter__'): + return expr.__class__([_symbolic_factor(arg, opt, method) for arg in expr]) + else: + return expr + + +def _generic_factor_list(expr, gens, args, method): + """Helper function for :func:`sqf_list` and :func:`factor_list`. """ + options.allowed_flags(args, ['frac', 'polys']) + opt = options.build_options(gens, args) + + expr = sympify(expr) + + if isinstance(expr, (Expr, Poly)): + if isinstance(expr, Poly): + numer, denom = expr, 1 + else: + numer, denom = together(expr).as_numer_denom() + + cp, fp = _symbolic_factor_list(numer, opt, method) + cq, fq = _symbolic_factor_list(denom, opt, method) + + if fq and not opt.frac: + raise PolynomialError("a polynomial expected, got %s" % expr) + + _opt = opt.clone({"expand": True}) + + for factors in (fp, fq): + for i, (f, k) in enumerate(factors): + if not f.is_Poly: + f, _ = _poly_from_expr(f, _opt) + factors[i] = (f, k) + + fp = _sorted_factors(fp, method) + fq = _sorted_factors(fq, method) + + if not opt.polys: + fp = [(f.as_expr(), k) for f, k in fp] + fq = [(f.as_expr(), k) for f, k in fq] + + coeff = cp/cq + + if not opt.frac: + return coeff, fp + else: + return coeff, fp, fq + else: + raise PolynomialError("a polynomial expected, got %s" % expr) + + +def _generic_factor(expr, gens, args, method): + """Helper function for :func:`sqf` and :func:`factor`. """ + fraction = args.pop('fraction', True) + options.allowed_flags(args, []) + opt = options.build_options(gens, args) + opt['fraction'] = fraction + return _symbolic_factor(sympify(expr), opt, method) + + +def to_rational_coeffs(f): + """ + try to transform a polynomial to have rational coefficients + + try to find a transformation ``x = alpha*y`` + + ``f(x) = lc*alpha**n * g(y)`` where ``g`` is a polynomial with + rational coefficients, ``lc`` the leading coefficient. + + If this fails, try ``x = y + beta`` + ``f(x) = g(y)`` + + Returns ``None`` if ``g`` not found; + ``(lc, alpha, None, g)`` in case of rescaling + ``(None, None, beta, g)`` in case of translation + + Notes + ===== + + Currently it transforms only polynomials without roots larger than 2. + + Examples + ======== + + >>> from sympy import sqrt, Poly, simplify + >>> from sympy.polys.polytools import to_rational_coeffs + >>> from sympy.abc import x + >>> p = Poly(((x**2-1)*(x-2)).subs({x:x*(1 + sqrt(2))}), x, domain='EX') + >>> lc, r, _, g = to_rational_coeffs(p) + >>> lc, r + (7 + 5*sqrt(2), 2 - 2*sqrt(2)) + >>> g + Poly(x**3 + x**2 - 1/4*x - 1/4, x, domain='QQ') + >>> r1 = simplify(1/r) + >>> Poly(lc*r**3*(g.as_expr()).subs({x:x*r1}), x, domain='EX') == p + True + + """ + from sympy.simplify.simplify import simplify + + def _try_rescale(f, f1=None): + """ + try rescaling ``x -> alpha*x`` to convert f to a polynomial + with rational coefficients. + Returns ``alpha, f``; if the rescaling is successful, + ``alpha`` is the rescaling factor, and ``f`` is the rescaled + polynomial; else ``alpha`` is ``None``. + """ + if not len(f.gens) == 1 or not (f.gens[0]).is_Atom: + return None, f + n = f.degree() + lc = f.LC() + f1 = f1 or f1.monic() + coeffs = f1.all_coeffs()[1:] + coeffs = [simplify(coeffx) for coeffx in coeffs] + if len(coeffs) > 1 and coeffs[-2]: + rescale1_x = simplify(coeffs[-2]/coeffs[-1]) + coeffs1 = [] + for i in range(len(coeffs)): + coeffx = simplify(coeffs[i]*rescale1_x**(i + 1)) + if not coeffx.is_rational: + break + coeffs1.append(coeffx) + else: + rescale_x = simplify(1/rescale1_x) + x = f.gens[0] + v = [x**n] + for i in range(1, n + 1): + v.append(coeffs1[i - 1]*x**(n - i)) + f = Add(*v) + f = Poly(f) + return lc, rescale_x, f + return None + + def _try_translate(f, f1=None): + """ + try translating ``x -> x + alpha`` to convert f to a polynomial + with rational coefficients. + Returns ``alpha, f``; if the translating is successful, + ``alpha`` is the translating factor, and ``f`` is the shifted + polynomial; else ``alpha`` is ``None``. + """ + if not len(f.gens) == 1 or not (f.gens[0]).is_Atom: + return None, f + n = f.degree() + f1 = f1 or f1.monic() + coeffs = f1.all_coeffs()[1:] + c = simplify(coeffs[0]) + if c.is_Add and not c.is_rational: + rat, nonrat = sift(c.args, + lambda z: z.is_rational is True, binary=True) + alpha = -c.func(*nonrat)/n + f2 = f1.shift(alpha) + return alpha, f2 + return None + + def _has_square_roots(p): + """ + Return True if ``f`` is a sum with square roots but no other root + """ + coeffs = p.coeffs() + has_sq = False + for y in coeffs: + for x in Add.make_args(y): + f = Factors(x).factors + r = [wx.q for b, wx in f.items() if + b.is_number and wx.is_Rational and wx.q >= 2] + if not r: + continue + if min(r) == 2: + has_sq = True + if max(r) > 2: + return False + return has_sq + + if f.get_domain().is_EX and _has_square_roots(f): + f1 = f.monic() + r = _try_rescale(f, f1) + if r: + return r[0], r[1], None, r[2] + else: + r = _try_translate(f, f1) + if r: + return None, None, r[0], r[1] + return None + + +def _torational_factor_list(p, x): + """ + helper function to factor polynomial using to_rational_coeffs + + Examples + ======== + + >>> from sympy.polys.polytools import _torational_factor_list + >>> from sympy.abc import x + >>> from sympy import sqrt, expand, Mul + >>> p = expand(((x**2-1)*(x-2)).subs({x:x*(1 + sqrt(2))})) + >>> factors = _torational_factor_list(p, x); factors + (-2, [(-x*(1 + sqrt(2))/2 + 1, 1), (-x*(1 + sqrt(2)) - 1, 1), (-x*(1 + sqrt(2)) + 1, 1)]) + >>> expand(factors[0]*Mul(*[z[0] for z in factors[1]])) == p + True + >>> p = expand(((x**2-1)*(x-2)).subs({x:x + sqrt(2)})) + >>> factors = _torational_factor_list(p, x); factors + (1, [(x - 2 + sqrt(2), 1), (x - 1 + sqrt(2), 1), (x + 1 + sqrt(2), 1)]) + >>> expand(factors[0]*Mul(*[z[0] for z in factors[1]])) == p + True + + """ + from sympy.simplify.simplify import simplify + p1 = Poly(p, x, domain='EX') + n = p1.degree() + res = to_rational_coeffs(p1) + if not res: + return None + lc, r, t, g = res + factors = factor_list(g.as_expr()) + if lc: + c = simplify(factors[0]*lc*r**n) + r1 = simplify(1/r) + a = [] + for z in factors[1:][0]: + a.append((simplify(z[0].subs({x: x*r1})), z[1])) + else: + c = factors[0] + a = [] + for z in factors[1:][0]: + a.append((z[0].subs({x: x - t}), z[1])) + return (c, a) + + +@public +def sqf_list(f, *gens, **args): + """ + Compute a list of square-free factors of ``f``. + + Examples + ======== + + >>> from sympy import sqf_list + >>> from sympy.abc import x + + >>> sqf_list(2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16) + (2, [(x + 1, 2), (x + 2, 3)]) + + """ + return _generic_factor_list(f, gens, args, method='sqf') + + +@public +def sqf(f, *gens, **args): + """ + Compute square-free factorization of ``f``. + + Examples + ======== + + >>> from sympy import sqf + >>> from sympy.abc import x + + >>> sqf(2*x**5 + 16*x**4 + 50*x**3 + 76*x**2 + 56*x + 16) + 2*(x + 1)**2*(x + 2)**3 + + """ + return _generic_factor(f, gens, args, method='sqf') + + +@public +def factor_list(f, *gens, **args): + """ + Compute a list of irreducible factors of ``f``. + + Examples + ======== + + >>> from sympy import factor_list + >>> from sympy.abc import x, y + + >>> factor_list(2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y) + (2, [(x + y, 1), (x**2 + 1, 2)]) + + """ + return _generic_factor_list(f, gens, args, method='factor') + + +@public +def factor(f, *gens, deep=False, **args): + """ + Compute the factorization of expression, ``f``, into irreducibles. (To + factor an integer into primes, use ``factorint``.) + + There two modes implemented: symbolic and formal. If ``f`` is not an + instance of :class:`Poly` and generators are not specified, then the + former mode is used. Otherwise, the formal mode is used. + + In symbolic mode, :func:`factor` will traverse the expression tree and + factor its components without any prior expansion, unless an instance + of :class:`~.Add` is encountered (in this case formal factorization is + used). This way :func:`factor` can handle large or symbolic exponents. + + By default, the factorization is computed over the rationals. To factor + over other domain, e.g. an algebraic or finite field, use appropriate + options: ``extension``, ``modulus`` or ``domain``. + + Examples + ======== + + >>> from sympy import factor, sqrt, exp + >>> from sympy.abc import x, y + + >>> factor(2*x**5 + 2*x**4*y + 4*x**3 + 4*x**2*y + 2*x + 2*y) + 2*(x + y)*(x**2 + 1)**2 + + >>> factor(x**2 + 1) + x**2 + 1 + >>> factor(x**2 + 1, modulus=2) + (x + 1)**2 + >>> factor(x**2 + 1, gaussian=True) + (x - I)*(x + I) + + >>> factor(x**2 - 2, extension=sqrt(2)) + (x - sqrt(2))*(x + sqrt(2)) + + >>> factor((x**2 - 1)/(x**2 + 4*x + 4)) + (x - 1)*(x + 1)/(x + 2)**2 + >>> factor((x**2 + 4*x + 4)**10000000*(x**2 + 1)) + (x + 2)**20000000*(x**2 + 1) + + By default, factor deals with an expression as a whole: + + >>> eq = 2**(x**2 + 2*x + 1) + >>> factor(eq) + 2**(x**2 + 2*x + 1) + + If the ``deep`` flag is True then subexpressions will + be factored: + + >>> factor(eq, deep=True) + 2**((x + 1)**2) + + If the ``fraction`` flag is False then rational expressions + will not be combined. By default it is True. + + >>> factor(5*x + 3*exp(2 - 7*x), deep=True) + (5*x*exp(7*x) + 3*exp(2))*exp(-7*x) + >>> factor(5*x + 3*exp(2 - 7*x), deep=True, fraction=False) + 5*x + 3*exp(2)*exp(-7*x) + + See Also + ======== + sympy.ntheory.factor_.factorint + + """ + f = sympify(f) + if deep: + def _try_factor(expr): + """ + Factor, but avoid changing the expression when unable to. + """ + fac = factor(expr, *gens, **args) + if fac.is_Mul or fac.is_Pow: + return fac + return expr + + f = bottom_up(f, _try_factor) + # clean up any subexpressions that may have been expanded + # while factoring out a larger expression + partials = {} + muladd = f.atoms(Mul, Add) + for p in muladd: + fac = factor(p, *gens, **args) + if (fac.is_Mul or fac.is_Pow) and fac != p: + partials[p] = fac + return f.xreplace(partials) + + try: + return _generic_factor(f, gens, args, method='factor') + except PolynomialError as msg: + if not f.is_commutative: + return factor_nc(f) + else: + raise PolynomialError(msg) + + +@public +def intervals(F, all=False, eps=None, inf=None, sup=None, strict=False, fast=False, sqf=False): + """ + Compute isolating intervals for roots of ``f``. + + Examples + ======== + + >>> from sympy import intervals + >>> from sympy.abc import x + + >>> intervals(x**2 - 3) + [((-2, -1), 1), ((1, 2), 1)] + >>> intervals(x**2 - 3, eps=1e-2) + [((-26/15, -19/11), 1), ((19/11, 26/15), 1)] + + """ + if not hasattr(F, '__iter__'): + try: + F = Poly(F) + except GeneratorsNeeded: + return [] + + return F.intervals(all=all, eps=eps, inf=inf, sup=sup, fast=fast, sqf=sqf) + else: + polys, opt = parallel_poly_from_expr(F, domain='QQ') + + if len(opt.gens) > 1: + raise MultivariatePolynomialError + + for i, poly in enumerate(polys): + polys[i] = poly.rep.rep + + if eps is not None: + eps = opt.domain.convert(eps) + + if eps <= 0: + raise ValueError("'eps' must be a positive rational") + + if inf is not None: + inf = opt.domain.convert(inf) + if sup is not None: + sup = opt.domain.convert(sup) + + intervals = dup_isolate_real_roots_list(polys, opt.domain, + eps=eps, inf=inf, sup=sup, strict=strict, fast=fast) + + result = [] + + for (s, t), indices in intervals: + s, t = opt.domain.to_sympy(s), opt.domain.to_sympy(t) + result.append(((s, t), indices)) + + return result + + +@public +def refine_root(f, s, t, eps=None, steps=None, fast=False, check_sqf=False): + """ + Refine an isolating interval of a root to the given precision. + + Examples + ======== + + >>> from sympy import refine_root + >>> from sympy.abc import x + + >>> refine_root(x**2 - 3, 1, 2, eps=1e-2) + (19/11, 26/15) + + """ + try: + F = Poly(f) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except GeneratorsNeeded: + raise PolynomialError( + "Cannot refine a root of %s, not a polynomial" % f) + + return F.refine_root(s, t, eps=eps, steps=steps, fast=fast, check_sqf=check_sqf) + + +@public +def count_roots(f, inf=None, sup=None): + """ + Return the number of roots of ``f`` in ``[inf, sup]`` interval. + + If one of ``inf`` or ``sup`` is complex, it will return the number of roots + in the complex rectangle with corners at ``inf`` and ``sup``. + + Examples + ======== + + >>> from sympy import count_roots, I + >>> from sympy.abc import x + + >>> count_roots(x**4 - 4, -3, 3) + 2 + >>> count_roots(x**4 - 4, 0, 1 + 3*I) + 1 + + """ + try: + F = Poly(f, greedy=False) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except GeneratorsNeeded: + raise PolynomialError("Cannot count roots of %s, not a polynomial" % f) + + return F.count_roots(inf=inf, sup=sup) + + +@public +def real_roots(f, multiple=True): + """ + Return a list of real roots with multiplicities of ``f``. + + Examples + ======== + + >>> from sympy import real_roots + >>> from sympy.abc import x + + >>> real_roots(2*x**3 - 7*x**2 + 4*x + 4) + [-1/2, 2, 2] + """ + try: + F = Poly(f, greedy=False) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except GeneratorsNeeded: + raise PolynomialError( + "Cannot compute real roots of %s, not a polynomial" % f) + + return F.real_roots(multiple=multiple) + + +@public +def nroots(f, n=15, maxsteps=50, cleanup=True): + """ + Compute numerical approximations of roots of ``f``. + + Examples + ======== + + >>> from sympy import nroots + >>> from sympy.abc import x + + >>> nroots(x**2 - 3, n=15) + [-1.73205080756888, 1.73205080756888] + >>> nroots(x**2 - 3, n=30) + [-1.73205080756887729352744634151, 1.73205080756887729352744634151] + + """ + try: + F = Poly(f, greedy=False) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except GeneratorsNeeded: + raise PolynomialError( + "Cannot compute numerical roots of %s, not a polynomial" % f) + + return F.nroots(n=n, maxsteps=maxsteps, cleanup=cleanup) + + +@public +def ground_roots(f, *gens, **args): + """ + Compute roots of ``f`` by factorization in the ground domain. + + Examples + ======== + + >>> from sympy import ground_roots + >>> from sympy.abc import x + + >>> ground_roots(x**6 - 4*x**4 + 4*x**3 - x**2) + {0: 2, 1: 2} + + """ + options.allowed_flags(args, []) + + try: + F, opt = poly_from_expr(f, *gens, **args) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except PolificationFailed as exc: + raise ComputationFailed('ground_roots', 1, exc) + + return F.ground_roots() + + +@public +def nth_power_roots_poly(f, n, *gens, **args): + """ + Construct a polynomial with n-th powers of roots of ``f``. + + Examples + ======== + + >>> from sympy import nth_power_roots_poly, factor, roots + >>> from sympy.abc import x + + >>> f = x**4 - x**2 + 1 + >>> g = factor(nth_power_roots_poly(f, 2)) + + >>> g + (x**2 - x + 1)**2 + + >>> R_f = [ (r**2).expand() for r in roots(f) ] + >>> R_g = roots(g).keys() + + >>> set(R_f) == set(R_g) + True + + """ + options.allowed_flags(args, []) + + try: + F, opt = poly_from_expr(f, *gens, **args) + if not isinstance(f, Poly) and not F.gen.is_Symbol: + # root of sin(x) + 1 is -1 but when someone + # passes an Expr instead of Poly they may not expect + # that the generator will be sin(x), not x + raise PolynomialError("generator must be a Symbol") + except PolificationFailed as exc: + raise ComputationFailed('nth_power_roots_poly', 1, exc) + + result = F.nth_power_roots_poly(n) + + if not opt.polys: + return result.as_expr() + else: + return result + + +@public +def cancel(f, *gens, _signsimp=True, **args): + """ + Cancel common factors in a rational function ``f``. + + Examples + ======== + + >>> from sympy import cancel, sqrt, Symbol, together + >>> from sympy.abc import x + >>> A = Symbol('A', commutative=False) + + >>> cancel((2*x**2 - 2)/(x**2 - 2*x + 1)) + (2*x + 2)/(x - 1) + >>> cancel((sqrt(3) + sqrt(15)*A)/(sqrt(2) + sqrt(10)*A)) + sqrt(6)/2 + + Note: due to automatic distribution of Rationals, a sum divided by an integer + will appear as a sum. To recover a rational form use `together` on the result: + + >>> cancel(x/2 + 1) + x/2 + 1 + >>> together(_) + (x + 2)/2 + """ + from sympy.simplify.simplify import signsimp + from sympy.polys.rings import sring + options.allowed_flags(args, ['polys']) + + f = sympify(f) + if _signsimp: + f = signsimp(f) + opt = {} + if 'polys' in args: + opt['polys'] = args['polys'] + + if not isinstance(f, (tuple, Tuple)): + if f.is_Number or isinstance(f, Relational) or not isinstance(f, Expr): + return f + f = factor_terms(f, radical=True) + p, q = f.as_numer_denom() + + elif len(f) == 2: + p, q = f + if isinstance(p, Poly) and isinstance(q, Poly): + opt['gens'] = p.gens + opt['domain'] = p.domain + opt['polys'] = opt.get('polys', True) + p, q = p.as_expr(), q.as_expr() + elif isinstance(f, Tuple): + return factor_terms(f) + else: + raise ValueError('unexpected argument: %s' % f) + + from sympy.functions.elementary.piecewise import Piecewise + try: + if f.has(Piecewise): + raise PolynomialError() + R, (F, G) = sring((p, q), *gens, **args) + if not R.ngens: + if not isinstance(f, (tuple, Tuple)): + return f.expand() + else: + return S.One, p, q + except PolynomialError as msg: + if f.is_commutative and not f.has(Piecewise): + raise PolynomialError(msg) + # Handling of noncommutative and/or piecewise expressions + if f.is_Add or f.is_Mul: + c, nc = sift(f.args, lambda x: + x.is_commutative is True and not x.has(Piecewise), + binary=True) + nc = [cancel(i) for i in nc] + return f.func(cancel(f.func(*c)), *nc) + else: + reps = [] + pot = preorder_traversal(f) + next(pot) + for e in pot: + # XXX: This should really skip anything that's not Expr. + if isinstance(e, (tuple, Tuple, BooleanAtom)): + continue + try: + reps.append((e, cancel(e))) + pot.skip() # this was handled successfully + except NotImplementedError: + pass + return f.xreplace(dict(reps)) + + c, (P, Q) = 1, F.cancel(G) + if opt.get('polys', False) and 'gens' not in opt: + opt['gens'] = R.symbols + + if not isinstance(f, (tuple, Tuple)): + return c*(P.as_expr()/Q.as_expr()) + else: + P, Q = P.as_expr(), Q.as_expr() + if not opt.get('polys', False): + return c, P, Q + else: + return c, Poly(P, *gens, **opt), Poly(Q, *gens, **opt) + + +@public +def reduced(f, G, *gens, **args): + """ + Reduces a polynomial ``f`` modulo a set of polynomials ``G``. + + Given a polynomial ``f`` and a set of polynomials ``G = (g_1, ..., g_n)``, + computes a set of quotients ``q = (q_1, ..., q_n)`` and the remainder ``r`` + such that ``f = q_1*g_1 + ... + q_n*g_n + r``, where ``r`` vanishes or ``r`` + is a completely reduced polynomial with respect to ``G``. + + Examples + ======== + + >>> from sympy import reduced + >>> from sympy.abc import x, y + + >>> reduced(2*x**4 + y**2 - x**2 + y**3, [x**3 - x, y**3 - y]) + ([2*x, 1], x**2 + y**2 + y) + + """ + options.allowed_flags(args, ['polys', 'auto']) + + try: + polys, opt = parallel_poly_from_expr([f] + list(G), *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('reduced', 0, exc) + + domain = opt.domain + retract = False + + if opt.auto and domain.is_Ring and not domain.is_Field: + opt = opt.clone({"domain": domain.get_field()}) + retract = True + + from sympy.polys.rings import xring + _ring, _ = xring(opt.gens, opt.domain, opt.order) + + for i, poly in enumerate(polys): + poly = poly.set_domain(opt.domain).rep.to_dict() + polys[i] = _ring.from_dict(poly) + + Q, r = polys[0].div(polys[1:]) + + Q = [Poly._from_dict(dict(q), opt) for q in Q] + r = Poly._from_dict(dict(r), opt) + + if retract: + try: + _Q, _r = [q.to_ring() for q in Q], r.to_ring() + except CoercionFailed: + pass + else: + Q, r = _Q, _r + + if not opt.polys: + return [q.as_expr() for q in Q], r.as_expr() + else: + return Q, r + + +@public +def groebner(F, *gens, **args): + """ + Computes the reduced Groebner basis for a set of polynomials. + + Use the ``order`` argument to set the monomial ordering that will be + used to compute the basis. Allowed orders are ``lex``, ``grlex`` and + ``grevlex``. If no order is specified, it defaults to ``lex``. + + For more information on Groebner bases, see the references and the docstring + of :func:`~.solve_poly_system`. + + Examples + ======== + + Example taken from [1]. + + >>> from sympy import groebner + >>> from sympy.abc import x, y + + >>> F = [x*y - 2*y, 2*y**2 - x**2] + + >>> groebner(F, x, y, order='lex') + GroebnerBasis([x**2 - 2*y**2, x*y - 2*y, y**3 - 2*y], x, y, + domain='ZZ', order='lex') + >>> groebner(F, x, y, order='grlex') + GroebnerBasis([y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y], x, y, + domain='ZZ', order='grlex') + >>> groebner(F, x, y, order='grevlex') + GroebnerBasis([y**3 - 2*y, x**2 - 2*y**2, x*y - 2*y], x, y, + domain='ZZ', order='grevlex') + + By default, an improved implementation of the Buchberger algorithm is + used. Optionally, an implementation of the F5B algorithm can be used. The + algorithm can be set using the ``method`` flag or with the + :func:`sympy.polys.polyconfig.setup` function. + + >>> F = [x**2 - x - 1, (2*x - 1) * y - (x**10 - (1 - x)**10)] + + >>> groebner(F, x, y, method='buchberger') + GroebnerBasis([x**2 - x - 1, y - 55], x, y, domain='ZZ', order='lex') + >>> groebner(F, x, y, method='f5b') + GroebnerBasis([x**2 - x - 1, y - 55], x, y, domain='ZZ', order='lex') + + References + ========== + + 1. [Buchberger01]_ + 2. [Cox97]_ + + """ + return GroebnerBasis(F, *gens, **args) + + +@public +def is_zero_dimensional(F, *gens, **args): + """ + Checks if the ideal generated by a Groebner basis is zero-dimensional. + + The algorithm checks if the set of monomials not divisible by the + leading monomial of any element of ``F`` is bounded. + + References + ========== + + David A. Cox, John B. Little, Donal O'Shea. Ideals, Varieties and + Algorithms, 3rd edition, p. 230 + + """ + return GroebnerBasis(F, *gens, **args).is_zero_dimensional + + +@public +class GroebnerBasis(Basic): + """Represents a reduced Groebner basis. """ + + def __new__(cls, F, *gens, **args): + """Compute a reduced Groebner basis for a system of polynomials. """ + options.allowed_flags(args, ['polys', 'method']) + + try: + polys, opt = parallel_poly_from_expr(F, *gens, **args) + except PolificationFailed as exc: + raise ComputationFailed('groebner', len(F), exc) + + from sympy.polys.rings import PolyRing + ring = PolyRing(opt.gens, opt.domain, opt.order) + + polys = [ring.from_dict(poly.rep.to_dict()) for poly in polys if poly] + + G = _groebner(polys, ring, method=opt.method) + G = [Poly._from_dict(g, opt) for g in G] + + return cls._new(G, opt) + + @classmethod + def _new(cls, basis, options): + obj = Basic.__new__(cls) + + obj._basis = tuple(basis) + obj._options = options + + return obj + + @property + def args(self): + basis = (p.as_expr() for p in self._basis) + return (Tuple(*basis), Tuple(*self._options.gens)) + + @property + def exprs(self): + return [poly.as_expr() for poly in self._basis] + + @property + def polys(self): + return list(self._basis) + + @property + def gens(self): + return self._options.gens + + @property + def domain(self): + return self._options.domain + + @property + def order(self): + return self._options.order + + def __len__(self): + return len(self._basis) + + def __iter__(self): + if self._options.polys: + return iter(self.polys) + else: + return iter(self.exprs) + + def __getitem__(self, item): + if self._options.polys: + basis = self.polys + else: + basis = self.exprs + + return basis[item] + + def __hash__(self): + return hash((self._basis, tuple(self._options.items()))) + + def __eq__(self, other): + if isinstance(other, self.__class__): + return self._basis == other._basis and self._options == other._options + elif iterable(other): + return self.polys == list(other) or self.exprs == list(other) + else: + return False + + def __ne__(self, other): + return not self == other + + @property + def is_zero_dimensional(self): + """ + Checks if the ideal generated by a Groebner basis is zero-dimensional. + + The algorithm checks if the set of monomials not divisible by the + leading monomial of any element of ``F`` is bounded. + + References + ========== + + David A. Cox, John B. Little, Donal O'Shea. Ideals, Varieties and + Algorithms, 3rd edition, p. 230 + + """ + def single_var(monomial): + return sum(map(bool, monomial)) == 1 + + exponents = Monomial([0]*len(self.gens)) + order = self._options.order + + for poly in self.polys: + monomial = poly.LM(order=order) + + if single_var(monomial): + exponents *= monomial + + # If any element of the exponents vector is zero, then there's + # a variable for which there's no degree bound and the ideal + # generated by this Groebner basis isn't zero-dimensional. + return all(exponents) + + def fglm(self, order): + """ + Convert a Groebner basis from one ordering to another. + + The FGLM algorithm converts reduced Groebner bases of zero-dimensional + ideals from one ordering to another. This method is often used when it + is infeasible to compute a Groebner basis with respect to a particular + ordering directly. + + Examples + ======== + + >>> from sympy.abc import x, y + >>> from sympy import groebner + + >>> F = [x**2 - 3*y - x + 1, y**2 - 2*x + y - 1] + >>> G = groebner(F, x, y, order='grlex') + + >>> list(G.fglm('lex')) + [2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7] + >>> list(groebner(F, x, y, order='lex')) + [2*x - y**2 - y + 1, y**4 + 2*y**3 - 3*y**2 - 16*y + 7] + + References + ========== + + .. [1] J.C. Faugere, P. Gianni, D. Lazard, T. Mora (1994). Efficient + Computation of Zero-dimensional Groebner Bases by Change of + Ordering + + """ + opt = self._options + + src_order = opt.order + dst_order = monomial_key(order) + + if src_order == dst_order: + return self + + if not self.is_zero_dimensional: + raise NotImplementedError("Cannot convert Groebner bases of ideals with positive dimension") + + polys = list(self._basis) + domain = opt.domain + + opt = opt.clone({ + "domain": domain.get_field(), + "order": dst_order, + }) + + from sympy.polys.rings import xring + _ring, _ = xring(opt.gens, opt.domain, src_order) + + for i, poly in enumerate(polys): + poly = poly.set_domain(opt.domain).rep.to_dict() + polys[i] = _ring.from_dict(poly) + + G = matrix_fglm(polys, _ring, dst_order) + G = [Poly._from_dict(dict(g), opt) for g in G] + + if not domain.is_Field: + G = [g.clear_denoms(convert=True)[1] for g in G] + opt.domain = domain + + return self._new(G, opt) + + def reduce(self, expr, auto=True): + """ + Reduces a polynomial modulo a Groebner basis. + + Given a polynomial ``f`` and a set of polynomials ``G = (g_1, ..., g_n)``, + computes a set of quotients ``q = (q_1, ..., q_n)`` and the remainder ``r`` + such that ``f = q_1*f_1 + ... + q_n*f_n + r``, where ``r`` vanishes or ``r`` + is a completely reduced polynomial with respect to ``G``. + + Examples + ======== + + >>> from sympy import groebner, expand + >>> from sympy.abc import x, y + + >>> f = 2*x**4 - x**2 + y**3 + y**2 + >>> G = groebner([x**3 - x, y**3 - y]) + + >>> G.reduce(f) + ([2*x, 1], x**2 + y**2 + y) + >>> Q, r = _ + + >>> expand(sum(q*g for q, g in zip(Q, G)) + r) + 2*x**4 - x**2 + y**3 + y**2 + >>> _ == f + True + + """ + poly = Poly._from_expr(expr, self._options) + polys = [poly] + list(self._basis) + + opt = self._options + domain = opt.domain + + retract = False + + if auto and domain.is_Ring and not domain.is_Field: + opt = opt.clone({"domain": domain.get_field()}) + retract = True + + from sympy.polys.rings import xring + _ring, _ = xring(opt.gens, opt.domain, opt.order) + + for i, poly in enumerate(polys): + poly = poly.set_domain(opt.domain).rep.to_dict() + polys[i] = _ring.from_dict(poly) + + Q, r = polys[0].div(polys[1:]) + + Q = [Poly._from_dict(dict(q), opt) for q in Q] + r = Poly._from_dict(dict(r), opt) + + if retract: + try: + _Q, _r = [q.to_ring() for q in Q], r.to_ring() + except CoercionFailed: + pass + else: + Q, r = _Q, _r + + if not opt.polys: + return [q.as_expr() for q in Q], r.as_expr() + else: + return Q, r + + def contains(self, poly): + """ + Check if ``poly`` belongs the ideal generated by ``self``. + + Examples + ======== + + >>> from sympy import groebner + >>> from sympy.abc import x, y + + >>> f = 2*x**3 + y**3 + 3*y + >>> G = groebner([x**2 + y**2 - 1, x*y - 2]) + + >>> G.contains(f) + True + >>> G.contains(f + 1) + False + + """ + return self.reduce(poly)[1] == 0 + + +@public +def poly(expr, *gens, **args): + """ + Efficiently transform an expression into a polynomial. + + Examples + ======== + + >>> from sympy import poly + >>> from sympy.abc import x + + >>> poly(x*(x**2 + x - 1)**2) + Poly(x**5 + 2*x**4 - x**3 - 2*x**2 + x, x, domain='ZZ') + + """ + options.allowed_flags(args, []) + + def _poly(expr, opt): + terms, poly_terms = [], [] + + for term in Add.make_args(expr): + factors, poly_factors = [], [] + + for factor in Mul.make_args(term): + if factor.is_Add: + poly_factors.append(_poly(factor, opt)) + elif factor.is_Pow and factor.base.is_Add and \ + factor.exp.is_Integer and factor.exp >= 0: + poly_factors.append( + _poly(factor.base, opt).pow(factor.exp)) + else: + factors.append(factor) + + if not poly_factors: + terms.append(term) + else: + product = poly_factors[0] + + for factor in poly_factors[1:]: + product = product.mul(factor) + + if factors: + factor = Mul(*factors) + + if factor.is_Number: + product = product.mul(factor) + else: + product = product.mul(Poly._from_expr(factor, opt)) + + poly_terms.append(product) + + if not poly_terms: + result = Poly._from_expr(expr, opt) + else: + result = poly_terms[0] + + for term in poly_terms[1:]: + result = result.add(term) + + if terms: + term = Add(*terms) + + if term.is_Number: + result = result.add(term) + else: + result = result.add(Poly._from_expr(term, opt)) + + return result.reorder(*opt.get('gens', ()), **args) + + expr = sympify(expr) + + if expr.is_Poly: + return Poly(expr, *gens, **args) + + if 'expand' not in args: + args['expand'] = False + + opt = options.build_options(gens, args) + + return _poly(expr, opt) + + +def named_poly(n, f, K, name, x, polys): + r"""Common interface to the low-level polynomial generating functions + in orthopolys and appellseqs. + + Parameters + ========== + + n : int + Index of the polynomial, which may or may not equal its degree. + f : callable + Low-level generating function to use. + K : Domain or None + Domain in which to perform the computations. If None, use the smallest + field containing the rationals and the extra parameters of x (see below). + name : str + Name of an arbitrary individual polynomial in the sequence generated + by f, only used in the error message for invalid n. + x : seq + The first element of this argument is the main variable of all + polynomials in this sequence. Any further elements are extra + parameters required by f. + polys : bool, optional + If True, return a Poly, otherwise (default) return an expression. + """ + if n < 0: + raise ValueError("Cannot generate %s of index %s" % (name, n)) + head, tail = x[0], x[1:] + if K is None: + K, tail = construct_domain(tail, field=True) + poly = DMP(f(int(n), *tail, K), K) + if head is None: + poly = PurePoly.new(poly, Dummy('x')) + else: + poly = Poly.new(poly, head) + return poly if polys else poly.as_expr()