def dmp_zz_modular_resultant(f, g, p, u, K): """ Compute resultant of `f` and `g` modulo a prime `p`. Examples ======== >>> from sympy.polys import ring, ZZ >>> R, x,y = ring("x,y", ZZ) >>> f = x + y + 2 >>> g = 2*x*y + x + 3 >>> R.dmp_zz_modular_resultant(f, g, 5) -2*y**2 + 1 """ if not u: return gf_int(dup_prs_resultant(f, g, K)[0] % p, p) v = u - 1 n = dmp_degree(f, u) m = dmp_degree(g, u) N = dmp_degree_in(f, 1, u) M = dmp_degree_in(g, 1, u) B = n*M + m*N D, a = [K.one], -K.one r = dmp_zero(v) while dup_degree(D) <= B: while True: a += K.one if a == p: raise HomomorphismFailed('no luck') F = dmp_eval_in(f, gf_int(a, p), 1, u, K) if dmp_degree(F, v) == n: G = dmp_eval_in(g, gf_int(a, p), 1, u, K) if dmp_degree(G, v) == m: break R = dmp_zz_modular_resultant(F, G, p, v, K) e = dmp_eval(r, a, v, K) if not v: R = dup_strip([R]) e = dup_strip([e]) else: R = [R] e = [e] d = K.invert(dup_eval(D, a, K), p) d = dup_mul_ground(D, d, K) d = dmp_raise(d, v, 0, K) c = dmp_mul(d, dmp_sub(R, e, v, K), v, K) r = dmp_add(r, c, v, K) r = dmp_ground_trunc(r, p, v, K) D = dup_mul(D, [K.one, -a], K) D = dup_trunc(D, p, K) return r
def test_pickling_polys_errors(): from sympy.polys.polyerrors import ( ExactQuotientFailed, OperationNotSupported, HeuristicGCDFailed, HomomorphismFailed, IsomorphismFailed, ExtraneousFactors, EvaluationFailed, RefinementFailed, CoercionFailed, NotInvertible, NotReversible, NotAlgebraic, DomainError, PolynomialError, UnificationFailed, GeneratorsError, GeneratorsNeeded, ComputationFailed, UnivariatePolynomialError, MultivariatePolynomialError, PolificationFailed, OptionError, FlagError) x = Symbol('x') # TODO: TypeError: __init__() takes at least 3 arguments (1 given) # for c in (ExactQuotientFailed, ExactQuotientFailed(x, 3*x, ZZ)): # check(c) # TODO: TypeError: can't pickle instancemethod objects # for c in (OperationNotSupported, OperationNotSupported(Poly(x), Poly.gcd)): # check(c) for c in (HeuristicGCDFailed, HeuristicGCDFailed()): check(c) for c in (HomomorphismFailed, HomomorphismFailed()): check(c) for c in (IsomorphismFailed, IsomorphismFailed()): check(c) for c in (ExtraneousFactors, ExtraneousFactors()): check(c) for c in (EvaluationFailed, EvaluationFailed()): check(c) for c in (RefinementFailed, RefinementFailed()): check(c) for c in (CoercionFailed, CoercionFailed()): check(c) for c in (NotInvertible, NotInvertible()): check(c) for c in (NotReversible, NotReversible()): check(c) for c in (NotAlgebraic, NotAlgebraic()): check(c) for c in (DomainError, DomainError()): check(c) for c in (PolynomialError, PolynomialError()): check(c) for c in (UnificationFailed, UnificationFailed()): check(c) for c in (GeneratorsError, GeneratorsError()): check(c) for c in (GeneratorsNeeded, GeneratorsNeeded()): check(c) # TODO: PicklingError: Can't pickle <function <lambda> at 0x38578c0>: it's not found as __main__.<lambda> # for c in (ComputationFailed, ComputationFailed(lambda t: t, 3, None)): # check(c) for c in (UnivariatePolynomialError, UnivariatePolynomialError()): check(c) for c in (MultivariatePolynomialError, MultivariatePolynomialError()): check(c) # TODO: TypeError: __init__() takes at least 3 arguments (1 given) # for c in (PolificationFailed, PolificationFailed({}, x, x, False)): # check(c) for c in (OptionError, OptionError()): check(c) for c in (FlagError, FlagError()): check(c)
def dmp_zz_modular_resultant(f, g, p, u, K): """ Compute resultant of `f` and `g` modulo a prime `p`. Examples ======== >>> from sympy.polys.domains import ZZ >>> from sympy.polys.euclidtools import dmp_zz_modular_resultant >>> f = ZZ.map([[1], [1, 2]]) >>> g = ZZ.map([[2, 1], [3]]) >>> dmp_zz_modular_resultant(f, g, ZZ(5), 1, ZZ) [-2, 0, 1] """ if not u: return gf_int(dup_prs_resultant(f, g, K)[0] % p, p) v = u - 1 n = dmp_degree(f, u) m = dmp_degree(g, u) N = dmp_degree_in(f, 1, u) M = dmp_degree_in(g, 1, u) B = n * M + m * N D, a = [K.one], -K.one r = dmp_zero(v) while dup_degree(D) <= B: while True: a += K.one if a == p: raise HomomorphismFailed('no luck') F = dmp_eval_in(f, gf_int(a, p), 1, u, K) if dmp_degree(F, v) == n: G = dmp_eval_in(g, gf_int(a, p), 1, u, K) if dmp_degree(G, v) == m: break R = dmp_zz_modular_resultant(F, G, p, v, K) e = dmp_eval(r, a, v, K) if not v: R = dup_strip([R]) e = dup_strip([e]) else: R = [R] e = [e] d = K.invert(dup_eval(D, a, K), p) d = dup_mul_ground(D, d, K) d = dmp_raise(d, v, 0, K) c = dmp_mul(d, dmp_sub(R, e, v, K), v, K) r = dmp_add(r, c, v, K) r = dmp_ground_trunc(r, p, v, K) D = dup_mul(D, [K.one, -a], K) D = dup_trunc(D, p, K) return r