Source code for diofant.polys.specialpolys

"""Functions for generating interesting polynomials, e.g. for benchmarking. """

from ..core import Add, Dummy, Integer, Mul, Symbol, symbols, sympify
from ..domains import ZZ
from ..functions import sqrt
from ..ntheory import nextprime
from ..utilities import subsets
from .densearith import dmp_add_term, dmp_mul, dmp_neg, dmp_sqr
from .densebasic import (dmp_from_dict, dmp_ground, dmp_one, dmp_raise,
                         dmp_to_dict, dmp_zero, dup_random)
from .factortools import dup_zz_cyclotomic_poly
from .polytools import Poly, PurePoly
from .polyutils import _analyze_gens
from .rings import ring


__all__ = ('swinnerton_dyer_poly', 'cyclotomic_poly', 'symmetric_poly',
           'random_poly', 'interpolating_poly')


[docs]def swinnerton_dyer_poly(n, x=None, **args): """Generates n-th Swinnerton-Dyer polynomial in `x`. """ from .numberfields import minimal_polynomial if n <= 0: raise ValueError( "can't generate Swinnerton-Dyer polynomial of order %s" % n) if x is not None: x = sympify(x) else: x = Dummy('x') if n == 1: ex = x**2 - 2 elif n == 2: ex = x**4 - 10*x**2 + 1 elif n == 3: ex = x**8 - 40*x**6 + 352*x**4 - 960*x**2 + 576 else: p = 2 a = [sqrt(2)] for i in range(2, n + 1): p = nextprime(p) a.append(sqrt(p)) ex = minimal_polynomial(Add(*a))(x) if not args.get('polys', False): return ex else: return PurePoly(ex, x)
[docs]def cyclotomic_poly(n, x=None, **args): """Generates cyclotomic polynomial of order `n` in `x`. """ if n <= 0: raise ValueError( "can't generate cyclotomic polynomial of order %s" % n) poly = dup_zz_cyclotomic_poly(int(n), ZZ) if x is not None: poly = Poly(poly, x) else: poly = PurePoly(poly, Dummy('x')) if not args.get('polys', False): return poly.as_expr() else: return poly
[docs]def symmetric_poly(n, *gens, **args): """Generates symmetric polynomial of order `n`. """ gens = _analyze_gens(gens) if n < 0 or n > len(gens) or not gens: raise ValueError("can't generate symmetric polynomial of order %s for %s" % (n, gens)) elif not n: poly = Integer(1) else: poly = Add(*[Mul(*s) for s in subsets(gens, int(n))]) if not args.get('polys', False): return poly else: return Poly(poly, *gens)
[docs]def random_poly(x, n, inf, sup, domain=ZZ, polys=False, percent=None): """Return a polynomial of degree ``n`` with coefficients in ``[inf, sup]``. """ poly = Poly(dup_random(n, inf, sup, domain, percent), x, domain=domain) if not polys: return poly.as_expr() else: return poly
[docs]def interpolating_poly(n, x, X='x', Y='y'): """Construct Lagrange interpolating polynomial for ``n`` data points. """ if isinstance(X, str): X = symbols("%s:%s" % (X, n)) if isinstance(Y, str): Y = symbols("%s:%s" % (Y, n)) coeffs = [] for i in range(n): numer = [] denom = [] for j in range(n): if i == j: continue numer.append(x - X[j]) denom.append(X[i] - X[j]) numer = Mul(*numer) denom = Mul(*denom) coeffs.append(numer/denom) return Add(*[coeff*y for coeff, y in zip(coeffs, Y)])
def fateman_poly_F_1(n): """Fateman's GCD benchmark: trivial GCD """ Y = [Symbol('y_' + str(i)) for i in range(n + 1)] return tuple(map(lambda p: Poly(dmp_to_dict(p, n), *Y), dmp_fateman_poly_F_1(n, ZZ))) def dmp_fateman_poly_F_1(n, K): """Fateman's GCD benchmark: trivial GCD """ u = [K(1), K(0)] for i in range(n): u = [dmp_one(i, K), u] v = [K(1), K(0), K(0)] for i in range(n): v = [dmp_one(i, K), dmp_zero(i), v] m = n - 1 U = dmp_add_term(u, dmp_ground(K(1), m), 0, n, K) V = dmp_add_term(u, dmp_ground(K(2), m), 0, n, K) f = [[-K(3), K(0)], [], [K(1), K(0), -K(1)]] W = dmp_add_term(v, dmp_ground(K(1), m), 0, n, K) Y = dmp_raise(f, m, 1, K) F = dmp_mul(U, V, n, K) G = dmp_mul(W, Y, n, K) H = dmp_one(n, K) return F, G, H def fateman_poly_F_2(n): """Fateman's GCD benchmark: linearly dense quartic inputs """ Y = [Symbol('y_' + str(i)) for i in range(n + 1)] return tuple(map(lambda p: Poly(dmp_to_dict(p, n), *Y), dmp_fateman_poly_F_2(n, ZZ))) def dmp_fateman_poly_F_2(n, K): """Fateman's GCD benchmark: linearly dense quartic inputs """ u = [K(1), K(0)] for i in range(n - 1): u = [dmp_one(i, K), u] m = n - 1 v = dmp_add_term(u, dmp_ground(K(2), m - 1), 0, n, K) f = dmp_sqr([dmp_one(m, K), dmp_neg(v, m, K)], n, K) g = dmp_sqr([dmp_one(m, K), v], n, K) v = dmp_add_term(u, dmp_one(m - 1, K), 0, n, K) h = dmp_sqr([dmp_one(m, K), v], n, K) return dmp_mul(f, h, n, K), dmp_mul(g, h, n, K), h def fateman_poly_F_3(n): """Fateman's GCD benchmark: sparse inputs (deg f ~ vars f) """ Y = [Symbol('y_' + str(i)) for i in range(n + 1)] return tuple(map(lambda p: Poly(dmp_to_dict(p, n), *Y), dmp_fateman_poly_F_3(n, ZZ))) def dmp_fateman_poly_F_3(n, K): """Fateman's GCD benchmark: sparse inputs (deg f ~ vars f) """ u = dmp_from_dict({(n + 1,): K.one}, 0, K) for i in range(n - 1): u = dmp_add_term([u], dmp_one(i, K), n + 1, i + 1, K) v = dmp_add_term(u, dmp_ground(K(2), n - 2), 0, n, K) f = dmp_sqr( dmp_add_term([dmp_neg(v, n - 1, K)], dmp_one(n - 1, K), n + 1, n, K), n, K) g = dmp_sqr(dmp_add_term([v], dmp_one(n - 1, K), n + 1, n, K), n, K) v = dmp_add_term(u, dmp_one(n - 2, K), 0, n - 1, K) h = dmp_sqr(dmp_add_term([v], dmp_one(n - 1, K), n + 1, n, K), n, K) return dmp_mul(f, h, n, K), dmp_mul(g, h, n, K), h # A few useful polynomials from Wang's paper ('78). def _f_0(): R, x, y, z = ring("x,y,z", ZZ) return x**2*y*z**2 + 2*x**2*y*z + 3*x**2*y + 2*x**2 + 3*x + 4*y**2*z**2 + 5*y**2*z + 6*y**2 + y*z**2 + 2*y*z + y + 1 def _f_1(): R, x, y, z = ring("x,y,z", ZZ) return x**3*y*z + x**2*y**2*z**2 + x**2*y**2 + 20*x**2*y*z + 30*x**2*y + x**2*z**2 + 10*x**2*z + x*y**3*z + 30*x*y**2*z + 20*x*y**2 + x*y*z**3 + 10*x*y*z**2 + x*y*z + 610*x*y + 20*x*z**2 + 230*x*z + 300*x + y**2*z**2 + 10*y**2*z + 30*y*z**2 + 320*y*z + 200*y + 600*z + 6000 def _f_2(): R, x, y, z = ring("x,y,z", ZZ) return x**5*y**3 + x**5*y**2*z + x**5*y*z**2 + x**5*z**3 + x**3*y**2 + x**3*y*z + 90*x**3*y + 90*x**3*z + x**2*y**2*z - 11*x**2*y**2 + x**2*z**3 - 11*x**2*z**2 + y*z - 11*y + 90*z - 990 def _f_3(): R, x, y, z = ring("x,y,z", ZZ) return x**5*y**2 + x**4*z**4 + x**4 + x**3*y**3*z + x**3*z + x**2*y**4 + x**2*y**3*z**3 + x**2*y*z**5 + x**2*y*z + x*y**2*z**4 + x*y**2 + x*y*z**7 + x*y*z**3 + x*y*z**2 + y**2*z + y*z**4 def _f_4(): R, x, y, z = ring("x,y,z", ZZ) return -x**9*y**8*z - x**8*y**5*z**3 - x**7*y**12*z**2 - 5*x**7*y**8 - x**6*y**9*z**4 + x**6*y**7*z**3 + 3*x**6*y**7*z - 5*x**6*y**5*z**2 - x**6*y**4*z**3 + x**5*y**4*z**5 + 3*x**5*y**4*z**3 - x**5*y*z**5 + x**4*y**11*z**4 + 3*x**4*y**11*z**2 - x**4*y**8*z**4 + 5*x**4*y**7*z**2 + 15*x**4*y**7 - 5*x**4*y**4*z**2 + x**3*y**8*z**6 + 3*x**3*y**8*z**4 - x**3*y**5*z**6 + 5*x**3*y**4*z**4 + 15*x**3*y**4*z**2 + x**3*y**3*z**5 + 3*x**3*y**3*z**3 - 5*x**3*y*z**4 + x**2*z**7 + 3*x**2*z**5 + x*y**7*z**6 + 3*x*y**7*z**4 + 5*x*y**3*z**4 + 15*x*y**3*z**2 + y**4*z**8 + 3*y**4*z**6 + 5*z**6 + 15*z**4 def _f_5(): R, x, y, z = ring("x,y,z", ZZ) return -x**3 - 3*x**2*y + 3*x**2*z - 3*x*y**2 + 6*x*y*z - 3*x*z**2 - y**3 + 3*y**2*z - 3*y*z**2 + z**3 def _f_6(): R, x, y, z, t = ring("x,y,z,t", ZZ) return 2115*x**4*y + 45*x**3*z**3*t**2 - 45*x**3*t**2 - 423*x*y**4 - 47*x*y**3 + 141*x*y*z**3 + 94*x*y*z*t - 9*y**3*z**3*t**2 + 9*y**3*t**2 - y**2*z**3*t**2 + y**2*t**2 + 3*z**6*t**2 + 2*z**4*t**3 - 3*z**3*t**2 - 2*z*t**3 def _w_1(): R, x, y, z = ring("x,y,z", ZZ) return 4*x**6*y**4*z**2 + 4*x**6*y**3*z**3 - 4*x**6*y**2*z**4 - 4*x**6*y*z**5 + x**5*y**4*z**3 + 12*x**5*y**3*z - x**5*y**2*z**5 + 12*x**5*y**2*z**2 - 12*x**5*y*z**3 - 12*x**5*z**4 + 8*x**4*y**4 + 6*x**4*y**3*z**2 + 8*x**4*y**3*z - 4*x**4*y**2*z**4 + 4*x**4*y**2*z**3 - 8*x**4*y**2*z**2 - 4*x**4*y*z**5 - 2*x**4*y*z**4 - 8*x**4*y*z**3 + 2*x**3*y**4*z + x**3*y**3*z**3 - x**3*y**2*z**5 - 2*x**3*y**2*z**3 + 9*x**3*y**2*z - 12*x**3*y*z**3 + 12*x**3*y*z**2 - 12*x**3*z**4 + 3*x**3*z**3 + 6*x**2*y**3 - 6*x**2*y**2*z**2 + 8*x**2*y**2*z - 2*x**2*y*z**4 - 8*x**2*y*z**3 + 2*x**2*y*z**2 + 2*x*y**3*z - 2*x*y**2*z**3 - 3*x*y*z + 3*x*z**3 - 2*y**2 + 2*y*z**2 def _w_2(): R, x, y = ring("x,y", ZZ) return 24*x**8*y**3 + 48*x**8*y**2 + 24*x**7*y**5 - 72*x**7*y**2 + 25*x**6*y**4 + 2*x**6*y**3 + 4*x**6*y + 8*x**6 + x**5*y**6 + x**5*y**3 - 12*x**5 + x**4*y**5 - x**4*y**4 - 2*x**4*y**3 + 292*x**4*y**2 - x**3*y**6 + 3*x**3*y**3 - x**2*y**5 + 12*x**2*y**3 + 48*x**2 - 12*y**3 def f_polys(): return _f_0(), _f_1(), _f_2(), _f_3(), _f_4(), _f_5(), _f_6() def w_polys(): return _w_1(), _w_2()