def test_gf_squarefree(): assert gf_sqf_list([], 11, ZZ) == (0, []) assert gf_sqf_list([1], 11, ZZ) == (1, []) assert gf_sqf_list([1, 1], 11, ZZ) == (1, [([1, 1], 1)]) assert gf_sqf_p([], 11, ZZ) is True assert gf_sqf_p([1], 11, ZZ) is True assert gf_sqf_p([1, 1], 11, ZZ) is True f = gf_from_dict({11: 1, 0: 1}, 11, ZZ) assert gf_sqf_p(f, 11, ZZ) is False assert gf_sqf_list(f, 11, ZZ) == \ (1, [([1, 1], 11)]) f = [1, 5, 8, 4] assert gf_sqf_p(f, 11, ZZ) is False assert gf_sqf_list(f, 11, ZZ) == \ (1, [([1, 1], 1), ([1, 2], 2)]) assert gf_sqf_part(f, 11, ZZ) == [1, 3, 2] f = [1, 0, 0, 2, 0, 0, 2, 0, 0, 1, 0] assert gf_sqf_list(f, 3, ZZ) == \ (1, [([1, 0], 1), ([1, 1], 3), ([1, 2], 6)])
def test_gf_factor(): assert gf_factor([], 11, ZZ) == (0, []) assert gf_factor([1], 11, ZZ) == (1, []) assert gf_factor([1, 1], 11, ZZ) == (1, [([1, 1], 1)]) assert gf_factor_sqf([], 11, ZZ) == (0, []) assert gf_factor_sqf([1], 11, ZZ) == (1, []) assert gf_factor_sqf([1, 1], 11, ZZ) == (1, [[1, 1]]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor_sqf([], 11, ZZ) == (0, []) assert gf_factor_sqf([1], 11, ZZ) == (1, []) assert gf_factor_sqf([1, 1], 11, ZZ) == (1, [[1, 1]]) config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor_sqf([], 11, ZZ) == (0, []) assert gf_factor_sqf([1], 11, ZZ) == (1, []) assert gf_factor_sqf([1, 1], 11, ZZ) == (1, [[1, 1]]) config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor_sqf(ZZ.map([]), 11, ZZ) == (0, []) assert gf_factor_sqf(ZZ.map([1]), 11, ZZ) == (1, []) assert gf_factor_sqf(ZZ.map([1, 1]), 11, ZZ) == (1, [[1, 1]]) f, p = ZZ.map([1, 0, 0, 1, 0]), 2 g = (1, [([1, 0], 1), ([1, 1], 1), ([1, 1, 1], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g g = (1, [[1, 0], [1, 1], [1, 1, 1]]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor_sqf(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor_sqf(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor_sqf(f, p, ZZ) == g f, p = gf_from_int_poly([1, -3, 1, -3, -1, -3, 1], 11), 11 g = (1, [([1, 1], 1), ([1, 5, 3], 1), ([1, 2, 3, 4], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g f, p = [1, 5, 8, 4], 11 g = (1, [([1, 1], 1), ([1, 2], 2)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g f, p = [1, 1, 10, 1, 0, 10, 10, 10, 0, 0], 11 g = (1, [([1, 0], 2), ([1, 9, 5], 1), ([1, 3, 0, 8, 5, 2], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g f, p = gf_from_dict({32: 1, 0: 1}, 11, ZZ), 11 g = (1, [([1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 10], 1), ([1, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 10], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g f, p = gf_from_dict({32: ZZ(8), 0: ZZ(5)}, 11, ZZ), 11 g = (8, [([1, 3], 1), ([1, 8], 1), ([1, 0, 9], 1), ([1, 2, 2], 1), ([1, 9, 2], 1), ([1, 0, 5, 0, 7], 1), ([1, 0, 6, 0, 7], 1), ([1, 0, 0, 0, 1, 0, 0, 0, 6], 1), ([1, 0, 0, 0, 10, 0, 0, 0, 6], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g f, p = gf_from_dict({63: ZZ(8), 0: ZZ(5)}, 11, ZZ), 11 g = (8, [([1, 7], 1), ([1, 4, 5], 1), ([1, 6, 8, 2], 1), ([1, 9, 9, 2], 1), ([1, 0, 0, 9, 0, 0, 4], 1), ([1, 2, 0, 8, 4, 6, 4], 1), ([1, 2, 3, 8, 0, 6, 4], 1), ([1, 2, 6, 0, 8, 4, 4], 1), ([1, 3, 3, 1, 6, 8, 4], 1), ([1, 5, 6, 0, 8, 6, 4], 1), ([1, 6, 2, 7, 9, 8, 4], 1), ([1, 10, 4, 7, 10, 7, 4], 1), ([1, 10, 10, 1, 4, 9, 4], 1)]) config.setup('GF_FACTOR_METHOD', 'berlekamp') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g # Gathen polynomials: x**n + x + 1 (mod p > 2**n * pi) p = ZZ(nextprime(int((2**15 * pi).evalf()))) f = gf_from_dict({15: 1, 1: 1, 0: 1}, p, ZZ) assert gf_sqf_p(f, p, ZZ) is True g = (1, [([1, 22730, 68144], 1), ([1, 81553, 77449, 86810, 4724], 1), ([1, 86276, 56779, 14859, 31575], 1), ([1, 15347, 95022, 84569, 94508, 92335], 1)]) config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g g = (1, [[1, 22730, 68144], [1, 81553, 77449, 86810, 4724], [1, 86276, 56779, 14859, 31575], [1, 15347, 95022, 84569, 94508, 92335]]) config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor_sqf(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor_sqf(f, p, ZZ) == g # Shoup polynomials: f = a_0 x**n + a_1 x**(n-1) + ... + a_n # (mod p > 2**(n-2) * pi), where a_n = a_{n-1}**2 + 1, a_0 = 1 p = ZZ(nextprime(int((2**4 * pi).evalf()))) f = ZZ.map([1, 2, 5, 26, 41, 39, 38]) assert gf_sqf_p(f, p, ZZ) is True g = (1, [([1, 44, 26], 1), ([1, 11, 25, 18, 30], 1)]) config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor(f, p, ZZ) == g g = (1, [[1, 44, 26], [1, 11, 25, 18, 30]]) config.setup('GF_FACTOR_METHOD', 'zassenhaus') assert gf_factor_sqf(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'shoup') assert gf_factor_sqf(f, p, ZZ) == g config.setup('GF_FACTOR_METHOD', 'other') pytest.raises(KeyError, lambda: gf_factor([1, 1], 11, ZZ)) config.setup('GF_FACTOR_METHOD')
def dup_zz_zassenhaus(f, K): """Factor primitive square-free polynomials in `Z[x]`. """ n = dup_degree(f) if n == 1: return [f] fc = f[-1] A = dup_max_norm(f, K) b = dup_LC(f, K) B = int(abs(K.sqrt(K(n + 1)) * 2**n * A * b)) C = int((n + 1)**(2 * n) * A**(2 * n - 1)) gamma = int(_ceil(2 * _log(C, 2))) bound = int(2 * gamma * _log(gamma)) a = [] # choose a prime number `p` such that `f` be square free in Z_p # if there are many factors in Z_p, choose among a few different `p` # the one with fewer factors for px in range(3, bound + 1): if not isprime(px) or b % px == 0: continue px = K.convert(px) F = gf_from_int_poly(f, px) if not gf_sqf_p(F, px, K): continue fsqfx = gf_factor_sqf(F, px, K)[1] a.append((px, fsqfx)) if len(fsqfx) < 15 or len(a) > 4: break p, fsqf = min(a, key=lambda x: len(x[1])) l = int(_ceil(_log(2 * B + 1, p))) modular = [gf_to_int_poly(ff, p) for ff in fsqf] g = dup_zz_hensel_lift(p, f, modular, l, K) sorted_T = range(len(g)) T = set(sorted_T) factors, s = [], 1 pl = p**l while 2 * s <= len(T): for S in subsets(sorted_T, s): # lift the constant coefficient of the product `G` of the factors # in the subset `S`; if it is does not divide `fc`, `G` does # not divide the input polynomial if b == 1: q = 1 for i in S: q = q * g[i][-1] q = q % pl if not _test_pl(fc, q, pl): continue else: G = [b] for i in S: G = dup_mul(G, g[i], K) G = dup_trunc(G, pl, K) G = dup_primitive(G, K)[1] q = G[-1] if q and fc % q != 0: continue H = [b] S = set(S) T_S = T - S if b == 1: G = [b] for i in S: G = dup_mul(G, g[i], K) G = dup_trunc(G, pl, K) for i in T_S: H = dup_mul(H, g[i], K) H = dup_trunc(H, pl, K) G_norm = dup_l1_norm(G, K) H_norm = dup_l1_norm(H, K) if G_norm * H_norm <= B: T = T_S sorted_T = [i for i in sorted_T if i not in S] G = dup_primitive(G, K)[1] f = dup_primitive(H, K)[1] factors.append(G) b = dup_LC(f, K) break else: s += 1 return factors + [f]