def test_dup_random(): f = dup_random(0, -10, 10, ZZ) assert dmp_degree_in(f, 0, 0) == 0 assert all(-10 <= c <= 10 for c in f) f = dup_random(1, -20, 20, ZZ) assert dmp_degree_in(f, 0, 0) == 1 assert all(-20 <= c <= 20 for c in f) f = dup_random(2, -30, 30, ZZ) assert dmp_degree_in(f, 0, 0) == 2 assert all(-30 <= c <= 30 for c in f) f = dup_random(3, -40, 40, ZZ) assert dmp_degree_in(f, 0, 0) == 3 assert all(-40 <= c <= 40 for c in f) f = dup_random(3, -400, 400, ZZ) assert dmp_degree_in(f, 0, 0) == 3 assert all(-400 <= c <= 400 for c in f) random.seed(11) assert dup_random(10, -1, 1, ZZ) == [1, 0, 0, -1, 0, 0, -1, 1, 1, 0, 1] for i in range(10): f = dup_random(3, -10, 10, ZZ, percent=50) assert f[0] assert len([c for c in f if c == 0]) == 2
def dmp_zz_wang_hensel_lifting(f, H, LC, A, p, u, K): """Wang/EEZ: Parallel Hensel lifting algorithm. """ S, n, v = [f], len(A), u - 1 H = list(H) for i, a in enumerate(reversed(A[1:])): s = dmp_eval_in(S[0], a, n - i, u - i, K) S.insert(0, dmp_ground_trunc(s, p, v - i, K)) d = max(dmp_degree_list(f, u)[1:]) for j, s, a in zip(range(2, n + 2), S, A): G, w = list(H), j - 1 I, J = A[:j - 2], A[j - 1:] for i, (h, lc) in enumerate(zip(H, LC)): lc = dmp_ground_trunc(dmp_eval_tail(lc, J, v, K), p, w - 1, K) H[i] = [lc] + dmp_raise(h[1:], 1, w - 1, K) m = dmp_nest([K.one, -a], w, K) M = dmp_one(w, K) c = dmp_sub(s, dmp_expand(H, w, K), w, K) dj = dmp_degree_in(s, w, w) for k in K.map(range(0, dj)): if dmp_zero_p(c, w): break M = dmp_mul(M, m, w, K) C = dmp_diff_eval_in(c, k + 1, a, w, w, K) if not dmp_zero_p(C, w - 1): C = dmp_quo_ground(C, K.factorial(k + 1), w - 1, K) T = dmp_zz_diophantine(G, C, I, d, p, w - 1, K) for i, (h, t) in enumerate(zip(H, T)): h = dmp_add_mul(h, dmp_raise(t, 1, w - 1, K), M, w, K) H[i] = dmp_ground_trunc(h, p, w, K) h = dmp_sub(s, dmp_expand(H, w, K), w, K) c = dmp_ground_trunc(h, p, w, K) if dmp_expand(H, u, K) != f: raise ExtraneousFactors # pragma: no cover else: return H
def test_dmp_degree_in(): assert dmp_degree_in([[[]]], 0, 2) == -oo assert dmp_degree_in([[[]]], 1, 2) == -oo assert dmp_degree_in([[[]]], 2, 2) == -oo assert dmp_degree_in([[[1]]], 0, 2) == 0 assert dmp_degree_in([[[1]]], 1, 2) == 0 assert dmp_degree_in([[[1]]], 2, 2) == 0 assert dmp_degree_in(f_4, 0, 2) == 9 assert dmp_degree_in(f_4, 1, 2) == 12 assert dmp_degree_in(f_4, 2, 2) == 8 assert dmp_degree_in(f_6, 0, 2) == 4 assert dmp_degree_in(f_6, 1, 2) == 4 assert dmp_degree_in(f_6, 2, 2) == 6 assert dmp_degree_in(f_6, 3, 3) == 3 pytest.raises(IndexError, lambda: dmp_degree_in([[1]], -5, 1))
def dmp_zz_modular_resultant(f, g, p, u, K): """ Compute resultant of `f` and `g` modulo a prime `p`. Examples ======== >>> from diofant.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