/* F = 1 + U + U^2 + ... = 1/(1-U) assuming that U[0] is positive; indeterminate if not convergent */ static void arb_poly_geometric_sum(arb_poly_t F, const arb_poly_t U, long len, long prec) { if (U->length == 0) { arb_poly_one(F); return; } arb_poly_add_si(F, U, -1, prec); arb_poly_neg(F, F); if (F->length > 0 && arb_is_positive(F->coeffs)) { arb_poly_inv_series(F, F, len, prec); } else { arb_poly_fit_length(F, len); _arb_vec_indeterminate(F->coeffs, len); _arb_poly_set_length(F, len); } }
/* F = 1 + U + U^2 + U^3 + ... = 1/(1-U) U = product of (1 + |A-B|/(|B[0] - |B[1:]|) product of (1 / (|B[0] - |B[1:]|)) * |Z| */ void acb_hypgeom_pfq_series_bound_factor(arb_poly_t F, const acb_poly_struct * a, long p, const acb_poly_struct * b, long q, const acb_poly_t z, long n, long len, long prec) { long i; arb_poly_t T, U, V; acb_poly_t BN, AB; /* not convergent */ if (p > q) { arb_poly_fit_length(F, len); _arb_vec_indeterminate(F->coeffs, len); _arb_poly_set_length(F, len); return; } arb_poly_init(T); arb_poly_init(U); arb_poly_init(V); acb_poly_init(BN); acb_poly_init(AB); acb_poly_majorant(U, z, prec); for (i = 0; i < q; i++) { acb_poly_add_si(BN, b + i, n, prec); if (acb_poly_length(BN) != 0 && arb_is_positive(acb_realref(BN->coeffs))) { if (i < p) { /* 1 + |a-b|/reciprocal_majorant(b + n) */ acb_poly_sub(AB, a + i, b + i, prec); acb_poly_majorant(T, AB, prec); acb_poly_reciprocal_majorant(V, BN, prec); arb_poly_div_series(T, T, V, len, prec); arb_poly_add_si(T, T, 1, prec); arb_poly_mullow(U, U, T, len, prec); } else { acb_poly_reciprocal_majorant(T, BN, prec); arb_poly_div_series(U, U, T, len, prec); } } else { arb_poly_fit_length(U, len); _arb_vec_indeterminate(U->coeffs, len); _arb_poly_set_length(U, len); break; } } /* F = 1/(1-U) */ arb_poly_geometric_sum(F, U, len, prec); arb_poly_clear(T); arb_poly_clear(U); arb_poly_clear(V); acb_poly_clear(BN); acb_poly_clear(AB); }
int main() { slong iter; flint_rand_t state; flint_printf("digamma_series...."); fflush(stdout); flint_randinit(state); for (iter = 0; iter < 1000; iter++) { slong m, n1, n2, rbits1, rbits2, rbits3; arb_poly_t a, b, c, d; rbits1 = 2 + n_randint(state, 300); rbits2 = 2 + n_randint(state, 300); rbits3 = 2 + n_randint(state, 300); m = n_randint(state, 25); n1 = n_randint(state, 25); n2 = n_randint(state, 25); arb_poly_init(a); arb_poly_init(b); arb_poly_init(c); arb_poly_init(d); arb_poly_randtest(a, state, m, rbits1, 10); arb_poly_digamma_series(b, a, n1, rbits2); arb_poly_digamma_series(c, a, n2, rbits3); arb_poly_set(d, b); arb_poly_truncate(d, FLINT_MIN(n1, n2)); arb_poly_truncate(c, FLINT_MIN(n1, n2)); if (!arb_poly_overlaps(c, d)) { flint_printf("FAIL\n\n"); flint_printf("n1 = %wd, n2 = %wd, bits2 = %wd, bits3 = %wd\n", n1, n2, rbits2, rbits3); flint_printf("a = "); arb_poly_printd(a, 50); flint_printf("\n\n"); flint_printf("b = "); arb_poly_printd(b, 50); flint_printf("\n\n"); flint_printf("c = "); arb_poly_printd(c, 50); flint_printf("\n\n"); abort(); } /* check psi(a) + 1/a = psi(a+1) */ arb_poly_inv_series(c, a, n1, rbits2); arb_poly_add(c, b, c, rbits2); arb_poly_add_si(d, a, 1, rbits2); arb_poly_digamma_series(d, d, n1, rbits2); if (!arb_poly_overlaps(c, d)) { flint_printf("FAIL (functional equation)\n\n"); flint_printf("a = "); arb_poly_printd(a, 15); flint_printf("\n\n"); flint_printf("b = "); arb_poly_printd(b, 15); flint_printf("\n\n"); flint_printf("c = "); arb_poly_printd(c, 15); flint_printf("\n\n"); flint_printf("d = "); arb_poly_printd(d, 15); flint_printf("\n\n"); abort(); } arb_poly_digamma_series(a, a, n1, rbits2); if (!arb_poly_overlaps(a, b)) { flint_printf("FAIL (aliasing)\n\n"); abort(); } arb_poly_clear(a); arb_poly_clear(b); arb_poly_clear(c); arb_poly_clear(d); } flint_randclear(state); flint_cleanup(); flint_printf("PASS\n"); return EXIT_SUCCESS; }
int main() { slong iter; flint_rand_t state; flint_printf("rgamma_series...."); fflush(stdout); flint_randinit(state); for (iter = 0; iter < 2000 * arb_test_multiplier(); iter++) { slong m, n1, n2, qbits, rbits1, rbits2, rbits3; fmpq_poly_t A; arb_poly_t a, b, c, d; qbits = 2 + n_randint(state, 200); rbits1 = 2 + n_randint(state, 400); rbits2 = 2 + n_randint(state, 400); rbits3 = 2 + n_randint(state, 400); m = 1 + n_randint(state, 30); n1 = 1 + n_randint(state, 30); n2 = 1 + n_randint(state, 30); fmpq_poly_init(A); arb_poly_init(a); arb_poly_init(b); arb_poly_init(c); arb_poly_init(d); fmpq_poly_randtest_not_zero(A, state, m, qbits); arb_poly_set_fmpq_poly(a, A, rbits1); arb_poly_rgamma_series(b, a, n1, rbits2); arb_poly_rgamma_series(c, a, n2, rbits3); arb_poly_set(d, b); arb_poly_truncate(d, FLINT_MIN(n1, n2)); arb_poly_truncate(c, FLINT_MIN(n1, n2)); if (!arb_poly_overlaps(c, d)) { flint_printf("FAIL\n\n"); flint_printf("n1 = %wd, n2 = %wd, bits2 = %wd, bits3 = %wd\n", n1, n2, rbits2, rbits3); flint_printf("A = "); fmpq_poly_print(A); flint_printf("\n\n"); flint_printf("a = "); arb_poly_printd(a, 15); flint_printf("\n\n"); flint_printf("b = "); arb_poly_printd(b, 15); flint_printf("\n\n"); flint_printf("c = "); arb_poly_printd(c, 15); flint_printf("\n\n"); abort(); } /* check rgamma(a) = a gamma(a+1) */ arb_poly_add_si(d, a, 1, rbits2); arb_poly_rgamma_series(d, d, n1, rbits2); arb_poly_mullow(c, d, a, n1, rbits2); if (!arb_poly_overlaps(b, c)) { flint_printf("FAIL (functional equation, n1 = %wd)\n\n", n1); flint_printf("A = "); fmpq_poly_print(A); flint_printf("\n\n"); flint_printf("a = "); arb_poly_printd(a, 15); flint_printf("\n\n"); flint_printf("b = "); arb_poly_printd(b, 15); flint_printf("\n\n"); flint_printf("c = "); arb_poly_printd(c, 15); flint_printf("\n\n"); flint_printf("d = "); arb_poly_printd(d, 15); flint_printf("\n\n"); abort(); } arb_poly_rgamma_series(a, a, n1, rbits2); if (!arb_poly_overlaps(a, b)) { flint_printf("FAIL (aliasing)\n\n"); abort(); } fmpq_poly_clear(A); arb_poly_clear(a); arb_poly_clear(b); arb_poly_clear(c); arb_poly_clear(d); } flint_randclear(state); flint_cleanup(); flint_printf("PASS\n"); return EXIT_SUCCESS; }