void acb_modular_elliptic_e(acb_t res, const acb_t m, long prec) { if (acb_is_zero(m)) { acb_const_pi(res, prec); acb_mul_2exp_si(res, res, -1); } else if (acb_is_one(m)) { acb_one(res); } else { acb_struct t[2]; acb_init(t + 0); acb_init(t + 1); acb_modular_elliptic_k_cpx(t, m, 2, prec); acb_mul(t + 1, t + 1, m, prec); acb_mul_2exp_si(t + 1, t + 1, 1); acb_add(t, t, t + 1, prec); acb_sub_ui(t + 1, m, 1, prec); acb_mul(res, t, t + 1, prec); acb_neg(res, res); acb_clear(t + 0); acb_clear(t + 1); } }
void acb_hurwitz_zeta(acb_t z, const acb_t s, const acb_t a, slong prec) { if (acb_is_one(a) && acb_is_int(s) && arf_cmpabs_2exp_si(arb_midref(acb_realref(s)), FLINT_BITS - 1) < 0) { acb_zeta_si(z, arf_get_si(arb_midref(acb_realref(s)), ARF_RND_DOWN), prec); return; } _acb_poly_zeta_cpx_series(z, s, a, 0, 1, prec); }
void acb_hypgeom_beta_lower(acb_t res, const acb_t a, const acb_t b, const acb_t z, int regularized, slong prec) { acb_t t, u; if (acb_is_zero(z) && arb_is_positive(acb_realref(a))) { acb_zero(res); return; } if (acb_is_one(z) && arb_is_positive(acb_realref(b))) { if (regularized) acb_one(res); else acb_beta(res, a, b, prec); return; } acb_init(t); acb_init(u); acb_sub_ui(t, b, 1, prec); acb_neg(t, t); acb_add_ui(u, a, 1, prec); if (regularized) { acb_hypgeom_2f1(t, a, t, u, z, 1, prec); acb_add(u, a, b, prec); acb_gamma(u, u, prec); acb_mul(t, t, u, prec); acb_rgamma(u, b, prec); acb_mul(t, t, u, prec); } else { acb_hypgeom_2f1(t, a, t, u, z, 0, prec); acb_div(t, t, a, prec); } acb_pow(u, z, a, prec); acb_mul(t, t, u, prec); acb_set(res, t); acb_clear(t); acb_clear(u); }
/* compose by poly2 = a*x^n + c, no aliasing; n >= 1 */ void _acb_poly_compose_axnc(acb_ptr res, acb_srcptr poly1, slong len1, const acb_t c, const acb_t a, slong n, slong prec) { slong i; _acb_vec_set_round(res, poly1, len1, prec); /* shift by c (c = 0 case will be fast) */ _acb_poly_taylor_shift(res, c, len1, prec); /* multiply by powers of a */ if (!acb_is_one(a)) { if (acb_equal_si(a, -1)) { for (i = 1; i < len1; i += 2) acb_neg(res + i, res + i); } else if (len1 == 2) { acb_mul(res + 1, res + 1, a, prec); } else { acb_t t; acb_init(t); acb_set(t, a); for (i = 1; i < len1; i++) { acb_mul(res + i, res + i, t, prec); if (i + 1 < len1) acb_mul(t, t, a, prec); } acb_clear(t); } } /* stretch */ for (i = len1 - 1; i >= 1 && n > 1; i--) { acb_swap(res + i * n, res + i); _acb_vec_zero(res + (i - 1) * n + 1, n - 1); } }
void acb_acos(acb_t res, const acb_t z, slong prec) { if (acb_is_one(z)) { acb_zero(res); } else { acb_t t; acb_init(t); acb_asin(res, z, prec); acb_const_pi(t, prec); acb_mul_2exp_si(t, t, -1); acb_sub(res, t, res, prec); acb_clear(t); } }
void acb_dirichlet_l_general(acb_t res, const acb_t s, const dirichlet_group_t G, const dirichlet_char_t chi, slong prec) { /* this cutoff is probably too conservative when q is large */ if (arf_cmp_d(arb_midref(acb_realref(s)), 8 + 0.5 * prec / log(prec)) >= 0) { acb_dirichlet_l_euler_product(res, s, G, chi, prec); } else { slong wp = prec + n_clog(G->phi_q, 2); acb_dirichlet_hurwitz_precomp_t pre; acb_dirichlet_hurwitz_precomp_init_num(pre, s, acb_is_one(s), G->phi_q, wp); acb_dirichlet_l_hurwitz(res, s, pre, G, chi, prec); acb_dirichlet_hurwitz_precomp_clear(pre); } }
static void _acb_hypgeom_m_1f1(acb_t res, const acb_t a, const acb_t b, const acb_t z, long prec) { if (acb_is_one(a)) { acb_hypgeom_pfq_direct(res, NULL, 0, b, 1, z, -1, prec); } else { acb_struct c[3]; c[0] = *a; c[1] = *b; acb_init(c + 2); acb_one(c + 2); acb_hypgeom_pfq_direct(res, c, 1, c + 1, 2, z, -1, prec); acb_clear(c + 2); } }
void acb_acosh(acb_t res, const acb_t z, slong prec) { if (acb_is_one(z)) { acb_zero(res); } else { acb_t t, u; acb_init(t); acb_init(u); acb_add_ui(t, z, 1, prec); acb_sub_ui(u, z, 1, prec); acb_sqrt(t, t, prec); acb_sqrt(u, u, prec); acb_mul(t, t, u, prec); acb_add(t, t, z, prec); if (!arb_is_zero(acb_imagref(z))) { acb_log(res, t, prec); } else { /* pure imaginary on (-1,1) */ arb_abs(acb_realref(u), acb_realref(z)); arb_one(acb_imagref(u)); acb_log(res, t, prec); if (arb_lt(acb_realref(u), acb_imagref(u))) arb_zero(acb_realref(res)); } acb_clear(t); acb_clear(u); } }
void _acb_poly_taylor_shift_horner(acb_ptr poly, const acb_t c, slong n, slong prec) { slong i, j; if (acb_is_one(c)) { for (i = n - 2; i >= 0; i--) for (j = i; j < n - 1; j++) acb_add(poly + j, poly + j, poly + j + 1, prec); } else if (acb_equal_si(c, -1)) { for (i = n - 2; i >= 0; i--) for (j = i; j < n - 1; j++) acb_sub(poly + j, poly + j, poly + j + 1, prec); } else if (!acb_is_zero(c)) { for (i = n - 2; i >= 0; i--) for (j = i; j < n - 1; j++) acb_addmul(poly + j, poly + j + 1, c, prec); } }
void acb_hypgeom_chebyshev_t(acb_t res, const acb_t n, const acb_t z, slong prec) { acb_t t; if (acb_is_int(n) && arf_cmpabs_2exp_si(arb_midref(acb_realref(n)), FLINT_BITS - 1) < 0) { slong k = arf_get_si(arb_midref(acb_realref(n)), ARF_RND_DOWN); acb_chebyshev_t_ui(res, FLINT_ABS(k), z, prec); return; } if (acb_is_zero(z)) { acb_mul_2exp_si(res, n, -1); acb_cos_pi(res, res, prec); return; } if (acb_is_one(z)) { acb_one(res); return; } acb_init(t); acb_set_si(t, -1); if (acb_equal(t, z)) { acb_cos_pi(res, n, prec); } else { acb_sub_ui(t, z, 1, prec); if (arf_cmpabs_2exp_si(arb_midref(acb_realref(t)), -2 - prec / 10) < 0 && arf_cmpabs_2exp_si(arb_midref(acb_imagref(t)), -2 - prec / 10) < 0) { acb_t a, c; acb_init(a); acb_init(c); acb_neg(a, n); acb_one(c); acb_mul_2exp_si(c, c, -1); acb_neg(t, t); acb_mul_2exp_si(t, t, -1); acb_hypgeom_2f1(res, a, n, c, t, 0, prec); acb_clear(a); acb_clear(c); } else if (arb_is_nonnegative(acb_realref(t))) { acb_acosh(t, z, prec); acb_mul(t, t, n, prec); acb_cosh(res, t, prec); } else { acb_acos(t, z, prec); acb_mul(t, t, n, prec); acb_cos(res, t, prec); } } acb_clear(t); }
void _acb_poly_zeta_cpx_reflect(acb_ptr t, const acb_t h, const acb_t a, int deflate, slong len, slong prec) { /* use reflection formula */ if (arf_sgn(arb_midref(acb_realref(h))) < 0 && acb_is_one(a)) { /* zeta(s) = (2*pi)**s * sin(pi*s/2) / pi * gamma(1-s) * zeta(1-s) */ acb_t pi, hcopy; acb_ptr f, s1, s2, s3, s4, u; slong i; acb_init(pi); acb_init(hcopy); f = _acb_vec_init(2); s1 = _acb_vec_init(len); s2 = _acb_vec_init(len); s3 = _acb_vec_init(len); s4 = _acb_vec_init(len); u = _acb_vec_init(len); acb_set(hcopy, h); acb_const_pi(pi, prec); /* s1 = (2*pi)**s */ acb_mul_2exp_si(pi, pi, 1); _acb_poly_pow_cpx(s1, pi, h, len, prec); acb_mul_2exp_si(pi, pi, -1); /* s2 = sin(pi*s/2) / pi */ acb_set(f, h); acb_one(f + 1); acb_mul_2exp_si(f, f, -1); acb_mul_2exp_si(f + 1, f + 1, -1); _acb_poly_sin_pi_series(s2, f, 2, len, prec); _acb_vec_scalar_div(s2, s2, len, pi, prec); /* s3 = gamma(1-s) */ acb_sub_ui(f, hcopy, 1, prec); acb_neg(f, f); acb_set_si(f + 1, -1); _acb_poly_gamma_series(s3, f, 2, len, prec); /* s4 = zeta(1-s) */ acb_sub_ui(f, hcopy, 1, prec); acb_neg(f, f); _acb_poly_zeta_cpx_series(s4, f, a, 0, len, prec); for (i = 1; i < len; i += 2) acb_neg(s4 + i, s4 + i); _acb_poly_mullow(u, s1, len, s2, len, len, prec); _acb_poly_mullow(s1, s3, len, s4, len, len, prec); _acb_poly_mullow(t, u, len, s1, len, len, prec); /* add 1/(1-(s+t)) = 1/(1-s) + t/(1-s)^2 + ... */ if (deflate) { acb_sub_ui(u, hcopy, 1, prec); acb_neg(u, u); acb_inv(u, u, prec); for (i = 1; i < len; i++) acb_mul(u + i, u + i - 1, u, prec); _acb_vec_add(t, t, u, len, prec); } acb_clear(pi); acb_clear(hcopy); _acb_vec_clear(f, 2); _acb_vec_clear(s1, len); _acb_vec_clear(s2, len); _acb_vec_clear(s3, len); _acb_vec_clear(s4, len); _acb_vec_clear(u, len); } else { _acb_poly_zeta_cpx_series(t, h, a, deflate, len, prec); } }
void _acb_poly_zeta_cpx_series(acb_ptr z, const acb_t s, const acb_t a, int deflate, slong d, slong prec) { ulong M, N; slong i, bound_prec; mag_t bound; arb_ptr vb; int is_real, const_is_real; if (d < 1) return; if (!acb_is_finite(s) || !acb_is_finite(a)) { _acb_vec_indeterminate(z, d); return; } if (acb_is_one(s) && deflate && d == 1) { acb_digamma(z, a, prec); acb_neg(z, z); if (!acb_is_finite(z)) /* todo: in digamma */ acb_indeterminate(z); return; } is_real = const_is_real = 0; if (acb_is_real(s) && acb_is_real(a)) { if (arb_is_positive(acb_realref(a))) { is_real = const_is_real = 1; } else if (arb_is_int(acb_realref(a)) && arb_is_int(acb_realref(s)) && arb_is_nonpositive(acb_realref(s))) { const_is_real = 1; } } mag_init(bound); vb = _arb_vec_init(d); bound_prec = 40 + prec / 20; _acb_poly_zeta_em_choose_param(bound, &N, &M, s, a, FLINT_MIN(d, 2), prec, bound_prec); _acb_poly_zeta_em_bound(vb, s, a, N, M, d, bound_prec); _acb_poly_zeta_em_sum(z, s, a, deflate, N, M, d, prec); for (i = 0; i < d; i++) { arb_get_mag(bound, vb + i); arb_add_error_mag(acb_realref(z + i), bound); if (!is_real && !(i == 0 && const_is_real)) arb_add_error_mag(acb_imagref(z + i), bound); } mag_clear(bound); _arb_vec_clear(vb, d); }
void _acb_hypgeom_m_1f1(acb_t res, const acb_t a, const acb_t b, const acb_t z, int regularized, slong prec, slong gamma_prec, int kummer) { if (regularized) { /* Remove singularity */ if (acb_is_int(b) && arb_is_nonpositive(acb_realref(b)) && arf_cmpabs_2exp_si(arb_midref(acb_realref(b)), 30) < 0) { acb_t c, d, t, u; slong n; n = arf_get_si(arb_midref(acb_realref(b)), ARF_RND_DOWN); acb_init(c); acb_init(d); acb_init(t); acb_init(u); acb_sub(c, a, b, prec); acb_add_ui(c, c, 1, prec); acb_neg(d, b); acb_add_ui(d, d, 2, prec); _acb_hypgeom_m_1f1(t, c, d, z, 0, prec, gamma_prec, kummer); acb_pow_ui(u, z, 1 - n, prec); acb_mul(t, t, u, prec); acb_rising_ui(u, a, 1 - n, prec); acb_mul(t, t, u, prec); arb_fac_ui(acb_realref(u), 1 - n, prec); acb_div_arb(res, t, acb_realref(u), prec); acb_clear(c); acb_clear(d); acb_clear(t); acb_clear(u); } else { acb_t t; acb_init(t); acb_rgamma(t, b, gamma_prec); _acb_hypgeom_m_1f1(res, a, b, z, 0, prec, gamma_prec, kummer); acb_mul(res, res, t, prec); acb_clear(t); } return; } /* Kummer's transformation */ if (kummer) { acb_t u, v; acb_init(u); acb_init(v); acb_sub(u, b, a, prec); acb_neg(v, z); _acb_hypgeom_m_1f1(u, u, b, v, regularized, prec, gamma_prec, 0); acb_exp(v, z, prec); acb_mul(res, u, v, prec); acb_clear(u); acb_clear(v); return; } if (acb_is_one(a)) { acb_hypgeom_pfq_direct(res, NULL, 0, b, 1, z, -1, prec); } else { acb_struct c[3]; c[0] = *a; c[1] = *b; acb_init(c + 2); acb_one(c + 2); acb_hypgeom_pfq_direct(res, c, 1, c + 1, 2, z, -1, prec); acb_clear(c + 2); } }
void _acb_poly_zeta_em_sum(acb_ptr z, const acb_t s, const acb_t a, int deflate, ulong N, ulong M, slong d, slong prec) { acb_ptr t, u, v, term, sum; acb_t Na, one; slong i; t = _acb_vec_init(d + 1); u = _acb_vec_init(d); v = _acb_vec_init(d); term = _acb_vec_init(d); sum = _acb_vec_init(d); acb_init(Na); acb_init(one); prec += 2 * (FLINT_BIT_COUNT(N) + FLINT_BIT_COUNT(d)); acb_one(one); /* sum 1/(k+a)^(s+x) */ if (acb_is_one(a) && d <= 3) _acb_poly_powsum_one_series_sieved(sum, s, N, d, prec); else if (N > 50 && flint_get_num_threads() > 1) _acb_poly_powsum_series_naive_threaded(sum, s, a, one, N, d, prec); else _acb_poly_powsum_series_naive(sum, s, a, one, N, d, prec); /* t = 1/(N+a)^(s+x); we might need one extra term for deflation */ acb_add_ui(Na, a, N, prec); _acb_poly_acb_invpow_cpx(t, Na, s, d + 1, prec); /* sum += (N+a) * 1/((s+x)-1) * t */ if (!deflate) { /* u = (N+a)^(1-(s+x)) */ acb_sub_ui(v, s, 1, prec); _acb_poly_acb_invpow_cpx(u, Na, v, d, prec); /* divide by 1/((s-1) + x) */ acb_sub_ui(v, s, 1, prec); acb_div(u, u, v, prec); for (i = 1; i < d; i++) { acb_sub(u + i, u + i, u + i - 1, prec); acb_div(u + i, u + i, v, prec); } _acb_vec_add(sum, sum, u, d, prec); } /* sum += ((N+a)^(1-(s+x)) - 1) / ((s+x) - 1) */ else { /* at s = 1, this becomes (N*t - 1)/x, i.e. just remove one coeff */ if (acb_is_one(s)) { for (i = 0; i < d; i++) acb_mul(u + i, t + i + 1, Na, prec); _acb_vec_add(sum, sum, u, d, prec); } else { /* TODO: this is numerically unstable for large derivatives, and divides by zero if s contains 1. We want a good way to evaluate the power series ((N+a)^y - 1) / y where y has nonzero constant term, without doing a division. How is this best done? */ _acb_vec_scalar_mul(t, t, d, Na, prec); acb_sub_ui(t + 0, t + 0, 1, prec); acb_sub_ui(u + 0, s, 1, prec); acb_inv(u + 0, u + 0, prec); for (i = 1; i < d; i++) acb_mul(u + i, u + i - 1, u + 0, prec); for (i = 1; i < d; i += 2) acb_neg(u + i, u + i); _acb_poly_mullow(v, u, d, t, d, d, prec); _acb_vec_add(sum, sum, v, d, prec); _acb_poly_acb_invpow_cpx(t, Na, s, d, prec); } } /* sum += u = 1/2 * t */ _acb_vec_scalar_mul_2exp_si(u, t, d, -WORD(1)); _acb_vec_add(sum, sum, u, d, prec); /* Euler-Maclaurin formula tail */ if (d < 5 || d < M / 10) _acb_poly_zeta_em_tail_naive(u, s, Na, t, M, d, prec); else _acb_poly_zeta_em_tail_bsplit(u, s, Na, t, M, d, prec); _acb_vec_add(z, sum, u, d, prec); _acb_vec_clear(t, d + 1); _acb_vec_clear(u, d); _acb_vec_clear(v, d); _acb_vec_clear(term, d); _acb_vec_clear(sum, d); acb_clear(Na); acb_clear(one); }
void acb_hypgeom_2f1(acb_t res, const acb_t a, const acb_t b, const acb_t c, const acb_t z, int flags, slong prec) { int algorithm, regularized; regularized = flags & ACB_HYPGEOM_2F1_REGULARIZED; if (!acb_is_finite(a) || !acb_is_finite(b) || !acb_is_finite(c) || !acb_is_finite(z)) { acb_indeterminate(res); return; } if (acb_is_zero(z)) { if (regularized) acb_rgamma(res, c, prec); else acb_one(res); return; } if (regularized && acb_is_int(c) && arb_is_nonpositive(acb_realref(c))) { if ((acb_is_int(a) && arb_is_nonpositive(acb_realref(a)) && arf_cmp(arb_midref(acb_realref(a)), arb_midref(acb_realref(c))) >= 0) || (acb_is_int(b) && arb_is_nonpositive(acb_realref(b)) && arf_cmp(arb_midref(acb_realref(b)), arb_midref(acb_realref(c))) >= 0)) { acb_zero(res); return; } } if (regularized && acb_eq(a, c)) { _acb_hypgeom_2f1r_reduced(res, b, c, z, prec); return; } if (regularized && acb_eq(b, c)) { _acb_hypgeom_2f1r_reduced(res, a, c, z, prec); return; } /* polynomial */ if (acb_is_int(a) && arf_sgn(arb_midref(acb_realref(a))) <= 0 && arf_cmpabs_ui(arb_midref(acb_realref(a)), prec) < 0) { acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec); return; } /* polynomial */ if (acb_is_int(b) && arf_sgn(arb_midref(acb_realref(b))) <= 0 && arf_cmpabs_ui(arb_midref(acb_realref(b)), prec) < 0) { acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec); return; } /* Try to reduce to a polynomial case using the Pfaff transformation */ /* TODO: look at flags for integer c-b, c-a here, even when c is nonexact */ if (acb_is_exact(c)) { acb_t t; acb_init(t); acb_sub(t, c, b, prec); if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t))) { acb_hypgeom_2f1_transform(res, a, b, c, z, flags, 1, prec); acb_clear(t); return; } acb_sub(t, c, a, prec); if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t))) { int f1, f2; /* When swapping a, b, also swap the flags. */ f1 = flags & ACB_HYPGEOM_2F1_AC; f2 = flags & ACB_HYPGEOM_2F1_BC; flags &= ~ACB_HYPGEOM_2F1_AC; flags &= ~ACB_HYPGEOM_2F1_BC; if (f1) flags |= ACB_HYPGEOM_2F1_BC; if (f2) flags |= ACB_HYPGEOM_2F1_AC; acb_hypgeom_2f1_transform(res, b, a, c, z, flags, 1, prec); acb_clear(t); return; } acb_clear(t); } /* special value at z = 1 */ if (acb_is_one(z)) { acb_t t, u, v; acb_init(t); acb_init(u); acb_init(v); acb_sub(t, c, a, prec); acb_sub(u, c, b, prec); acb_sub(v, t, b, prec); if (arb_is_positive(acb_realref(v))) { acb_rgamma(t, t, prec); acb_rgamma(u, u, prec); acb_mul(t, t, u, prec); acb_gamma(v, v, prec); acb_mul(t, t, v, prec); if (!regularized) { acb_gamma(v, c, prec); acb_mul(t, t, v, prec); } acb_set(res, t); } else { acb_indeterminate(res); } acb_clear(t); acb_clear(u); acb_clear(v); return; } algorithm = acb_hypgeom_2f1_choose(z); if (algorithm == 0) { acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec); } else if (algorithm >= 1 && algorithm <= 5) { acb_hypgeom_2f1_transform(res, a, b, c, z, flags, algorithm, prec); } else { acb_hypgeom_2f1_corner(res, a, b, c, z, regularized, prec); } }
void _acb_poly_inv_series(acb_ptr Qinv, acb_srcptr Q, slong Qlen, slong len, slong prec) { Qlen = FLINT_MIN(Qlen, len); acb_inv(Qinv, Q, prec); if (Qlen == 1) { _acb_vec_zero(Qinv + 1, len - 1); } else if (len == 2) { acb_mul(Qinv + 1, Qinv, Qinv, prec); acb_mul(Qinv + 1, Qinv + 1, Q + 1, prec); acb_neg(Qinv + 1, Qinv + 1); } else { slong i, blen; /* The basecase algorithm is faster for much larger Qlen or len than this, but unfortunately also much less numerically stable. */ if (Qlen == 2 || len <= 8) blen = len; else blen = FLINT_MIN(len, 4); for (i = 1; i < blen; i++) { acb_dot(Qinv + i, NULL, 1, Q + 1, 1, Qinv + i - 1, -1, FLINT_MIN(i, Qlen - 1), prec); if (!acb_is_one(Qinv)) acb_mul(Qinv + i, Qinv + i, Qinv, prec); } if (len > blen) { slong Qnlen, Wlen, W2len; acb_ptr W; W = _acb_vec_init(len); NEWTON_INIT(blen, len) NEWTON_LOOP(m, n) Qnlen = FLINT_MIN(Qlen, n); Wlen = FLINT_MIN(Qnlen + m - 1, n); W2len = Wlen - m; MULLOW(W, Q, Qnlen, Qinv, m, Wlen, prec); MULLOW(Qinv + m, Qinv, m, W + m, W2len, n - m, prec); _acb_vec_neg(Qinv + m, Qinv + m, n - m); NEWTON_END_LOOP NEWTON_END _acb_vec_clear(W, len); } } }