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; 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; } 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); _acb_poly_zeta_em_choose_param(bound, &N, &M, s, a, FLINT_MIN(d, 2), prec, MAG_BITS); _acb_poly_zeta_em_bound(vb, s, a, N, M, d, MAG_BITS); _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_poly_powsum_one_series_sieved(acb_ptr z, const acb_t s, slong n, slong len, slong prec) { slong * divisors; slong powers_alloc; slong i, j, k, ibound, kprev, power_of_two, horner_point; int critical_line, integer; acb_ptr powers; acb_ptr t, u, x; acb_ptr p1, p2; arb_t logk, v, w; critical_line = arb_is_exact(acb_realref(s)) && (arf_cmp_2exp_si(arb_midref(acb_realref(s)), -1) == 0); integer = arb_is_zero(acb_imagref(s)) && arb_is_int(acb_realref(s)); divisors = flint_calloc(n / 2 + 1, sizeof(slong)); powers_alloc = (n / 6 + 1) * len; powers = _acb_vec_init(powers_alloc); ibound = n_sqrt(n); for (i = 3; i <= ibound; i += 2) if (DIVISOR(i) == 0) for (j = i * i; j <= n; j += 2 * i) DIVISOR(j) = i; t = _acb_vec_init(len); u = _acb_vec_init(len); x = _acb_vec_init(len); arb_init(logk); arb_init(v); arb_init(w); power_of_two = 1; while (power_of_two * 2 <= n) power_of_two *= 2; horner_point = n / power_of_two; _acb_vec_zero(z, len); kprev = 0; COMPUTE_POWER(x, 2, kprev); for (k = 1; k <= n; k += 2) { /* t = k^(-s) */ if (DIVISOR(k) == 0) { COMPUTE_POWER(t, k, kprev); } else { p1 = POWER(DIVISOR(k)); p2 = POWER(k / DIVISOR(k)); if (len == 1) acb_mul(t, p1, p2, prec); else _acb_poly_mullow(t, p1, len, p2, len, len, prec); } if (k * 3 <= n) _acb_vec_set(POWER(k), t, len); _acb_vec_add(u, u, t, len, prec); while (k == horner_point && power_of_two != 1) { _acb_poly_mullow(t, z, len, x, len, len, prec); _acb_vec_add(z, t, u, len, prec); power_of_two /= 2; horner_point = n / power_of_two; horner_point -= (horner_point % 2 == 0); } } _acb_poly_mullow(t, z, len, x, len, len, prec); _acb_vec_add(z, t, u, len, prec); flint_free(divisors); _acb_vec_clear(powers, powers_alloc); _acb_vec_clear(t, len); _acb_vec_clear(u, len); _acb_vec_clear(x, len); arb_clear(logk); arb_clear(v); arb_clear(w); }
void _arb_poly_rgamma_series(arb_ptr res, arb_srcptr h, long hlen, long len, long prec) { int reflect; long i, rflen, r, n, wp; arb_ptr t, u, v; arb_struct f[2]; hlen = FLINT_MIN(hlen, len); wp = prec + FLINT_BIT_COUNT(prec); t = _arb_vec_init(len); u = _arb_vec_init(len); v = _arb_vec_init(len); arb_init(f); arb_init(f + 1); /* use zeta values at small integers */ if (arb_is_int(h) && (arf_cmpabs_ui(arb_midref(h), prec / 2) < 0)) { r = arf_get_si(arb_midref(h), ARF_RND_DOWN); _arb_poly_lgamma_series_at_one(u, len, wp); _arb_vec_neg(u, u, len); _arb_poly_exp_series(t, u, len, len, wp); if (r == 1) { _arb_vec_swap(v, t, len); } else if (r <= 0) { arb_set(f, h); arb_one(f + 1); rflen = FLINT_MIN(len, 2 - r); _arb_poly_rising_ui_series(u, f, FLINT_MIN(2, len), 1 - r, rflen, wp); _arb_poly_mullow(v, t, len, u, rflen, len, wp); } else { arb_one(f); arb_one(f + 1); rflen = FLINT_MIN(len, r); _arb_poly_rising_ui_series(v, f, FLINT_MIN(2, len), r - 1, rflen, wp); /* TODO: use div_series? */ _arb_poly_inv_series(u, v, rflen, len, wp); _arb_poly_mullow(v, t, len, u, len, len, wp); } } else { /* otherwise use Stirling series */ arb_gamma_stirling_choose_param(&reflect, &r, &n, h, 1, 0, wp); /* rgamma(h) = (gamma(1-h+r) sin(pi h)) / (rf(1-h, r) * pi), h = h0 + t*/ if (reflect) { /* u = gamma(r+1-h) */ arb_sub_ui(f, h, r + 1, wp); arb_neg(f, f); _arb_poly_gamma_stirling_eval(t, f, n, len, wp); _arb_poly_exp_series(u, t, len, len, wp); for (i = 1; i < len; i += 2) arb_neg(u + i, u + i); /* v = sin(pi x) */ arb_const_pi(f + 1, wp); arb_mul(f, h, f + 1, wp); _arb_poly_sin_series(v, f, 2, len, wp); _arb_poly_mullow(t, u, len, v, len, len, wp); /* rf(1-h,r) * pi */ if (r == 0) { arb_const_pi(u, wp); _arb_vec_scalar_div(v, t, len, u, wp); } else { arb_sub_ui(f, h, 1, wp); arb_neg(f, f); arb_set_si(f + 1, -1); rflen = FLINT_MIN(len, r + 1); _arb_poly_rising_ui_series(v, f, FLINT_MIN(2, len), r, rflen, wp); arb_const_pi(u, wp); _arb_vec_scalar_mul(v, v, rflen, u, wp); /* divide by rising factorial */ /* TODO: might better to use div_series, when it has a good basecase */ _arb_poly_inv_series(u, v, rflen, len, wp); _arb_poly_mullow(v, t, len, u, len, len, wp); } } else { /* rgamma(h) = rgamma(h+r) rf(h,r) */ if (r == 0) { arb_add_ui(f, h, r, wp); _arb_poly_gamma_stirling_eval(t, f, n, len, wp); _arb_vec_neg(t, t, len); _arb_poly_exp_series(v, t, len, len, wp); } else { arb_set(f, h); arb_one(f + 1); rflen = FLINT_MIN(len, r + 1); _arb_poly_rising_ui_series(t, f, FLINT_MIN(2, len), r, rflen, wp); arb_add_ui(f, h, r, wp); _arb_poly_gamma_stirling_eval(v, f, n, len, wp); _arb_vec_neg(v, v, len); _arb_poly_exp_series(u, v, len, len, wp); _arb_poly_mullow(v, u, len, t, rflen, len, wp); } } } /* compose with nonconstant part */ arb_zero(t); _arb_vec_set(t + 1, h + 1, hlen - 1); _arb_poly_compose_series(res, v, len, t, hlen, len, prec); arb_clear(f); arb_clear(f + 1); _arb_vec_clear(t, len); _arb_vec_clear(u, len); _arb_vec_clear(v, len); }
void _arb_poly_lgamma_series(arb_ptr res, arb_srcptr h, slong hlen, slong len, slong prec) { int reflect; slong r, n, wp; arb_t zr; arb_ptr t, u; if (!arb_is_positive(h)) { _arb_vec_indeterminate(res, len); return; } hlen = FLINT_MIN(hlen, len); wp = prec + FLINT_BIT_COUNT(prec); t = _arb_vec_init(len); u = _arb_vec_init(len); arb_init(zr); /* use zeta values at small integers */ if (arb_is_int(h) && (arf_cmpabs_ui(arb_midref(h), prec / 2) < 0)) { r = arf_get_si(arb_midref(h), ARF_RND_DOWN); if (r <= 0) { _arb_vec_indeterminate(res, len); goto cleanup; } else { _arb_poly_lgamma_series_at_one(u, len, wp); if (r != 1) { arb_one(zr); _log_rising_ui_series(t, zr, r - 1, len, wp); _arb_vec_add(u, u, t, len, wp); } } } else if (len <= 2) { arb_lgamma(u, h, wp); if (len == 2) arb_digamma(u + 1, h, wp); } else { /* otherwise use Stirling series */ arb_gamma_stirling_choose_param(&reflect, &r, &n, h, 0, 0, wp); arb_add_ui(zr, h, r, wp); _arb_poly_gamma_stirling_eval(u, zr, n, len, wp); if (r != 0) { _log_rising_ui_series(t, h, r, len, wp); _arb_vec_sub(u, u, t, len, wp); } } /* compose with nonconstant part */ arb_zero(t); _arb_vec_set(t + 1, h + 1, hlen - 1); _arb_poly_compose_series(res, u, len, t, hlen, len, prec); cleanup: arb_clear(zr); _arb_vec_clear(t, len); _arb_vec_clear(u, len); }