mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
/*=============================================================================
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This file is part of ARB.
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ARB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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ARB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ARB; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2013 Fredrik Johansson
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******************************************************************************/
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#include "gamma.h"
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#include "fmprb_poly.h"
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static void
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bsplit_step(fmpcb_t y, fmprb_srcptr poly, ulong step, const fmpcb_t x, ulong a, ulong b, long prec)
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{
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if (b - a == step)
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{
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fmpcb_add_ui(y, x, a, prec);
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_fmprb_poly_evaluate_fmpcb(y, poly, step + 1, y, prec);
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}
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else
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{
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ulong m = a + ((b - a) / (2 * step)) * step;
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fmpcb_t t;
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fmpcb_init(t);
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bsplit_step(y, poly, step, x, a, m, prec);
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bsplit_step(t, poly, step, x, m, b, prec);
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fmpcb_mul(y, y, t, prec);
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fmpcb_clear(t);
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}
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}
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void
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gamma_rising_fmpcb_ui_bsplit_rectangular(fmpcb_t y, const fmpcb_t x, ulong n, ulong step, long prec)
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{
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fmpcb_t t, u;
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ulong s1, s2, b;
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long wp;
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wp = FMPR_PREC_ADD(prec, FLINT_BIT_COUNT(n));
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fmpcb_init(t);
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fmpcb_init(u);
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if (step == 0)
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{
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s1 = 2 * sqrt(n);
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s2 = 10 * pow(prec, 0.25);
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step = FLINT_MIN(s1, s2);
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}
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step = FLINT_MAX(step, 1);
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b = (n / step) * step;
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if (b != 0)
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{
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fmprb_ptr poly;
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fmprb_struct xpoly[2];
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poly = _fmprb_vec_init(step + 1);
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fmprb_init(xpoly + 0);
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fmprb_init(xpoly + 1);
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fmprb_one(xpoly + 1);
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_fmprb_poly_rising_ui_series(poly, xpoly, 2, step, step + 1, wp);
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bsplit_step(t, poly, step, x, 0, b, wp);
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_fmprb_vec_clear(poly, step + 1);
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}
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else
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{
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fmpcb_one(t);
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}
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fmpcb_add_ui(u, x, b, wp);
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gamma_rising_fmpcb_ui_bsplit_simple(u, u, n - b, wp);
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fmpcb_mul(y, t, u, prec);
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fmpcb_clear(t);
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fmpcb_clear(u);
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}
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