mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
79 lines
2.2 KiB
C
79 lines
2.2 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 "fmprb.h"
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#include "gamma.h"
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void
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fmprb_gamma_fmpq(fmprb_t y, const fmpq_t x, long prec)
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{
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fmpz p, q;
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p = *fmpq_numref(x);
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q = *fmpq_denref(x);
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if ((q == 1 || q == 2 || q == 3 || q == 4 || q == 6) && !COEFF_IS_MPZ(p))
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{
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if (q == 1)
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{
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if (p <= 0)
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{
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fmpr_nan(fmprb_midref(y));
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fmpr_pos_inf(fmprb_radref(y));
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return;
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}
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if (p < 1200 || 1.44265 * (p*log(p) - p) < 15.0 * prec)
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{
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fmpz_t t;
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fmpz_init(t);
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fmpz_fac_ui(t, p - 1);
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fmprb_set_round_fmpz(y, t, prec);
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fmpz_clear(t);
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return;
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}
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}
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p = FLINT_ABS(p);
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if (p < q * 500.0 || p < q * (500.0 + 0.1 * prec * sqrt(prec)))
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{
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gamma_fmpq_outward(y, x, prec);
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return;
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}
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}
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gamma_fmpq_stirling(y, x, prec);
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}
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void
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fmprb_gamma_fmpz(fmprb_t y, const fmpz_t x, long prec)
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{
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fmpq_t t;
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*fmpq_numref(t) = *x;
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*fmpq_denref(t) = 1L;
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fmprb_gamma_fmpq(y, t, prec);
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}
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