mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
59 lines
2 KiB
C
59 lines
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 "elefun.h"
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static __inline__ void
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elefun_exp_fmpr_via_mpfr(fmprb_t z, const fmpr_t x, long prec)
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{
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long r;
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r = fmpr_exp(fmprb_midref(z), x, prec, FMPR_RND_DOWN);
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fmpr_set_error_result(fmprb_radref(z), fmprb_midref(z), r);
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}
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void
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elefun_exp_via_mpfr(fmprb_t z, const fmprb_t x, long prec)
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{
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if (fmprb_is_exact(x))
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{
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elefun_exp_fmpr_via_mpfr(z, fmprb_midref(x), prec);
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}
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else
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{
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/* exp(a+b) - exp(a) = exp(a) * (exp(b)-1) <= b * exp(a+b) */
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fmpr_t t;
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fmpr_init(t);
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fmpr_add(t, fmprb_midref(x), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_CEIL);
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fmpr_exp(t, t, FMPRB_RAD_PREC, FMPR_RND_UP);
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fmpr_mul(t, t, fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_UP);
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elefun_exp_fmpr_via_mpfr(z, fmprb_midref(x), prec);
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fmpr_add(fmprb_radref(z), fmprb_radref(z), t, FMPRB_RAD_PREC, FMPR_RND_UP);
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fmpr_clear(t);
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}
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}
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