mirror of
https://github.com/vale981/arb
synced 2025-03-06 09:51:39 -05:00
84 lines
2.2 KiB
C
84 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) 2012, 2013 Fredrik Johansson
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******************************************************************************/
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#include "fmprb.h"
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void
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fmprb_pow_fmpz_binexp(fmprb_t y, const fmprb_t b, const fmpz_t e, long prec)
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{
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long i, wp, bits;
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if (-2L <= *e && *e <= 2L)
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{
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if (*e == 0L)
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fmprb_one(y);
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else if (*e == 1L)
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fmprb_set_round(y, b, prec);
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else if (*e == -1L)
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fmprb_ui_div(y, 1UL, b, prec);
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else if (*e == 2L)
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fmprb_mul(y, b, b, prec);
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else
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{
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fmprb_ui_div(y, 1UL, b, prec);
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fmprb_mul(y, y, y, prec);
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}
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return;
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}
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if (fmpz_sgn(e) < 0)
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{
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fmpz_t f;
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fmpz_init(f);
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fmpz_neg(f, e);
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fmprb_pow_fmpz_binexp(y, b, f, prec + 2);
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fmprb_ui_div(y, 1UL, y, prec);
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fmpz_clear(f);
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return;
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}
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if (y == b)
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{
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fmprb_t t;
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fmprb_init(t);
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fmprb_set(t, b);
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fmprb_pow_fmpz_binexp(y, t, e, prec);
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fmprb_clear(t);
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return;
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}
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fmprb_set(y, b);
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bits = fmpz_bits(e);
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wp = FMPR_PREC_ADD(prec, bits);
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for (i = bits - 2; i >= 0; i--)
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{
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fmprb_mul(y, y, y, wp);
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if (fmpz_tstbit(e, i))
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fmprb_mul(y, y, b, wp);
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}
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}
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