50 lines
1.6 KiB
C
50 lines
1.6 KiB
C
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/*=============================================================================
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This file is part of FLINT.
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FLINT 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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FLINT 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 FLINT; 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) 2011 Fredrik Johansson
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******************************************************************************/
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#include "fmpq.h"
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void fmpq_div_2exp(fmpq_t res, const fmpq_t x, mp_bitcnt_t exp)
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{
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if (fmpq_is_zero(x) || exp == 0)
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{
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fmpq_set(res, x);
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}
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else
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{
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mp_bitcnt_t v = fmpz_val2(fmpq_numref(x));
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if (exp <= v)
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{
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fmpz_fdiv_q_2exp(fmpq_numref(res), fmpq_numref(x), exp);
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fmpz_set(fmpq_denref(res), fmpq_denref(x));
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}
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else
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{
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fmpz_fdiv_q_2exp(fmpq_numref(res), fmpq_numref(x), v);
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fmpz_mul_2exp(fmpq_denref(res), fmpq_denref(x), exp - v);
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}
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}
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}
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