87 lines
2.5 KiB
C
87 lines
2.5 KiB
C
/*=============================================================================
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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) 2010 Sebastian Pancratz
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******************************************************************************/
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#include <limits.h>
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#include <gmp.h>
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#include "flint.h"
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#include "fmpz.h"
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#include "fmpz_vec.h"
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#include "fmpq_poly.h"
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void _fmpq_poly_scalar_mul_si(fmpz * rpoly, fmpz_t rden,
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const fmpz * poly, const fmpz_t den, slong len,
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slong c)
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{
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fmpz_t gcd; /* GCD( den, c ) */
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if (c == 0)
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{
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_fmpz_vec_zero(rpoly, len);
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fmpz_one(rden);
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return;
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}
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fmpz_init(gcd);
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fmpz_set_si(gcd, c);
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fmpz_gcd(gcd, gcd, den);
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if (*gcd == WORD(1))
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{
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_fmpz_vec_scalar_mul_si(rpoly, poly, len, c);
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fmpz_set(rden, den);
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}
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else
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{
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if (c > WORD_MIN || fmpz_cmp_ui(gcd, - (ulong) WORD_MIN))
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{
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slong g = fmpz_get_si(gcd);
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_fmpz_vec_scalar_mul_si(rpoly, poly, len, c / g);
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fmpz_divexact_si(rden, den, g);
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}
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else
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{
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_fmpz_vec_neg(rpoly, poly, len);
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fmpz_divexact_ui(rden, den, - (ulong) WORD_MIN);
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}
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}
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fmpz_clear(gcd);
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}
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void fmpq_poly_scalar_mul_si(fmpq_poly_t rop, const fmpq_poly_t op, slong c)
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{
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if (c == 0 || fmpq_poly_is_zero(op))
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{
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fmpq_poly_zero(rop);
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return;
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}
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fmpq_poly_fit_length(rop, op->length);
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_fmpq_poly_set_length(rop, op->length);
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_fmpq_poly_scalar_mul_si(rop->coeffs, rop->den,
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op->coeffs, op->den, op->length, c);
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}
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