105 lines
2.8 KiB
C
105 lines
2.8 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, 2011 Sebastian Pancratz
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******************************************************************************/
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#include "fmpz_poly_q.h"
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void fmpz_poly_q_scalar_div_si(fmpz_poly_q_t rop, const fmpz_poly_q_t op, slong x)
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{
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fmpz_t cont, fx, gcd;
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if (FLINT_ABS(x) <= 1)
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{
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if (x == 0)
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{
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flint_printf("Exception (fmpz_poly_q_scalar_div_si). Division by zero.\n");
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abort();
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}
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if (x == 1)
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fmpz_poly_q_set(rop, op);
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else
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fmpz_poly_q_neg(rop, op);
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return;
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}
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if (fmpz_poly_q_is_zero(op))
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{
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fmpz_poly_q_zero(rop);
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return;
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}
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fmpz_init(cont);
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fmpz_poly_content(cont, op->num);
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if (fmpz_is_one(cont))
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{
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if (x > 0)
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{
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fmpz_poly_set(rop->num, op->num);
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fmpz_poly_scalar_mul_si(rop->den, op->den, x);
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}
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else
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{
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fmpz_poly_neg(rop->num, op->num);
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fmpz_poly_scalar_mul_ui(rop->den, op->den, - ((ulong) x));
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}
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fmpz_clear(cont);
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return;
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}
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fmpz_init(fx);
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fmpz_init(gcd);
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fmpz_set_si(fx, x);
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fmpz_gcd(gcd, cont, fx);
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if (fmpz_is_one(gcd))
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{
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if (x > 0)
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{
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fmpz_poly_set(rop->num, op->num);
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fmpz_poly_scalar_mul_si(rop->den, op->den, x);
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}
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else
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{
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fmpz_poly_neg(rop->num, op->num);
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fmpz_poly_scalar_mul_ui(rop->den, op->den, - ((ulong) x));
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}
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}
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else
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{
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fmpz_poly_scalar_divexact_fmpz(rop->num, op->num, gcd);
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fmpz_divexact(fx, fx, gcd);
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fmpz_poly_scalar_mul_fmpz(rop->den, op->den, fx);
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if (x < 0)
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{
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fmpz_poly_neg(rop->num, rop->num);
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fmpz_poly_neg(rop->den, rop->den);
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}
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}
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fmpz_clear(cont);
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fmpz_clear(fx);
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fmpz_clear(gcd);
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}
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