70 lines
2.0 KiB
C
70 lines
2.0 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, 2010 Sebastian Pancratz
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Copyright (C) 2009, 2008 William Hart
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******************************************************************************/
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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_mod_poly.h"
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void
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_fmpz_mod_poly_shift_right(fmpz * res, const fmpz * poly, slong len, slong n)
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{
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slong i;
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/* Copy in forward order to avoid writing over unshifted coefficients */
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if (res != poly)
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{
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for (i = 0; i < len - n; i++)
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fmpz_set(res + i, poly + n + i);
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}
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else
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{
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for (i = 0; i < len - n; i++)
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fmpz_swap(res + i, res + n + i);
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}
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}
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void
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fmpz_mod_poly_shift_right(fmpz_mod_poly_t res, const fmpz_mod_poly_t poly, slong n)
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{
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if (n == 0)
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{
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fmpz_mod_poly_set(res, poly);
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return;
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}
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if (poly->length <= n)
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{
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fmpz_mod_poly_zero(res);
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return;
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}
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fmpz_mod_poly_fit_length(res, poly->length - n);
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_fmpz_mod_poly_shift_right(res->coeffs, poly->coeffs, poly->length, n);
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_fmpz_mod_poly_set_length(res, poly->length - n);
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}
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