71 lines
2.1 KiB
C
71 lines
2.1 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) 2011 Sebastian Pancratz
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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_poly.h"
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#include "fmpz_mod_poly.h"
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void _fmpz_mod_poly_derivative(fmpz *res, const fmpz *poly, slong len,
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const fmpz_t p)
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{
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slong j, k = 1;
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for (j = 1; j < len; j++)
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{
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if (k == 0)
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fmpz_zero(res + (j - 1));
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else if (k == 1)
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fmpz_set(res + (j - 1), poly + j);
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else
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{
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fmpz_mul_ui(res + (j - 1), poly + j, k);
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fmpz_mod(res + (j - 1), res + (j - 1), p);
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}
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if (fmpz_equal_ui(p, ++k))
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k = 0;
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}
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}
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void fmpz_mod_poly_derivative(fmpz_mod_poly_t res, const fmpz_mod_poly_t poly)
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{
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const slong len = poly->length;
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if (len < 2)
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{
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fmpz_mod_poly_zero(res);
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}
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else
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{
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fmpz_mod_poly_fit_length(res, len - 1);
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_fmpz_mod_poly_derivative(res->coeffs, poly->coeffs, len, &(res->p));
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_fmpz_mod_poly_set_length(res, len - 1);
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_fmpz_mod_poly_normalise(res);
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}
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}
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