101 lines
3.1 KiB
C
101 lines
3.1 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) 2010 William Hart
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******************************************************************************/
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#include <stdlib.h>
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#include <gmp.h>
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#include "flint.h"
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#include "nmod_vec.h"
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#include "nmod_poly.h"
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void _nmod_poly_mullow(mp_ptr res, mp_srcptr poly1, slong len1,
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mp_srcptr poly2, slong len2, slong n, nmod_t mod)
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{
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slong bits, bits2;
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if (len1 + len2 <= 6 || n <= 6)
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{
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_nmod_poly_mullow_classical(res, poly1, len1, poly2, len2, n, mod);
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return;
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}
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bits = FLINT_BITS - (slong) mod.norm;
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bits2 = FLINT_BIT_COUNT(len1);
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if (2 * bits + bits2 <= FLINT_BITS && len1 + len2 < 16)
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_nmod_poly_mullow_classical(res, poly1, len1, poly2, len2, n, mod);
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else
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_nmod_poly_mullow_KS(res, poly1, len1, poly2, len2, 0, n, mod);
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}
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void nmod_poly_mullow(nmod_poly_t res,
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const nmod_poly_t poly1, const nmod_poly_t poly2, slong trunc)
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{
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slong len1, len2, len_out;
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len1 = poly1->length;
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len2 = poly2->length;
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len_out = poly1->length + poly2->length - 1;
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if (trunc > len_out)
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trunc = len_out;
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if (len1 == 0 || len2 == 0 || trunc == 0)
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{
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nmod_poly_zero(res);
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return;
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}
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if (res == poly1 || res == poly2)
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{
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nmod_poly_t temp;
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nmod_poly_init2(temp, poly1->mod.n, trunc);
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if (len1 >= len2)
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_nmod_poly_mullow(temp->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, trunc, poly1->mod);
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else
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_nmod_poly_mullow(temp->coeffs, poly2->coeffs, len2,
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poly1->coeffs, len1, trunc, poly1->mod);
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nmod_poly_swap(temp, res);
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nmod_poly_clear(temp);
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} else
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{
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nmod_poly_fit_length(res, trunc);
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if (len1 >= len2)
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_nmod_poly_mullow(res->coeffs, poly1->coeffs, len1,
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poly2->coeffs, len2, trunc, poly1->mod);
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else
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_nmod_poly_mullow(res->coeffs, poly2->coeffs, len2,
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poly1->coeffs, len1, trunc, poly1->mod);
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}
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res->length = trunc;
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_nmod_poly_normalise(res);
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}
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