95 lines
3.0 KiB
C
95 lines
3.0 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 Fredrik Johansson
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******************************************************************************/
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#include <gmp.h>
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#include "flint.h"
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#include "ulong_extras.h"
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#include "nmod_vec.h"
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#include "nmod_poly.h"
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/* Avoid computing every reciprocal */
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#if FLINT64
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#define PROD_TAKE4 UWORD(65535)
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#define PROD_TAKE3 UWORD(2642245)
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#define PROD_TAKE2 UWORD(4294967295)
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#else
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#define PROD_TAKE4 UWORD(255)
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#define PROD_TAKE3 UWORD(1625)
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#define PROD_TAKE2 UWORD(65535)
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#endif
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#define MUL3(xx,yy,zz) n_mulmod2_preinv(xx,\
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n_mulmod2_preinv(yy,zz,mod.n,mod.ninv),mod.n,mod.ninv);
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void _nmod_poly_integral(mp_ptr x_int, mp_srcptr x, slong len, nmod_t mod)
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{
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mp_limb_t r;
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slong k = len - 1;
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while (k > 0)
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{
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if (k > 3 && k < PROD_TAKE4)
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{
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r = n_invmod(k*(k-1)*(k-2)*(k-3), mod.n);
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x_int[k] = MUL3(x[k-1], r, (k-1)*(k-2)*(k-3));
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x_int[k-1] = MUL3(x[k-2], r, k*(k-2)*(k-3));
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x_int[k-2] = MUL3(x[k-3], r, k*(k-1)*(k-3));
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x_int[k-3] = MUL3(x[k-4], r, k*(k-1)*(k-2));
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k -= 4;
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}
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else if (k > 2 && k < PROD_TAKE3)
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{
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r = n_invmod(k*(k-1)*(k-2), mod.n);
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x_int[k] = MUL3(x[k-1], r, (k-1)*(k-2));
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x_int[k-1] = MUL3(x[k-2], r, k*(k-2));
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x_int[k-2] = MUL3(x[k-3], r, k*(k-1));
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k -= 3;
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}
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else if (k > 1 && k < PROD_TAKE2)
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{
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r = n_invmod(k*(k-1), mod.n);
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x_int[k] = MUL3(x[k-1], r, k-1);
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x_int[k-1] = MUL3(x[k-2], r, k);
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k -= 2;
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}
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else
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{
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r = n_invmod(k, mod.n);
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x_int[k] = n_mulmod2_preinv(x[k-1], r, mod.n, mod.ninv);
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k -= 1;
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}
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}
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x_int[0] = UWORD(0);
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}
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void nmod_poly_integral(nmod_poly_t x_int, const nmod_poly_t x)
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{
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nmod_poly_fit_length(x_int, x->length + 1);
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_nmod_poly_integral(x_int->coeffs, x->coeffs, x->length + 1, x->mod);
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x_int->length = x->length + 1;
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_nmod_poly_normalise(x_int);
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}
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