133 lines
3.6 KiB
C
133 lines
3.6 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 William Hart
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Copyright (C) 2013 Martin Lee
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******************************************************************************/
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#undef ulong
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#define ulong ulongxx/* interferes with system includes */
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#include <stdlib.h>
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#undef ulong
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#include <gmp.h>
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#define ulong mp_limb_t
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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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#include "ulong_extras.h"
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void _nmod_poly_divrem_newton_n_preinv (mp_ptr Q, mp_ptr R, mp_srcptr A,
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slong lenA, mp_srcptr B, slong lenB,
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mp_srcptr Binv, slong lenBinv, nmod_t mod)
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{
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const slong lenQ = lenA - lenB + 1;
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if (lenA == lenB + 1)
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{
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_nmod_poly_divrem_q1 (Q, R, A, lenA, B, lenB, mod);
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return;
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}
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_nmod_poly_div_newton_n_preinv (Q, A, lenA, B, lenB, Binv, lenBinv, mod);
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if (lenB > 1)
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{
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if (lenQ >= lenB - 1)
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_nmod_poly_mullow(R, Q, lenQ, B, lenB - 1, lenB - 1, mod);
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else
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_nmod_poly_mullow(R, B, lenB - 1, Q, lenQ, lenB - 1, mod);
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_nmod_vec_sub(R, A, R, lenB - 1, mod);
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}
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}
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void nmod_poly_divrem_newton_n_preinv(nmod_poly_t Q, nmod_poly_t R,
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const nmod_poly_t A, const nmod_poly_t B,
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const nmod_poly_t Binv)
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{
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const slong lenA = A->length, lenB = B->length, lenBinv = Binv->length;
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mp_ptr q, r;
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if (lenB == 0)
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{
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flint_printf("Exception (nmod_poly_divrem_newton_n_preinv). Division by zero.\n");
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abort();
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}
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if (lenA < lenB)
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{
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nmod_poly_set(R, A);
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nmod_poly_zero(Q);
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return;
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}
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if (lenA > 2 * lenB - 2)
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{
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flint_printf ("Exception (nmod_poly_divrem_newton_n_preinv).\n");
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}
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if (Q == A || Q == B || Q == Binv)
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{
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q = _nmod_vec_init(lenA - lenB + 1);
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}
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else
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{
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nmod_poly_fit_length(Q, lenA - lenB + 1);
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q = Q->coeffs;
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}
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if (R == A || R == B || R == Binv)
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{
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r = _nmod_vec_init(lenB - 1);
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}
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else
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{
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nmod_poly_fit_length(R, lenB - 1);
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r = R->coeffs;
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}
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_nmod_poly_divrem_newton_n_preinv (q, r, A->coeffs, lenA,
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B->coeffs, lenB, Binv->coeffs,
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lenBinv, B->mod);
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if (Q == A || Q == B || Q == Binv)
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{
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_nmod_vec_clear(Q->coeffs);
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Q->coeffs = q;
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Q->alloc = lenA - lenB + 1;
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}
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if (R == A || R == B || R == Binv)
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{
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_nmod_vec_clear(R->coeffs);
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R->coeffs = r;
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R->alloc = lenB - 1;
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}
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Q->length = lenA - lenB + 1;
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R->length = lenB - 1;
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_nmod_poly_normalise(R);
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}
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