99 lines
2.6 KiB
C
99 lines
2.6 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) 2013 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_poly.h"
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void _fmpz_poly_rem_powers_precomp(fmpz * A, slong m,
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const fmpz * B, slong n, fmpz ** const powers)
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{
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slong i;
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fmpz * prod;
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if (m >= 2*n)
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{
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_fmpz_poly_rem_powers_precomp(A + n, m - n, B, n, powers);
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m = 2*n - 1;
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while (m && fmpz_is_zero(A + m - 1)) m--;
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}
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if (m < n)
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return;
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prod = _fmpz_vec_init(n - 1);
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for (i = n - 1; i < m; i++)
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{
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_fmpz_vec_scalar_mul_fmpz(prod, powers[i], n - 1, A + i);
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_fmpz_poly_add(A, A, n - 1, prod, n - 1);
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}
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_fmpz_vec_clear(prod, n - 1);
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}
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void
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fmpz_poly_rem_powers_precomp(fmpz_poly_t R, const fmpz_poly_t A,
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const fmpz_poly_t B, const fmpz_poly_powers_precomp_t B_inv)
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{
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fmpz_poly_t tR;
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fmpz *r;
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slong len1 = A->length, len2 = B->length;
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if (len1 < len2)
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{
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fmpz_poly_set(R, A);
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return;
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}
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if (R == B)
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{
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fmpz_poly_init2(tR, len1);
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r = tR->coeffs;
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}
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else
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{
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fmpz_poly_fit_length(R, len1);
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r = R->coeffs;
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}
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if (R == B || R != A)
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_fmpz_vec_set(r, A->coeffs, len1);
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_fmpz_poly_rem_powers_precomp(r, len1, B->coeffs, len2, B_inv->powers);
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if (R == B)
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{
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_fmpz_poly_set_length(tR, len2 - 1);
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fmpz_poly_swap(tR, R);
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fmpz_poly_clear(tR);
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}
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else
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_fmpz_poly_set_length(R, len2 - 1);
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_fmpz_poly_normalise(R);
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}
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