100 lines
2.6 KiB
C
100 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) 2008, 2009 William Hart
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Copyright (C) 2010 Sebastian Pancratz
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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 "fmpz.h"
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#include "fmpz_vec.h"
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#include "fmpz_poly.h"
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void
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_fmpz_poly_rem_basecase(fmpz * R, const fmpz * A, slong lenA,
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const fmpz * B, slong lenB)
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{
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const fmpz * leadB = B + (lenB - 1);
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fmpz_t q;
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fmpz_init(q);
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if (R != A)
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_fmpz_vec_set(R, A, lenA);
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for ( ; lenA >= lenB; lenA--)
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{
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if (fmpz_cmpabs(R + lenA - 1, leadB) >= 0)
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{
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fmpz_fdiv_q(q, R + lenA - 1, leadB);
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_fmpz_vec_scalar_submul_fmpz(R + lenA - lenB, B, lenB, q);
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}
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}
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fmpz_clear(q);
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}
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void
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fmpz_poly_rem_basecase(fmpz_poly_t R,
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const fmpz_poly_t A, const fmpz_poly_t B)
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{
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slong lenr;
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fmpz *r;
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if (B->length == 0)
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{
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flint_printf("Exception (fmpz_poly_rem_basecase). Division by zero.\n");
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abort();
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}
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if (A->length < B->length)
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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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lenr = A->length;
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if (R == B)
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r = _fmpz_vec_init(lenr);
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else
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{
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fmpz_poly_fit_length(R, lenr);
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r = R->coeffs;
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}
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_fmpz_poly_rem_basecase(r, A->coeffs, A->length,
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B->coeffs, B->length);
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if (R == B)
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{
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_fmpz_vec_clear(R->coeffs, R->alloc);
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R->coeffs = r;
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R->alloc = lenr;
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R->length = lenr;
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}
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else
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_fmpz_poly_set_length(R, lenr);
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_fmpz_poly_normalise(R);
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}
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