79 lines
2.0 KiB
C
79 lines
2.0 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 "fmpz.h"
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#include "fmpz_poly.h"
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void
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_fmpz_poly_div_root(fmpz * Q, const fmpz * A, slong len, const fmpz_t c)
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{
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fmpz_t r, t;
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slong i;
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if (len < 2)
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return;
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fmpz_init(r);
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fmpz_init(t);
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fmpz_set(r, A + len - 1);
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for (i = len - 2; i > 0; i--)
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{
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fmpz_mul(t, r, c);
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fmpz_add(t, t, A + i);
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fmpz_swap(Q + i, r);
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fmpz_swap(r, t);
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}
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fmpz_swap(Q, r);
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fmpz_clear(r);
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fmpz_clear(t);
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}
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void
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fmpz_poly_div_root(fmpz_poly_t Q, const fmpz_poly_t A, const fmpz_t c)
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{
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slong len = A->length;
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if (len <= 1)
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{
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fmpz_poly_zero(Q);
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return;
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}
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if (fmpz_is_zero(c))
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{
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fmpz_poly_shift_right(Q, A, 1);
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return;
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}
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fmpz_poly_fit_length(Q, len - 1);
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_fmpz_poly_div_root(Q->coeffs, A->coeffs, len, c);
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_fmpz_poly_set_length(Q, len - 1);
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}
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