83 lines
2.2 KiB
C
83 lines
2.2 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 Fredrik Johansson
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******************************************************************************/
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#include "fmpz_mat.h"
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#include "fmpq.h"
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void
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fmpz_mat_det_divisor(fmpz_t d, const fmpz_mat_t A)
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{
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fmpz_mat_t X, B;
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fmpz_t t, u, v, mod;
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slong i, n;
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int success;
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n = A->r;
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fmpz_mat_init(B, n, 1);
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fmpz_mat_init(X, n, 1);
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fmpz_init(t);
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fmpz_init(u);
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fmpz_init(v);
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fmpz_init(mod);
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/* Create a "random" vector */
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for (i = 0; i < n; i++)
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{
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fmpz_set_si(fmpz_mat_entry(B, i, 0), 2*(i % 2) - 1);
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}
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success = fmpz_mat_solve_dixon(X, mod, A, B);
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if (success)
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{
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fmpz_one(d);
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for (i = 0; i < n; i++)
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{
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fmpz_mul(t, d, fmpz_mat_entry(X, i, 0));
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fmpz_fdiv_qr(u, t, t, mod);
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if (!_fmpq_reconstruct_fmpz(u, v, t, mod))
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{
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flint_printf("Exception (fmpz_mat_det_divisor): "
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"Rational reconstruction failed.\n");
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abort();
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}
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fmpz_mul(d, v, d);
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}
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}
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else
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{
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fmpz_zero(d);
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}
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fmpz_mat_clear(B);
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fmpz_mat_clear(X);
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fmpz_clear(t);
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fmpz_clear(u);
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fmpz_clear(v);
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fmpz_clear(mod);
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}
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