74 lines
2.1 KiB
C
74 lines
2.1 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 "fmpq_mat.h"
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void fmpq_mat_det(fmpq_t det, const fmpq_mat_t mat)
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{
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slong n = mat->r;
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if (n == 0)
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{
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fmpq_set_si(det, WORD(1), WORD(1));
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return;
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}
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else if (n == 1)
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{
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fmpq_set(det, fmpq_mat_entry(mat, 0, 0));
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}
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else if (n == 2)
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{
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fmpq_t t;
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fmpq_init(t);
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fmpq_mul(t, fmpq_mat_entry(mat, 0, 0), fmpq_mat_entry(mat, 1, 1));
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fmpq_submul(t, fmpq_mat_entry(mat, 0, 1), fmpq_mat_entry(mat, 1, 0));
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fmpq_set(det, t);
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fmpq_clear(t);
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}
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else
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{
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fmpz_mat_t num;
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fmpz * den;
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slong i;
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fmpz_mat_init(num, mat->r, mat->c);
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den = _fmpz_vec_init(mat->r);
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fmpq_mat_get_fmpz_mat_rowwise(num, den, mat);
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fmpz_mat_det(&det->num, num);
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fmpz_one(&det->den);
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for (i = 0; i < mat->r; i++)
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fmpz_mul(&det->den, &det->den, den + i);
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fmpq_canonicalise(det);
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fmpz_mat_clear(num);
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_fmpz_vec_clear(den, mat->r);
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}
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}
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