71 lines
2.0 KiB
C
71 lines
2.0 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) 2010 Fredrik Johansson
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******************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include "flint.h"
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#include "ulong_extras.h"
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#include "nmod_vec.h"
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#include "nmod_mat.h"
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int nmod_mat_inv(nmod_mat_t B, const nmod_mat_t A)
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{
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nmod_mat_t I;
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slong i, dim;
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int result;
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dim = A->r;
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switch (dim)
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{
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case 0:
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result = 1;
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break;
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case 1:
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if (nmod_mat_entry(A, 0, 0) == UWORD(0))
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{
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result = 0;
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}
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else
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{
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nmod_mat_entry(B, 0, 0) =
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n_invmod(nmod_mat_entry(A, 0, 0), B->mod.n);
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result = 1;
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}
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break;
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default:
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nmod_mat_init(I, dim, dim, B->mod.n);
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for (i = 0; i < dim; i++)
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nmod_mat_entry(I, i, i) = UWORD(1);
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result = nmod_mat_solve(B, A, I);
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nmod_mat_clear(I);
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}
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return result;
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}
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