81 lines
2.3 KiB
C
81 lines
2.3 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) 2010,2011 Fredrik Johansson
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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 "nmod_mat.h"
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#include "nmod_vec.h"
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void
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nmod_mat_solve_triu_classical(nmod_mat_t X, const nmod_mat_t U,
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const nmod_mat_t B, int unit)
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{
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int nlimbs;
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slong i, j, n, m;
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nmod_t mod;
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mp_ptr inv, tmp;
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n = U->r;
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m = B->c;
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mod = U->mod;
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if (!unit)
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{
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inv = _nmod_vec_init(n);
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for (i = 0; i < n; i++)
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inv[i] = n_invmod(nmod_mat_entry(U, i, i), mod.n);
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}
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else
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inv = NULL;
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nlimbs = _nmod_vec_dot_bound_limbs(n, mod);
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tmp = _nmod_vec_init(n);
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for (i = 0; i < m; i++)
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{
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for (j = 0; j < n; j++)
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tmp[j] = nmod_mat_entry(X, j, i);
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for (j = n - 1; j >= 0; j--)
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{
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mp_limb_t s;
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s = _nmod_vec_dot(U->rows[j] + j + 1,
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tmp + j + 1, n - j - 1, mod, nlimbs);
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s = nmod_sub(nmod_mat_entry(B, j, i), s, mod);
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if (!unit)
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s = n_mulmod2_preinv(s, inv[j], mod.n, mod.ninv);
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tmp[j] = s;
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}
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for (j = 0; j < n; j++)
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nmod_mat_entry(X, j, i) = tmp[j];
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}
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_nmod_vec_clear(tmp);
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if (!unit)
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_nmod_vec_clear(inv);
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}
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