64 lines
1.8 KiB
C
64 lines
1.8 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 "fmpz_mat.h"
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void
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fmpz_mat_solve_bound(fmpz_t N, fmpz_t D,
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const fmpz_mat_t A, const fmpz_mat_t B)
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{
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slong i, j, m, n;
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fmpz_t t, u;
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m = B->r;
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n = B->c;
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fmpz_mat_det_bound(D, A);
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fmpz_init(t);
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fmpz_init(u);
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fmpz_zero(t);
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/* Largest column norm of B */
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for (j = 0; j < n; j++)
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{
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fmpz_zero(u);
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for (i = 0; i < m; i++)
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fmpz_addmul(u, fmpz_mat_entry(B, i, j), fmpz_mat_entry(B, i, j));
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if (fmpz_cmp(t, u) < 0)
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fmpz_set(t, u);
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}
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fmpz_sqrtrem(t, u, t);
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if (!fmpz_is_zero(u))
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fmpz_add_ui(t, t, UWORD(1));
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fmpz_mul(N, D, t);
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fmpz_clear(t);
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fmpz_clear(u);
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}
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