69 lines
2.1 KiB
C
69 lines
2.1 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) 2005-2009 Damien Stehle
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Copyright (C) 2007 David Cade
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Copyright (C) 2010 William Hart
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******************************************************************************/
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#include <math.h>
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#include "fmpz_mat.h"
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void
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fmpz_mat_randajtai(fmpz_mat_t mat, flint_rand_t state, double alpha)
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{
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const slong c = mat->c, r = mat->r, d = r;
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slong i, j;
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fmpz_t tmp;
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if (c != r)
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{
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flint_printf("Exception (fmpz_mat_ajtai): Non-square matrix.\n");
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abort();
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}
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fmpz_init(tmp);
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for (i = 0; i < d; i++)
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{
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mp_bitcnt_t bits = (mp_bitcnt_t) pow((double) (2 * d - i), alpha);
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fmpz_one(tmp);
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fmpz_mul_2exp(tmp, tmp, bits);
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fmpz_sub_ui(tmp, tmp, 1);
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fmpz_randm(mat->rows[i] + i, state, tmp);
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fmpz_add_ui(mat->rows[i] + i, mat->rows[i] + i, 2);
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fmpz_fdiv_q_2exp(mat->rows[i] + i, mat->rows[i] + i, 1);
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for (j = i + 1; j <= d; j++)
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{
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fmpz_randm(mat->rows[j] + i, state, tmp);
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if (n_randint(state, 2))
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fmpz_neg(mat->rows[j] + i, mat->rows[j] + i);
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fmpz_zero(mat->rows[i] + j);
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}
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}
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fmpz_clear(tmp);
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}
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