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/*
* Matrix operations library
*
* Copyright (C) 1999-2000
* Thomas Sailer, <sailer@ife.ee.ethz.ch>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mat.h"
#include <stdlib.h>
/*
* Approximation of a normally distributed random number generator
* with unit variance
*
* division factor: randommax * sqrt(nrand / 12)
* with nrand = 16 and randommax = 0x1000
*/
float randn(void)
{
int sum = 0, i;
for (i = 0; i < 16; i++)
sum += random() & 0xfff;
return (sum - 0x8000) * (1.0 / 4729.7);
}
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