mirror of
https://github.com/VK3FNG/soundmodem.git
synced 2025-12-06 03:01:59 +01:00
42 lines
1.2 KiB
C
42 lines
1.2 KiB
C
|
/*
|
||
|
|
* 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);
|
||
|
|
}
|
||
|
|
|