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#include <stdlib.h>
#include <math.h>
/* Generate gaussian random float with mean=0 and std_dev=1 */
float gran_()
{
float fac,rsq,v1,v2;
static float gset;
static int iset;
if(iset){
/* Already got one */
iset = 0;
return gset;
}
/* Generate two evenly distributed numbers between -1 and +1
* that are inside the unit circle
*/
do {
v1 = 2.0 * (float)rand() / RAND_MAX - 1;
v2 = 2.0 * (float)rand() / RAND_MAX - 1;
rsq = v1*v1 + v2*v2;
} while(rsq >= 1.0 || rsq == 0.0);
fac = sqrt(-2.0*log(rsq)/rsq);
gset = v1*fac;
iset++;
return v2*fac;
}
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