#include "random.h"
#include <math.h>

double randn(void)
{
    /* Generates a random number from a normal distribution using the
     * Box-Muller transform. */
    double u1, u2;

    u1 = genrand_real1();
    u2 = genrand_real1();

    return sqrt(-2*log(u1))*cos(2*M_PI*u2);
}