float
randomGauss()
{
  static int iset = 0;
  static float gset;
  float fac, rsq, v1, v2;
  if(iset == 0) {
    do {
      v1 = 2.0 * rand()/(RAND_MAX+1.0) - 1.0;
      v2 = 2.0 * rand()/(RAND_MAX+1.0) - 1.0;         
      rsq = v1*v1 + v2*v2;
    } while(rsq >= 1.0 || rsq == 0.0);
    fac = sqrt(-2.0*log(rsq)/rsq);
    gset = v1*fac;
    iset = 1;
    return v2*fac;
  }
  else {
    iset = 0;
    return gset;
  }
}