Method nrandf

source/core/StarRandom.cpp:149–159

normal distribution via Box-Muller

// normal distribution via Box-Muller
float RandomSource::nrandf(float stddev, float mean) {
  float rand1, rand2, distSqr;
  do {
    rand1 = 2 * randf() - 1;
    rand2 = 2 * randf() - 1;
    distSqr = rand1 * rand1 + rand2 * rand2;
  } while (distSqr >= 1);

  float mapping = std::sqrt(-2 * std::log(distSqr) / distSqr);
  return (rand1 * mapping * stddev + mean);
}

double RandomSource::nrandd(double stddev, double mean) {
  double rand1, rand2, distSqr;