sample method

Implementation

@override
double sample({Random? random}) {
  const normal = NormalDistribution.standard();
  const uniform = UniformDistribution.standard();
  final correctedShape = shape < 1 ? shape + 1 : shape;
  double u, v, x;
  final a1 = correctedShape - 1 / 3;
  final a2 = 1 / sqrt(9 * a1);
  do {
    do {
      x = normal.sample(random: random);
      v = 1 + a2 * x;
    } while (v <= 0);
    v = v * v * v;
    u = uniform.sample(random: random);
  } while (u > 1 - 0.331 * pow(x, 4) &&
      log(u) > 0.5 * x * x + a1 * (1 - v + log(v)));
  if (shape == correctedShape) {
    return a1 * v * scale;
  }
  do {
    u = uniform.sample(random: random);
  } while (u == 0);
  return pow(u, 1 / shape) * a1 * v * scale;
}