sample method

@override double sample({ Random? random, })

Generates a random sample.

Example

import 'package:calc/calc.dart';

void main() {
  final distribution = NormalDistribution(mean=0.0, variance:1.0);
  final sample = distribution.sample();
}

Implementation

@override
double sample({Random? random}) {
  random ??= Random();

  // Box-Muller polar form algorithm
  var x1 = 0.0;
  var x2 = 0.0;
  var w = 0.0;
  do {
    x1 = (2.0 * random.nextDouble()) - 1.0;
    x2 = (2.0 * random.nextDouble()) - 1.0;
    w = (x1 * x1) + (x2 * x2);
  } while (w >= 1.0);
  final r = x1 * sqrt((-2.0 * log(w)) / w);

  return r * standardDeviation + mean;
}