using System; using NUnit.Framework; using MLAgents.InferenceBrain.Utils; namespace MLAgents.Tests { public class RandomNormalTest { private const float k_FirstValue = -1.19580f; private const float k_SecondValue = -0.97345f; private const double k_Epsilon = 0.0001; [Test] public void RandomNormalTestTwoDouble() { var rn = new RandomNormal(2018); Assert.AreEqual(k_FirstValue, rn.NextDouble(), k_Epsilon); Assert.AreEqual(k_SecondValue, rn.NextDouble(), k_Epsilon); } [Test] public void RandomNormalTestWithMean() { var rn = new RandomNormal(2018, 5.0f); Assert.AreEqual(k_FirstValue + 5.0, rn.NextDouble(), k_Epsilon); Assert.AreEqual(k_SecondValue + 5.0, rn.NextDouble(), k_Epsilon); } [Test] public void RandomNormalTestWithStddev() { var rn = new RandomNormal(2018, 0.0f, 4.2f); Assert.AreEqual(k_FirstValue * 4.2, rn.NextDouble(), k_Epsilon); Assert.AreEqual(k_SecondValue * 4.2, rn.NextDouble(), k_Epsilon); } [Test] public void RandomNormalTestWithMeanStddev() { const float mean = -3.2f; const float stddev = 2.2f; var rn = new RandomNormal(2018, mean, stddev); Assert.AreEqual(k_FirstValue * stddev + mean, rn.NextDouble(), k_Epsilon); Assert.AreEqual(k_SecondValue * stddev + mean, rn.NextDouble(), k_Epsilon); } [Test] public void RandomNormalTestDistribution() { const float mean = -3.2f; const float stddev = 2.2f; var rn = new RandomNormal(2018, mean, stddev); const int numSamples = 100000; // Adapted from https://www.johndcook.com/blog/standard_deviation/ // Computes stddev and mean without losing precision double oldM = 0.0, newM = 0.0, oldS = 0.0, newS = 0.0; for (var i = 0; i < numSamples; i++) { var x = rn.NextDouble(); if (i == 0) { oldM = newM = x; oldS = 0.0; } else { newM = oldM + (x - oldM) / i; newS = oldS + (x - oldM) * (x - newM); // set up for next iteration oldM = newM; oldS = newS; } } var sampleMean = newM; var sampleVariance = newS / (numSamples - 1); var sampleStddev = Math.Sqrt(sampleVariance); // Note a larger epsilon here. We could get closer to the true values with more samples. Assert.AreEqual(mean, sampleMean, 0.01); Assert.AreEqual(stddev, sampleStddev, 0.01); } } }