public void PerformsDnaMutation()
{
// Arrange
const int nInputs = 2;
const int nOutputs = 2;
const int outputLayerActivationIndex = 3;
int[] hiddenLayers = new int[] { 7 };
Dna originalDna = Dna.GenerateRandomDnaEncoding(nInputs, hiddenLayers, nOutputs, (ActivationType)outputLayerActivationIndex, true);
float weightMutationPrevalence = 0.2f;
// Act
Dna mutatedDna = Dna.CloneAndMutate(originalDna, DnaHeritage.MutatedElite, weightMutationPrevalence, 0.8f);
// Assert
CheckDnaIsNotReferentiallyEqual(originalDna, mutatedDna);
// Structure
mutatedDna.OutputsPerLayer.Should().Equal(originalDna.OutputsPerLayer);
mutatedDna.Heritage.Should().Be(DnaHeritage.MutatedElite);
// Weights
mutatedDna.WeightsAndBiases.Should().NotEqual(originalDna.WeightsAndBiases);
mutatedDna.WeightsAndBiases.Should().HaveCount(originalDna.WeightsAndBiases.Count);
List <double> mutatedWeights = new List <double>();
for (int i = 0; i < originalDna.WeightsAndBiases.Count; i++)
{
if (originalDna.WeightsAndBiases[i] != mutatedDna.WeightsAndBiases[i])
{
mutatedWeights.Add(mutatedDna.WeightsAndBiases[i]);
}
}
mutatedWeights.Should().HaveCount(Mathf.CeilToInt(weightMutationPrevalence * originalDna.WeightsAndBiases.Count));
// Activation
mutatedDna.ActivationIndexes.Should().NotEqual(originalDna.ActivationIndexes);
mutatedDna.ActivationIndexes.Should().HaveCount(originalDna.ActivationIndexes.Count);
int indexOfOutputLayerActivation = originalDna.ActivationIndexes.Count - nOutputs;
mutatedDna.ActivationIndexes.Skip(indexOfOutputLayerActivation)
.Should().Equal(originalDna.ActivationIndexes.Skip(indexOfOutputLayerActivation), "preserves output layer activation functions");
}
