public void Train_TrainsTheNetwork()
{
//// SETUP
const int NumEpochs = 3;
const float LearningRate = 0.1f;
const float Momentum = 0.9f;
const double FinalError = 99.99d;
var inputs = new[] { new[] { 1.0d, 2.0d }, new[] { 3.0d, 4.0d } };
var ideals = new[] { new[] { 5.0d, 6.0d }, new[] { 7.0d, 8.0d } };
var outputs = new[] { new[] { 3.5d, 5.5d }, new[] { 7.5d, 9.5d } };
var overallErrors = new[]
{
new[] { ideals[0][0] - outputs[0][0], ideals[0][1] - outputs[0][1] },
new[] { ideals[1][0] - outputs[1][0], ideals[1][1] - outputs[1][1] }
};
var finalErrors = new[] { new[] { 1.5d, 2.5d }, new[] { 3.5d, 4.5d } };
var mockErrorCalc = new Mock<IErrorCalculator>();
mockErrorCalc.Setup(mock => mock.Calculate()).Returns(FinalError);
// Create 2 input nodes and 2 output nodes.
var mockInputNode1 = new Mock<ISupervisedLearnerNode>();
var mockInputNode2 = new Mock<ISupervisedLearnerNode>();
var mockOutputNode1 = new Mock<ISupervisedLearnerNode>();
var mockOutputNode2 = new Mock<ISupervisedLearnerNode>();
// Program nodes to report input/output sizes.
mockInputNode1.SetupGet(mock => mock.InputSize).Returns(1);
mockInputNode2.SetupGet(mock => mock.InputSize).Returns(1);
mockOutputNode1.SetupGet(mock => mock.OutputSize).Returns(1);
mockOutputNode2.SetupGet(mock => mock.OutputSize).Returns(1);
// Program output nodes to return output values based on inputs.
mockInputNode1.Setup(mock => mock.Fire(new[] { inputs[0][0] })).Callback(() => mockOutputNode1.SetupGet(mock => mock.CachedOutputs).Returns(new[] { outputs[0][0] }));
mockInputNode2.Setup(mock => mock.Fire(new[] { inputs[0][1] })).Callback(() => mockOutputNode2.SetupGet(mock => mock.CachedOutputs).Returns(new[] { outputs[0][1] }));
mockInputNode1.Setup(mock => mock.Fire(new[] { inputs[1][0] })).Callback(() => mockOutputNode1.SetupGet(mock => mock.CachedOutputs).Returns(new[] { outputs[1][0] }));
mockInputNode2.Setup(mock => mock.Fire(new[] { inputs[1][1] })).Callback(() => mockOutputNode2.SetupGet(mock => mock.CachedOutputs).Returns(new[] { outputs[1][1] }));
// Program input nodes to return final error based on overal errors.
mockOutputNode1.Setup(mock => mock.CalculateError(overallErrors[0][0])).Callback(
() => mockInputNode1.SetupGet(mock => mock.CachedErrors).Returns(new[] { finalErrors[0][0] }));
mockOutputNode1.Setup(mock => mock.CalculateError(overallErrors[1][0])).Callback(
() => mockInputNode1.SetupGet(mock => mock.CachedErrors).Returns(new[] { finalErrors[1][0] }));
mockOutputNode2.Setup(mock => mock.CalculateError(overallErrors[0][1])).Callback(
() => mockInputNode2.SetupGet(mock => mock.CachedErrors).Returns(new[] { finalErrors[0][1] }));
mockOutputNode2.Setup(mock => mock.CalculateError(overallErrors[1][1])).Callback(
() => mockInputNode2.SetupGet(mock => mock.CachedErrors).Returns(new[] { finalErrors[1][1] }));
// Create the network
var network = new BackpropagationNetwork(mockErrorCalc.Object);
network.AddInputNode(mockInputNode1.Object);
network.AddInputNode(mockInputNode2.Object);
network.AddOutputNode(mockOutputNode1.Object);
network.AddOutputNode(mockOutputNode2.Object);
// Execute
var actualError = network.Train(NumEpochs, LearningRate, Momentum, inputs, ideals);
//// Verify
// Use of error calculator
mockErrorCalc.Verify(mock => mock.Reset(), Times.Exactly(NumEpochs));
mockErrorCalc.Verify(mock => mock.AddToErrorCalc(overallErrors[0]), Times.Exactly(NumEpochs));
mockErrorCalc.Verify(mock => mock.AddToErrorCalc(overallErrors[1]), Times.Exactly(NumEpochs));
mockErrorCalc.Verify(mock => mock.Calculate(), Times.Once());
// Use of input nodes
mockInputNode1.Verify(mock => mock.Fire(new[] { inputs[0][0] }), Times.Exactly(NumEpochs));
mockInputNode1.Verify(mock => mock.Fire(new[] { inputs[1][0] }), Times.Exactly(NumEpochs));
mockInputNode2.Verify(mock => mock.Fire(new[] { inputs[0][1] }), Times.Exactly(NumEpochs));
mockInputNode2.Verify(mock => mock.Fire(new[] { inputs[1][1] }), Times.Exactly(NumEpochs));
mockInputNode1.Verify(mock => mock.ClearCachedErrors(), Times.Exactly(NumEpochs * inputs.Length));
mockInputNode2.Verify(mock => mock.ClearCachedErrors(), Times.Exactly(NumEpochs * inputs.Length));
mockInputNode1.Verify(mock => mock.ApplyWeightAdjustments(LearningRate, Momentum), Times.Exactly(NumEpochs));
mockInputNode2.Verify(mock => mock.ApplyWeightAdjustments(LearningRate, Momentum), Times.Exactly(NumEpochs));
// Use of output nodes
mockOutputNode1.VerifyGet(mock => mock.CachedOutputs, Times.AtLeast(NumEpochs));
mockOutputNode2.VerifyGet(mock => mock.CachedOutputs, Times.AtLeast(NumEpochs));
mockOutputNode1.Verify(mock => mock.CalculateError(overallErrors[0][0]), Times.Exactly(NumEpochs));
mockOutputNode1.Verify(mock => mock.CalculateError(overallErrors[1][0]), Times.Exactly(NumEpochs));
mockOutputNode2.Verify(mock => mock.CalculateError(overallErrors[0][1]), Times.Exactly(NumEpochs));
mockOutputNode2.Verify(mock => mock.CalculateError(overallErrors[1][1]), Times.Exactly(NumEpochs));
// Verify Error
Assert.AreEqual(FinalError, actualError);
}