private static Function CreateMLPClassifier(DeviceDescriptor device, int numOutputClasses, int hiddenLayerDim, Function input, string classifierName)
{
Function dense1 = CNTKHelper.Dense(input, hiddenLayerDim, device, Activation.Sigmoid, "");
Function classifierOutput = CNTKHelper.Dense(dense1, numOutputClasses, device, Activation.None, classifierName);
return(classifierOutput);
}
public Model()
{
#region Create Models
mlpModel = CNTKHelper.CreateMLPModel(device, TEST1_SIZE, 1, TEST1_SIZE);
cnnModel = CNTKHelper.CreateCNNModel(device, TEST1_SIZE, 1, TEST1_SIZE);
#endregion
}
private static float[] ExpectedOutput(int size)
{
var result = new float[size * size];
for (int i = 0; i < size; i++)
{
var oneHot = CNTKHelper.OneHot(i, size);
for (int j = 0; j < size; j++)
{
result[i * size + j] = oneHot[j];
}
}
return(result);
}
private static float[] OneHotImages(int size)
{
var result = new float[size * size * size];
for (int k = 0; k < size; k++)
{
var oneHot = CNTKHelper.OneHot(k, size);
for (int i = 0; i < size; i++)
{
for (int j = 0; j < size; j++)
{
result[k * size * size + i * size + j] = oneHot[i];
}
}
}
return(result);
}
/// <summary>
/// Create convolution neural network
/// </summary>
/// <param name="features">input feature variable</param>
/// <param name="outDims">number of output classes</param>
/// <param name="device">CPU or GPU device to run the model</param>
/// <param name="classifierName">name of the classifier</param>
/// <returns>the convolution neural network classifier</returns>
static Function CreateConvolutionalNeuralNetwork(Variable features, int inputLayers, int outDims, DeviceDescriptor device, string classifierName)
{
// 28x28x1 -> 14x14x4
int kernelWidth1 = 3, kernelHeight1 = 3, outFeatureMapCount1 = 4;
int hStride1 = 2, vStride1 = 2;
int poolingWindowWidth1 = 3, poolingWindowHeight1 = 3;
Function pooling1 = ConvolutionWithMaxPooling(features, device, kernelWidth1, kernelHeight1,
inputLayers, outFeatureMapCount1, hStride1, vStride1, poolingWindowWidth1, poolingWindowHeight1);
// 14x14x4 -> 7x7x8
int kernelWidth2 = 3, kernelHeight2 = 3, numInputChannels2 = outFeatureMapCount1, outFeatureMapCount2 = 8;
int hStride2 = 2, vStride2 = 2;
int poolingWindowWidth2 = 3, poolingWindowHeight2 = 3;
Function pooling2 = ConvolutionWithMaxPooling(pooling1, device, kernelWidth2, kernelHeight2,
numInputChannels2, outFeatureMapCount2, hStride2, vStride2, poolingWindowWidth2, poolingWindowHeight2);
Function denseLayer = CNTKHelper.Dense(pooling2, outDims, device, Activation.None, classifierName);
return(denseLayer);
}
/// <summary>
/// Test a simple model which takes a one hot encoded digit as an input and returns the same as an output
/// </summary>
private void TrainAndEvaluateTest(Function model, Value inputValue)
{
#region Evaluate model before training
var inputDataMap = new Dictionary <Variable, Value>()
{
{ model.Arguments[0], inputValue }
};
var outputDataMap = new Dictionary <Variable, Value>()
{
{ model.Output, null }
};
model.Evaluate(inputDataMap, outputDataMap, DeviceDescriptor.CPUDevice);
IList <IList <float> > preTrainingOutput = outputDataMap[model.Output].GetDenseData <float>(model.Output);
for (int i = 0; i < TEST1_SIZE; i++)
{
Trace.WriteLine($"Argmax({i}): {CNTKHelper.ArgMax(preTrainingOutput[i].ToArray())}");
}
#endregion
#region Train Model
var labels = CNTKLib.InputVariable(new int[] { TEST1_SIZE }, DataType.Float, "Error Input");
var trainingLoss = CNTKLib.CrossEntropyWithSoftmax(new Variable(model), labels, "lossFunction");
var prediction = CNTKLib.ClassificationError(new Variable(model), labels, "classificationError");
// Set per sample learning rate
CNTK.TrainingParameterScheduleDouble learningRatePerSample = new CNTK.TrainingParameterScheduleDouble(0.003125, 1);
IList <Learner> parameterLearners = new List <Learner>()
{
Learner.SGDLearner(model.Parameters(), learningRatePerSample)
};
var trainer = Trainer.CreateTrainer(model, trainingLoss, prediction, parameterLearners);
// Create expected output
var expectedOutputValue = Value.CreateBatch <float>(new int[] { TEST1_SIZE }, ExpectedOutput(TEST1_SIZE), DeviceDescriptor.CPUDevice);
var inputMiniBatch = new MinibatchData(inputValue, TEST1_SIZE);
var outputMiniBatch = new MinibatchData(expectedOutputValue, TEST1_SIZE);
var arguments = new Dictionary <Variable, MinibatchData>
{
{ model.Arguments[0], inputMiniBatch },
{ labels, outputMiniBatch }
};
int epochs = 5;
while (epochs > 0)
{
trainer.TrainMinibatch(arguments, device);
epochs--;
}
#endregion
#region Evaluate Model after training
outputDataMap = new Dictionary <Variable, Value>()
{
{ model.Output, null }
};
model.Evaluate(inputDataMap, outputDataMap, DeviceDescriptor.CPUDevice);
IList <IList <float> > postTrainingOutput = outputDataMap[model.Output].GetDenseData <float>(model.Output);
int nbFail = 0;
for (int i = 0; i < TEST1_SIZE; i++)
{
int prepTrainValue = CNTKHelper.ArgMax(preTrainingOutput[i].ToArray());
int postTrainValue = CNTKHelper.ArgMax(postTrainingOutput[i].ToArray());
if (i != postTrainValue)
{
nbFail++;
}
Trace.WriteLine($"Argmax({i}): {prepTrainValue} ==> {postTrainValue}");
}
Trace.WriteLine($"Failure rate = ({nbFail}/{TEST1_SIZE})");
#endregion
}