public NDArray Predict(NDArray x, uint?batchSize = null)
{
NDArray result = new NDArray();
List <float> preds = new List <float>();
NDArrayIter dataIter = new NDArrayIter(new NDArray[] { x }, null);
if (!batchSize.HasValue)
{
batchSize = x.Shape[0];
}
List <uint> inputShape = new List <uint>();
NDArrayDict predictArgs = new NDArrayDict();
Model.InferArgsMap(mx.Device, predictArgs, args);
predictArgs["X"] = new NDArray(x.Shape);
predictArgs["label"] = new NDArray(new Shape(batchSize.Value));
using (var exec = Model.SimpleBind(mx.Device, predictArgs))
{
dataIter.BatchSize = batchSize.Value;
dataIter.Reset();
while (dataIter.IterNext())
{
var batch = dataIter.Next();
batch.Data[0].CopyTo(predictArgs["X"]);
exec.Forward(false);
preds.AddRange(exec.Output.GetValues <float>());
}
}
return(new NDArray(preds.ToArray()).Reshape((int)x.Shape[0], -1));
}
public static void Run()
{
// Create
var trainX = new NDArray(new float[] { 0, 0, 0, 1, 1, 0, 1, 1 }).Reshape(4, 2);
var trainY = new NDArray(new float[] { 0, 1, 1, 0 });
var batch_size = 2;
var train_data = new NDArrayIter(trainX, trainY, batch_size);
var val_data = new NDArrayIter(trainX, trainY, batch_size);
var net = new Sequential();
net.Add(new Dense(64, ActivationType.Relu));
net.Add(new Dense(1));
var gpus = TestUtils.ListGpus();
var ctxList = gpus.Count > 0 ? gpus.Select(x => Context.Gpu(x)).ToArray() : new[] { Context.Cpu() };
net.Initialize(new Uniform(), ctxList.ToArray());
var trainer = new Trainer(net.CollectParams(), new Adam());
var epoch = 1000;
var metric = new BinaryAccuracy();
var binary_crossentropy = new LogisticLoss();
float lossVal = 0;
for (var iter = 0; iter < epoch; iter++)
{
train_data.Reset();
lossVal = 0;
while (!train_data.End())
{
var batch = train_data.Next();
var data = Utils.SplitAndLoad(batch.Data[0], ctxList);
var label = Utils.SplitAndLoad(batch.Label[0], ctxList);
NDArrayList outputs = null;
using (var ag = Autograd.Record())
{
outputs = Enumerable.Zip(data, label, (x, y) =>
{
var z = net.Call(x);
NDArray loss = binary_crossentropy.Call(z, y);
loss.Backward();
lossVal += loss.Mean();
return(z);
}).ToList();
}
metric.Update(label, outputs.ToArray());
trainer.Step(batch.Data[0].Shape[0]);
}
var(name, acc) = metric.Get();
metric.Reset();
Console.WriteLine($"Loss: {lossVal}");
Console.WriteLine($"Training acc at epoch {iter}: {name}={acc * 100}%");
}
}
public static void RunSimple()
{
var mnist = TestUtils.GetMNIST(); //Get the MNIST dataset, it will download if not found
var batch_size = 100; //Set training batch size
var train_data = new NDArrayIter(mnist["train_data"], mnist["train_label"], batch_size);
var val_data = new NDArrayIter(mnist["test_data"], mnist["test_label"], batch_size);
// Define simple network with dense layers
var net = new Sequential();
net.Add(new Dense(128, ActivationType.Relu));
net.Add(new Dense(64, ActivationType.Relu));
net.Add(new Dense(10));
//Set context, multi-gpu supported
var gpus = TestUtils.ListGpus();
var ctx = gpus.Count > 0 ? gpus.Select(x => Context.Gpu(x)).ToArray() : new[] { Context.Cpu(0) };
//Initialize the weights
net.Initialize(new Xavier(magnitude: 2.24f), ctx);
//Create the trainer with all the network parameters and set the optimizer
var trainer = new Trainer(net.CollectParams(), new Adam());
var epoch = 10;
var metric = new Accuracy(); //Use Accuracy as the evaluation metric.
var softmax_cross_entropy_loss = new SoftmaxCrossEntropyLoss();
float lossVal = 0; //For loss calculation
for (var iter = 0; iter < epoch; iter++)
{
var tic = DateTime.Now;
// Reset the train data iterator.
train_data.Reset();
lossVal = 0;
// Loop over the train data iterator.
while (!train_data.End())
{
var batch = train_data.Next();
// Splits train data into multiple slices along batch_axis
// and copy each slice into a context.
var data = Utils.SplitAndLoad(batch.Data[0], ctx, batch_axis: 0);
// Splits train labels into multiple slices along batch_axis
// and copy each slice into a context.
var label = Utils.SplitAndLoad(batch.Label[0], ctx, batch_axis: 0);
var outputs = new NDArrayList();
// Inside training scope
NDArray loss = null;
for (int i = 0; i < data.Length; i++)
{
using (var ag = Autograd.Record())
{
var x = data[i];
var y = label[i];
var z = net.Call(x);
// Computes softmax cross entropy loss.
loss = softmax_cross_entropy_loss.Call(z, y);
outputs.Add(z);
}
// Backpropagate the error for one iteration.
loss.Backward();
lossVal += loss.Mean();
}
// Updates internal evaluation
metric.Update(label, outputs.ToArray());
// Make one step of parameter update. Trainer needs to know the
// batch size of data to normalize the gradient by 1/batch_size.
trainer.Step(batch.Data[0].Shape[0]);
}
var toc = DateTime.Now;
// Gets the evaluation result.
var(name, acc) = metric.Get();
// Reset evaluation result to initial state.
metric.Reset();
Console.Write($"Loss: {lossVal} ");
Console.WriteLine($"Training acc at epoch {iter}: {name}={(acc * 100).ToString("0.##")}%, Duration: {(toc - tic).TotalSeconds.ToString("0.#")}s");
}
}
public static void RunConv()
{
var mnist = TestUtils.GetMNIST();
var batch_size = 128;
var train_data = new NDArrayIter(mnist["train_data"], mnist["train_label"], batch_size, true);
var val_data = new NDArrayIter(mnist["test_data"], mnist["test_label"], batch_size);
var net = new Sequential();
net.Add(new Conv2D(20, kernel_size: (5, 5), activation: ActivationType.Tanh));
net.Add(new MaxPool2D(pool_size: (2, 2), strides: (2, 2)));
net.Add(new Conv2D(50, kernel_size: (5, 5), activation: ActivationType.Tanh));
net.Add(new MaxPool2D(pool_size: (2, 2), strides: (2, 2)));
net.Add(new Flatten());
net.Add(new Dense(500, ActivationType.Tanh));
net.Add(new Dense(10));
var gpus = TestUtils.ListGpus();
var ctx = gpus.Count > 0 ? gpus.Select(x => Context.Gpu(x)).ToArray() : new[] { Context.Cpu(0) };
net.Initialize(new Xavier(magnitude: 2.24f), ctx);
var trainer = new Trainer(net.CollectParams(), new SGD(learning_rate: 0.02f));
var epoch = 10;
var metric = new Accuracy();
var softmax_cross_entropy_loss = new SoftmaxCELoss();
float lossVal = 0;
for (var iter = 0; iter < epoch; iter++)
{
var tic = DateTime.Now;
train_data.Reset();
lossVal = 0;
while (!train_data.End())
{
var batch = train_data.Next();
var data = Utils.SplitAndLoad(batch.Data[0], ctx, batch_axis: 0);
var label = Utils.SplitAndLoad(batch.Label[0], ctx, batch_axis: 0);
var outputs = new NDArrayList();
using (var ag = Autograd.Record())
{
for (var i = 0; i < data.Length; i++)
{
var x = data[i];
var y = label[i];
var z = net.Call(x);
NDArray loss = softmax_cross_entropy_loss.Call(z, y);
loss.Backward();
lossVal += loss.Mean();
outputs.Add(z);
}
//outputs = Enumerable.Zip(data, label, (x, y) =>
//{
// var z = net.Call(x);
// NDArray loss = softmax_cross_entropy_loss.Call(z, y);
// loss.Backward();
// lossVal += loss.Mean();
// return z;
//}).ToList();
}
metric.Update(label, outputs.ToArray());
trainer.Step(batch.Data[0].Shape[0]);
}
var toc = DateTime.Now;
var(name, acc) = metric.Get();
metric.Reset();
Console.Write($"Loss: {lossVal} ");
Console.WriteLine($"Training acc at epoch {iter}: {name}={(acc * 100).ToString("0.##")}%, Duration: {(toc - tic).TotalSeconds.ToString("0.#")}s");
}
}