static double Evaluate(FunctionStack model, int[] dataset)
{
FunctionStack predictModel = (FunctionStack)model.Clone();
predictModel.ResetState();
Real totalLoss = 0;
long totalLossCount = 0;
for (int i = 0; i < dataset.Length - 1; i++)
{
NdArray x = new NdArray(new[] { 1 }, BATCH_SIZE);
NdArray t = new NdArray(new[] { 1 }, BATCH_SIZE);
for (int j = 0; j < BATCH_SIZE; j++)
{
x.Data[j] = dataset[j + i];
t.Data[j] = dataset[j + i + 1];
}
Real sumLoss = new SoftmaxCrossEntropy().Evaluate(predictModel.Forward(x), t);
totalLoss += sumLoss;
totalLossCount++;
}
//calc perplexity
return(Math.Exp(totalLoss / (totalLossCount - 1)));
}