protected internal override void Calculate(double[] theta)
{
model.VectorToParams(theta);
SentimentCostAndGradient.ModelDerivatives derivatives;
if (model.op.trainOptions.nThreads == 1)
{
derivatives = ScoreDerivatives(trainingBatch);
}
else
{
// TODO: because some addition operations happen in different
// orders now, this results in slightly different values, which
// over time add up to significantly different models even when
// given the same random seed. Probably not a big deal.
// To be more specific, for trees T1, T2, T3, ... Tn,
// when using one thread, we sum the derivatives T1 + T2 ...
// When using multiple threads, we first sum T1 + ... + Tk,
// then sum Tk+1 + ... + T2k, etc, for split size k.
// The splits are then summed in order.
// This different sum order results in slightly different numbers.
MulticoreWrapper <IList <Tree>, SentimentCostAndGradient.ModelDerivatives> wrapper = new MulticoreWrapper <IList <Tree>, SentimentCostAndGradient.ModelDerivatives>(model.op.trainOptions.nThreads, new SentimentCostAndGradient.ScoringProcessor(this
));
// use wrapper.nThreads in case the number of threads was automatically changed
foreach (IList <Tree> chunk in CollectionUtils.PartitionIntoFolds(trainingBatch, wrapper.NThreads()))
{
wrapper.Put(chunk);
}
wrapper.Join();
derivatives = new SentimentCostAndGradient.ModelDerivatives(model);
while (wrapper.Peek())
{
SentimentCostAndGradient.ModelDerivatives batchDerivatives = wrapper.Poll();
derivatives.Add(batchDerivatives);
}
}
// scale the error by the number of sentences so that the
// regularization isn't drowned out for large training batchs
double scale = (1.0 / trainingBatch.Count);
value = derivatives.error * scale;
value += ScaleAndRegularize(derivatives.binaryTD, model.binaryTransform, scale, model.op.trainOptions.regTransformMatrix, false);
value += ScaleAndRegularize(derivatives.binaryCD, model.binaryClassification, scale, model.op.trainOptions.regClassification, true);
value += ScaleAndRegularizeTensor(derivatives.binaryTensorTD, model.binaryTensors, scale, model.op.trainOptions.regTransformTensor);
value += ScaleAndRegularize(derivatives.unaryCD, model.unaryClassification, scale, model.op.trainOptions.regClassification, false, true);
value += ScaleAndRegularize(derivatives.wordVectorD, model.wordVectors, scale, model.op.trainOptions.regWordVector, true, false);
derivative = NeuralUtils.ParamsToVector(theta.Length, derivatives.binaryTD.ValueIterator(), derivatives.binaryCD.ValueIterator(), SimpleTensor.IteratorSimpleMatrix(derivatives.binaryTensorTD.ValueIterator()), derivatives.unaryCD.Values.GetEnumerator
(), derivatives.wordVectorD.Values.GetEnumerator());
}
