static NDMaskPtr CreateMask(size_t sampleSize, const std::vector<std::vector<T>>& sequences, const DeviceDescriptor& device)
{
size_t numSequences = sequences.size();
std::vector<size_t> sequenceLengths(numSequences);
size_t maxSequenceLength = 0;
bool needsMask = false;
for (size_t i = 0; i < numSequences; ++i)
{
sequenceLengths[i] = sequences[i].size() / sampleSize;
if (maxSequenceLength < sequenceLengths[i])
maxSequenceLength = sequenceLengths[i];
if ((i > 0) && (sequenceLengths[i - 1] != sequenceLengths[i]))
needsMask = true;
}
NDMaskPtr deviceValueMask;
if (needsMask)
{
NDShape valueMaskShape = { maxSequenceLength, numSequences };
deviceValueMask = NDMaskPtr(new NDMask(valueMaskShape, device), [](Internal::ReferenceCount* ptr) {delete ptr; });
for (size_t i = 0; i < numSequences; ++i)
deviceValueMask->MaskSection({ sequenceLengths[i], i }, { NDShape::InferredDimension, 1 });
}
return deviceValueMask;
}
static NDMaskPtr CreateMask(size_t numElementsPerSample, const std::vector<std::vector<T>>& sequences, const DeviceDescriptor& device)
{
size_t numSequences = sequences.size();
std::vector<size_t> sequenceLengths(numSequences);
size_t maxSequenceLength = 0;
bool needsMask = false;
for (size_t i = 0; i < numSequences; ++i)
{
sequenceLengths[i] = sequences[i].size() / numElementsPerSample;
if (maxSequenceLength < sequenceLengths[i])
maxSequenceLength = sequenceLengths[i];
if ((i > 0) && (sequenceLengths[i - 1] != sequenceLengths[i]))
needsMask = true;
}
// If needed, create a mask to account for variability in lengths of specified sequences
NDMaskPtr deviceValueMask;
if (needsMask)
{
NDShape valueMaskShape = { maxSequenceLength, numSequences };
deviceValueMask = MakeSharedObject<NDMask>(valueMaskShape, device);
for (size_t i = 0; i < numSequences; ++i)
{
deviceValueMask->MarkSequenceBegin({0, i});
deviceValueMask->InvalidateSection({ sequenceLengths[i], i }, { NDShape::InferredDimension, 1 });
}
}
return deviceValueMask;
}
