void ExpandLayer::backward(const UpdateCallback& callback) {
if (biases_ && biases_->getWGrad()) {
biases_->getWGrad()->collectBias(*getOutputGrad(), 1);
/* Increasing the number of gradient */
biases_->getParameterPtr()->incUpdate(callback);
}
if (!getInputGrad(0)) return;
MatrixPtr inputGrad = getInputGrad(0);
MatrixPtr outputGrad = getOutputGrad();
auto cpuSeqStartPos = type_ ? getInput(1).subSequenceStartPositions
: getInput(1).sequenceStartPositions;
size_t numSequences = cpuSeqStartPos->getSize() - 1;
const int* starts = cpuSeqStartPos->getData(false);
CHECK_EQ(inputGrad->getWidth(), outputGrad->getWidth());
CHECK_EQ(outputGrad->getHeight(), (size_t)starts[numSequences]);
AsyncGpuBlock asyncGpuBlock;
// sum to get the grad
real scale = 1;
for (size_t sequenceId = 0; sequenceId < numSequences; sequenceId++) {
// TODO(Dangqingqing) optimization for GPU
int sequenceLength = starts[sequenceId + 1] - starts[sequenceId];
if (sequenceLength == 0) {
// empty sequence
continue;
}
MatrixPtr copyData = inputGrad->subMatrix(sequenceId, 1);
copyData->collectBias(
*outputGrad->subMatrix(starts[sequenceId], sequenceLength), scale);
}
}
void DeConv3DLayer::bpropBiases() {
MatrixPtr biases = Matrix::create(biases_->getWGrad()->getData(),
1,
biases_->getWGrad()->getElementCnt(),
false,
useGpu_);
const MatrixPtr &outGradMat = getOutputGrad();
if (this->sharedBiases_) {
biases->collectSharedBias(*outGradMat, 1.0f);
} else {
biases->collectBias(*outGradMat, 1.0f);
}
}
void FeatureMapExpandLayer::backward(const UpdateCallback& callback) {
MatrixPtr inGrad = getInputGrad(0);
if (NULL == inGrad) {
return;
}
MatrixPtr outGrad = getOutputGrad();
size_t batchSize = getInput(0).getBatchSize();
int imgSize = inGrad->getWidth();
/* Do activation */ {
REGISTER_TIMER_INFO("BpAvtTimer", getName().c_str());
backwardActivation();
}
{
AsyncGpuBlock asyncGpuBlock;
if (asRowVector_) {
for (size_t i = 0; i < batchSize; i++) {
MatrixPtr outGradTmp =
Matrix::create(outGrad->getData() + i * imgSize * numFilters_,
numFilters_,
imgSize,
false,
useGpu_);
MatrixPtr inGradTmp = Matrix::create(
inGrad->getData() + i * imgSize, 1, imgSize, false, useGpu_);
inGradTmp->collectBias(*outGradTmp, 1);
}
} else {
for (size_t i = 0; i < batchSize; i++) {
MatrixPtr outGradTmp =
Matrix::create(outGrad->getData() + i * imgSize * numFilters_,
imgSize,
numFilters_,
false,
useGpu_);
MatrixPtr inGradTmp = Matrix::create(
inGrad->getData() + i * imgSize, imgSize, 1, false, useGpu_);
inGradTmp->sumRows(*outGradTmp, 1, 1);
}
}
}
}
