src/neuralnet/neuron_layer/sigmoid.cc

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#include <glog/logging.h>
#include "singa/neuralnet/neuron_layer.h"
#include "singa/utils/singleton.h"


namespace singa {

using std::vector;

void SigmoidLayer::Setup(const LayerProto& conf,
    const vector<Layer*>& srclayers) {
  Layer::Setup(conf, srclayers);
  data_.ReshapeLike(srclayers[0]->data(this));
  grad_.ReshapeLike(srclayers[0]->grad(this));
}

void SigmoidLayer::ComputeFeature(int flag, const vector<Layer*>& srclayers) {
  auto data = Tensor1(&data_);
  auto src = Tensor1(srclayers[0]->mutable_data(this));
  data = expr::F<op::sigmoid>(src);
}

void SigmoidLayer::ComputeGradient(int flag, const vector<Layer*>& srclayers) {
  auto data = Tensor1(&data_);
  auto grad = Tensor1(&grad_);
  auto gsrc = Tensor1(srclayers[0]->mutable_grad(this));
  gsrc = expr::F<op::sigmoid_grad>(data) * grad;
}

}  //  namespace singa