lstm_layer.hpp

#ifndef CAFFE_LSTM_LAYER_HPP_
#define CAFFE_LSTM_LAYER_HPP_

#include <string>
#include <utility>
#include <vector>

#include "caffe/blob.hpp"
#include "caffe/common.hpp"
#include "caffe/layer.hpp"
#include "caffe/layers/recurrent_layer.hpp"
#include "caffe/net.hpp"
#include "caffe/proto/caffe.pb.h"

namespace caffe {

template <typename Dtype> class RecurrentLayer;

template <typename Dtype>
class LSTMLayer : public RecurrentLayer<Dtype> {
 public:
  explicit LSTMLayer(const LayerParameter& param)
      : RecurrentLayer<Dtype>(param) {}

  virtual inline const char* type() const { return "LSTM"; }

 protected:
  virtual void FillUnrolledNet(NetParameter* net_param) const;
  virtual void RecurrentInputBlobNames(vector<string>* names) const;
  virtual void RecurrentOutputBlobNames(vector<string>* names) const;
  virtual void RecurrentInputShapes(vector<BlobShape>* shapes) const;
  virtual void OutputBlobNames(vector<string>* names) const;
};

template <typename Dtype>
class LSTMUnitLayer : public Layer<Dtype> {
 public:
  explicit LSTMUnitLayer(const LayerParameter& param)
      : Layer<Dtype>(param) {}
  virtual void Reshape(const vector<Blob<Dtype>*>& bottom,
      const vector<Blob<Dtype>*>& top);

  virtual inline const char* type() const { return "LSTMUnit"; }
  virtual inline int ExactNumBottomBlobs() const { return 3; }
  virtual inline int ExactNumTopBlobs() const { return 2; }

  virtual inline bool AllowForceBackward(const int bottom_index) const {
    // Can't propagate to sequence continuation indicators.
    return bottom_index != 2;
  }

 protected:
  virtual void Forward_cpu(const vector<Blob<Dtype>*>& bottom,
      const vector<Blob<Dtype>*>& top);
  virtual void Forward_gpu(const vector<Blob<Dtype>*>& bottom,
      const vector<Blob<Dtype>*>& top);

  virtual void Backward_cpu(const vector<Blob<Dtype>*>& top,
      const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom);
  virtual void Backward_gpu(const vector<Blob<Dtype>*>& top,
      const vector<bool>& propagate_down, const vector<Blob<Dtype>*>& bottom);

  int hidden_dim_;
  Blob<Dtype> X_acts_;
};

}  // namespace caffe

#endif  // CAFFE_LSTM_LAYER_HPP_