connection_layer.h

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#ifndef SINGA_NEURALNET_CONNECTION_LAYER_H_
#define SINGA_NEURALNET_CONNECTION_LAYER_H_

#include <vector>
#include "neuralnet/layer.h"

namespace singa {
class BridgeLayer : virtual public ConnectionLayer {
 public:
  void set_ready(bool a) {
    ready_ = a;
  }
  bool ready() const {
    return ready_;
  }
  virtual bool is_bridgesrclayer() const {
    return false;
  }
  virtual bool is_bridgedstlayer() const {
    return false;
  }

 protected:
  bool ready_;
};

class BridgeDstLayer : public BridgeLayer {
 public:
  void Setup(const LayerProto& proto, int npartitions) override;
  void ComputeFeature(int flag, Metric* perf) override {
    // reset ready_ for next iteration.
    ready_ = false;
  }
  void ComputeGradient(int flag, Metric* perf) override {}
  bool is_bridgedstlayer() const {
    return true;
  }
};

class BridgeSrcLayer : public BridgeLayer {
 public:
  void ComputeFeature(int flag, Metric* perf) override {}
  void ComputeGradient(int flag, Metric* perf) override {
    ready_ = false;
  }
  const Blob<float>& data(const Layer* from) const override {
    return srclayers_[0]->data(this);
  }
  Blob<float>* mutable_data(const Layer* from) override {
    return srclayers_[0]->mutable_data(this);
  }
  const Blob<float>& grad(const Layer* from) const override {
    return srclayers_[0]->grad(this);
  }
  Blob<float>* mutable_grad(const Layer* from) override {
    return srclayers_[0]->mutable_grad(this);
  }
  bool is_bridgesrclayer() const override {
    return true;
  }
};


class ConcateLayer : public ConnectionLayer {
 public:
  void Setup(const LayerProto& proto, int npartitions) override;
  void ComputeFeature(int flag, Metric* perf) override;
  void ComputeGradient(int flag, Metric* perf) override;
};

class SliceLayer : public ConnectionLayer {
 public:
  void Setup(const LayerProto& proto, int npartitions) override;
  void ComputeFeature(int flag, Metric *perf) override;
  void ComputeGradient(int flag, Metric* perf) override;

 private:
  std::vector<Blob<float>> datavec_;
  std::vector<Blob<float>> gradvec_;
  int slice_dim_;
  int slice_num_;
};

class SplitLayer : public ConnectionLayer {
 public:
  void Setup(const LayerProto& proto, int npartitions) override;
  void ComputeFeature(int flag, Metric* perf) override;
  void ComputeGradient(int flag, Metric* perf) override;

 protected:
  Blob<float> grads_;
};

}  // namespace singa

#endif  // SINGA_NEURALNET_CONNECTION_LAYER_H_