metric.h

#ifndef SINGA_MODEL_METRIC_H_
#define SINGA_MODEL_METRIC_H_
#include "singa/core/tensor.h"
#include "singa/proto/model.pb.h"
namespace singa {

// template <typename T = Tensor>
class Metric {
 public:
  // TODO(wangwei) call Setup using a default MetricConf.
  Metric() = default;
  virtual ~Metric() {}
  virtual void ToDevice(std::shared_ptr<Device> device) {}
  void Setup(const string& conf) {
    MetricConf metric;
    metric.ParseFromString(conf);
    Setup(metric);
  }

  virtual void Setup(const MetricConf& conf) {}

  virtual Tensor Forward(const Tensor& prediction, const Tensor& target) = 0;

  float Evaluate(const Tensor& prediction, const Tensor& target) {
    const Tensor metric = Forward(prediction, target);
    return Sum<float>(metric) / (1.0f * metric.Size());
  }
};
class Accuracy : public Metric {
 public:
  void Setup(const MetricConf& conf) override { top_k_ = conf.top_k(); }

  Tensor Forward(const Tensor& prediction, const Tensor& target);

 private:
  Tensor Match(const Tensor& prediction, const vector<int>& target);
  size_t top_k_ = 1;
};


}  // namespace singa

#endif  // SINGA_MODEL_METRIC_H_