nca_softmax_error_function.hpp

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#ifndef MLPACK_METHODS_NCA_NCA_SOFTMAX_ERROR_FUNCTION_HPP
#define MLPACK_METHODS_NCA_NCA_SOFTMAX_ERROR_FUNCTION_HPP
 
#include <mlpack/prereqs.hpp>
#include <mlpack/core/metrics/lmetric.hpp>
#include <mlpack/core/math/make_alias.hpp>
#include <mlpack/core/math/shuffle_data.hpp>
 
namespace mlpack {
namespace nca {
 
template<typename MetricType = metric::SquaredEuclideanDistance>
class SoftmaxErrorFunction
{
 public:
  SoftmaxErrorFunction(const arma::mat& dataset,
                       const arma::Row<size_t>& labels,
                       MetricType metric = MetricType());
 
  void Shuffle();
 
  double Evaluate(const arma::mat& covariance);
 
  double Evaluate(const arma::mat& covariance,
                  const size_t begin,
                  const size_t batchSize = 1);
 
  void Gradient(const arma::mat& covariance, arma::mat& gradient);
 
  template <typename GradType>
  void Gradient(const arma::mat& covariance,
                const size_t begin,
                GradType& gradient,
                const size_t batchSize = 1);
 
  const arma::mat GetInitialPoint() const;
 
  size_t NumFunctions() const { return dataset.n_cols; }
 
 private:
  arma::mat dataset;
  arma::Row<size_t> labels;
 
  MetricType metric;
 
  arma::mat lastCoordinates;
  arma::mat stretchedDataset;
  arma::vec p;
  arma::vec denominators;
 
  bool precalculated;
 
  void Precalculate(const arma::mat& coordinates);
};
 
} // namespace nca
} // namespace mlpack
 
// Include implementation.
#include "nca_softmax_error_function_impl.hpp"
 
#endif