rectifier_function.hpp

Go to the documentation of this file.

#ifndef MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_RECTIFIER_FUNCTION_HPP
#define MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_RECTIFIER_FUNCTION_HPP

#include <mlpack/prereqs.hpp>
#include <algorithm>

namespace mlpack {
namespace ann  {

class RectifierFunction
{
 public:
  static double fn(const double x)
  {
    return std::max(0.0, x);
  }

  template<typename eT>
  static void fn(const arma::Mat<eT>& x, arma::Mat<eT>& y)
  {
    y = arma::max(arma::zeros<arma::Mat<eT> >(x.n_rows, x.n_cols), x);
  }

  template<typename eT>
  static void fn(const arma::Cube<eT>& x, arma::Cube<eT>& y)
  {
    y = x;
    for (size_t s = 0; s < x.n_slices; s++)
      fn(x.slice(s), y.slice(s));
  }

  static double deriv(const double y)
  {
    return y > 0;
  }

  template<typename InputType, typename OutputType>
  static void deriv(const InputType& y, OutputType& x)
  {
    x = y;

    for (size_t i = 0; i < y.n_elem; i++)
      x(i) = deriv(y(i));
  }
}; // class RectifierFunction

} // namespace ann
} // namespace mlpack

#endif