poisson1_function.hpp

#ifndef MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_POISSON1_FUNCTION_HPP
#define MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_POISSON1_FUNCTION_HPP

#include <mlpack/prereqs.hpp>

namespace mlpack {
namespace ann  {

class Poisson1Function
{
 public:
  static double Fn(const double x)
  {
    return (x - 1) * std::exp(-x);
  }

  template<typename InputVecType, typename OutputVecType>
  static void Fn(const InputVecType& x, OutputVecType& y)
  {
    y = (x - 1) % arma::exp(-x);
  }

  static double Deriv(const double y)
  {
    return  std::exp(-y) + (1 - y) * std::exp(-y);
  }

  template<typename InputVecType, typename OutputVecType>
  static void Deriv(const InputVecType& x, OutputVecType& y)
  {
    y = arma::exp(-x) + (1 - x) % arma::exp(-x);
  }
}; // class Poisson1Function

} // namespace ann
} // namespace mlpack

#endif