silu_function.hpp

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#ifndef MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_SILU_FUNCTION_HPP
#define MLPACK_METHODS_ANN_ACTIVATION_FUNCTIONS_SILU_FUNCTION_HPP

#include <mlpack/prereqs.hpp>

namespace mlpack {
namespace ann /* Artificial Neural Network */ {

class SILUFunction
{
 public:
  static double Fn(const double x)
  {
    return x / (1.0 + std::exp(-x));
  }

  template<typename InputVecType, typename OutputVecType>
  static void Fn(const InputVecType &x, OutputVecType &y)
  {
    y = x / (1.0 + arma::exp(-x));
  }

  static double Deriv(const double x)
  {
    double sigmoid = 1.0 / (1.0 + std::exp(-x));
    return sigmoid * (1.0 + x * (1.0 - sigmoid));
  }

  template<typename InputVecType, typename OutputVecType>
  static void Deriv(const InputVecType &x, OutputVecType &y)
  {
    OutputVecType sigmoid = 1.0 / (1.0 + arma::exp(-x));
    y = sigmoid % (1.0 + x % (1.0 - sigmoid));
  }
}; // class SILUFunction

} // namespace ann
} // namespace mlpack

#endif