sgd.hpp

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#ifndef MLPACK_CORE_OPTIMIZERS_SGD_SGD_HPP
#define MLPACK_CORE_OPTIMIZERS_SGD_SGD_HPP

#include <mlpack/prereqs.hpp>
#include "update_policies/vanilla_update.hpp"
#include "update_policies/momentum_update.hpp"
#include "update_policies/nesterov_momentum_update.hpp"
#include "decay_policies/no_decay.hpp"

namespace mlpack {
namespace optimization {

template<typename UpdatePolicyType = VanillaUpdate,
         typename DecayPolicyType = NoDecay>
class SGD
{
 public:
  SGD(const double stepSize = 0.01,
      const size_t batchSize = 32,
      const size_t maxIterations = 100000,
      const double tolerance = 1e-5,
      const bool shuffle = true,
      const UpdatePolicyType& updatePolicy = UpdatePolicyType(),
      const DecayPolicyType& decayPolicy = DecayPolicyType(),
      const bool resetPolicy = true);

  template<typename DecomposableFunctionType>
  double Optimize(DecomposableFunctionType& function,
                  arma::mat& iterate);

  double StepSize() const { return stepSize; }
  double& StepSize() { return stepSize; }

  size_t BatchSize() const { return batchSize; }
  size_t& BatchSize() { return batchSize; }

  size_t MaxIterations() const { return maxIterations; }
  size_t& MaxIterations() { return maxIterations; }

  double Tolerance() const { return tolerance; }
  double& Tolerance() { return tolerance; }

  bool Shuffle() const { return shuffle; }
  bool& Shuffle() { return shuffle; }

  bool ResetPolicy() const { return resetPolicy; }
  bool& ResetPolicy() { return resetPolicy; }

  const UpdatePolicyType& UpdatePolicy() const { return updatePolicy; }
  UpdatePolicyType& UpdatePolicy() { return updatePolicy; }

  const DecayPolicyType& DecayPolicy() const { return decayPolicy; }
  DecayPolicyType& DecayPolicy() { return decayPolicy; }

 private:
  double stepSize;

  size_t batchSize;

  size_t maxIterations;

  double tolerance;

  bool shuffle;

  UpdatePolicyType updatePolicy;

  DecayPolicyType decayPolicy;

  bool resetPolicy;
};

using StandardSGD = SGD<VanillaUpdate>;

using MomentumSGD = SGD<MomentumUpdate>;

using NesterovMomentumSGD = SGD<NesterovMomentumUpdate>;

} // namespace optimization
} // namespace mlpack

// Include implementation.
#include "sgd_impl.hpp"

#endif