diagonal_gmm.hpp

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#ifndef MLPACK_METHODS_GMM_DIAGONAL_GMM_HPP
#define MLPACK_METHODS_GMM_DIAGONAL_GMM_HPP

#include <mlpack/prereqs.hpp>
#include <mlpack/core/dists/diagonal_gaussian_distribution.hpp>

// This is the default fitting method class.
#include "em_fit.hpp"

// This is the default covariance matrix constraint.
#include "diagonal_constraint.hpp"

namespace mlpack {
namespace gmm  {

class DiagonalGMM
{
 private:
  size_t gaussians;
  size_t dimensionality;

  std::vector<distribution::DiagonalGaussianDistribution> dists;

  arma::vec weights;

 public:
  DiagonalGMM() :
      gaussians(0),
      dimensionality(0)
  {
    // Warn the user.  They probably don't want to do this.  If this
    // constructor is being used (because it is required by some template
    // classes), the user should know that it is potentially dangerous.
    Log::Debug << "DiagonalGMM::DiagonalGMM(): no parameters given;"
        "Estimate() may fail " << "unless parameters are set." << std::endl;
  }

  DiagonalGMM(const size_t gaussians, const size_t dimensionality);

  DiagonalGMM(const std::vector<distribution::DiagonalGaussianDistribution>&
      dists, const arma::vec& weights) :
      gaussians(dists.size()),
      dimensionality((!dists.empty()) ? dists[0].Mean().n_elem : 0),
      dists(dists),
      weights(weights) { /* Nothing to do. */ }

  DiagonalGMM(const DiagonalGMM& other);

  DiagonalGMM& operator=(const DiagonalGMM& other);

  size_t Gaussians() const { return gaussians; }
  size_t Dimensionality() const { return dimensionality; }

  const distribution::DiagonalGaussianDistribution& Component(size_t i) const
  {
    return dists[i];
  }

  distribution::DiagonalGaussianDistribution& Component(size_t i)
  {
    return dists[i];
  }

  const arma::vec& Weights() const { return weights; }
  arma::vec& Weights() { return weights; }

  double Probability(const arma::vec& observation) const;

  double LogProbability(const arma::vec& observation) const;

  double Probability(const arma::vec& observation,
                     const size_t component) const;

  double LogProbability(const arma::vec& observation,
                        const size_t component) const;
  arma::vec Random() const;

  template<typename FittingType = EMFit<kmeans::KMeans<>, DiagonalConstraint,
      distribution::DiagonalGaussianDistribution>>
  double Train(const arma::mat& observations,
               const size_t trials = 1,
               const bool useExistingModel = false,
               FittingType fitter = FittingType());

  template<typename FittingType = EMFit<kmeans::KMeans<>, DiagonalConstraint,
      distribution::DiagonalGaussianDistribution>>
  double Train(const arma::mat& observations,
               const arma::vec& probabilities,
               const size_t trials = 1,
               const bool useExistingModel = false,
               FittingType fitter = FittingType());

  void Classify(const arma::mat& observations,
                arma::Row<size_t>& labels) const;

  template<typename Archive>
  void serialize(Archive& ar, const unsigned int /* version */);

 private:
  double LogLikelihood(
      const arma::mat& observations,
      const std::vector<distribution::DiagonalGaussianDistribution>& dists,
      const arma::vec& weights) const;
};

} // namespace gmm
} // namespace mlpack

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

#endif // MLPACK_METHODS_GMM_DIAGONAL_GMM_HPP