mean_shift.hpp

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#ifndef MLPACK_METHODS_MEAN_SHIFT_MEAN_SHIFT_HPP
#define MLPACK_METHODS_MEAN_SHIFT_MEAN_SHIFT_HPP

#include <mlpack/prereqs.hpp>
#include <mlpack/core/kernels/gaussian_kernel.hpp>
#include <mlpack/core/kernels/kernel_traits.hpp>
#include <mlpack/core/metrics/lmetric.hpp>
#include <boost/utility.hpp>

namespace mlpack {
namespace meanshift  {

template<bool UseKernel = false,
         typename KernelType = kernel::GaussianKernel,
         typename MatType = arma::mat>
class MeanShift
{
 public:
  MeanShift(const double radius = 0,
            const size_t maxIterations = 1000,
            const KernelType kernel = KernelType());

  double EstimateRadius(const MatType& data, const double ratio = 0.2);

  void Cluster(const MatType& data,
               arma::Col<size_t>& assignments,
               arma::mat& centroids,
               bool useSeeds = true);

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

  double Radius() const { return radius; }
  void Radius(double radius);

  const KernelType& Kernel() const { return kernel; }
  KernelType& Kernel() { return kernel; }

 private:
  void GenSeeds(const MatType& data,
                const double binSize,
                const int minFreq,
                MatType& seeds);

  template<bool ApplyKernel = UseKernel>
  typename std::enable_if<ApplyKernel, bool>::type
  CalculateCentroid(const MatType& data,
                    const std::vector<size_t>& neighbors,
                    const std::vector<double>& distances,
                    arma::colvec& centroid);

  template<bool ApplyKernel = UseKernel>
  typename std::enable_if<!ApplyKernel, bool>::type
  CalculateCentroid(const MatType& data,
                    const std::vector<size_t>& neighbors,
                    const std::vector<double>&, /*unused*/
                    arma::colvec& centroid);

  double radius;

  size_t maxIterations;

  KernelType kernel;
};

} // namespace meanshift
} // namespace mlpack

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

#endif // MLPACK_METHODS_MEAN_SHIFT_MEAN_SHIFT_HPP