fastmks_stat.hpp

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#ifndef MLPACK_METHODS_FASTMKS_FASTMKS_STAT_HPP
#define MLPACK_METHODS_FASTMKS_FASTMKS_STAT_HPP

#include <mlpack/prereqs.hpp>
#include <mlpack/core/tree/tree_traits.hpp>

namespace mlpack {
namespace fastmks {

class FastMKSStat
{
 public:
  FastMKSStat() :
      bound(-DBL_MAX),
      selfKernel(0.0),
      lastKernel(0.0),
      lastKernelNode(NULL)
  { }

  template<typename TreeType>
  FastMKSStat(const TreeType& node) :
      bound(-DBL_MAX),
      lastKernel(0.0),
      lastKernelNode(NULL)
  {
    // Do we have to calculate the centroid?
    if (tree::TreeTraits<TreeType>::FirstPointIsCentroid)
    {
      // If this type of tree has self-children, then maybe the evaluation is
      // already done.  These statistics are built bottom-up, so the child stat
      // should already be done.
      if ((tree::TreeTraits<TreeType>::HasSelfChildren) &&
          (node.NumChildren() > 0) &&
          (node.Point(0) == node.Child(0).Point(0)))
      {
        selfKernel = node.Child(0).Stat().SelfKernel();
      }
      else
      {
        selfKernel = sqrt(node.Metric().Kernel().Evaluate(
            node.Dataset().col(node.Point(0)),
            node.Dataset().col(node.Point(0))));
      }
    }
    else
    {
      // Calculate the centroid.
      arma::vec center;
      node.Center(center);

      selfKernel = sqrt(node.Metric().Kernel().Evaluate(center, center));
    }
  }

  double SelfKernel() const { return selfKernel; }
  double& SelfKernel() { return selfKernel; }

  double Bound() const { return bound; }
  double& Bound() { return bound; }

  double LastKernel() const { return lastKernel; }
  double& LastKernel() { return lastKernel; }

  void* LastKernelNode() const { return lastKernelNode; }
  void*& LastKernelNode() { return lastKernelNode; }

  template<typename Archive>
  void serialize(Archive& ar, const uint32_t /* version */)
  {
    ar(CEREAL_NVP(bound));
    ar(CEREAL_NVP(selfKernel));

    // Void out last kernel information on load.
    if (cereal::is_loading<Archive>())
    {
      lastKernel = 0.0;
      lastKernelNode = NULL;
    }
  }

 private:
  double bound;

  double selfKernel;

  double lastKernel;

  void* lastKernelNode;
};

} // namespace fastmks
} // namespace mlpack

#endif