projection_vector.hpp

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#ifndef MLPACK_CORE_TREE_SPILL_TREE_PROJECTION_VECTOR_HPP
#define MLPACK_CORE_TREE_SPILL_TREE_PROJECTION_VECTOR_HPP

#include <mlpack/prereqs.hpp>
#include "../bounds.hpp"
namespace mlpack {
namespace tree {

class AxisParallelProjVector
{
  size_t dim;

 public:
  AxisParallelProjVector(size_t dim = 0) :
      dim(dim)
  {};

  template<typename VecType>
  double Project(const VecType& point,
                 typename std::enable_if_t<IsVector<VecType>::value>* = 0) const
  {
    return point[dim];
  };

  template<typename MetricType, typename ElemType>
  math::RangeType<ElemType> Project(
      const bound::HRectBound<MetricType, ElemType>& bound) const
  {
    return bound[dim];
  };

  template<typename MetricType, typename VecType>
  math::RangeType<typename VecType::elem_type> Project(
      const bound::BallBound<MetricType, VecType>& bound) const
  {
    return bound[dim];
  };

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

class ProjVector
{
  arma::vec projVect;

 public:
  ProjVector() :
      projVect()
  {};

  ProjVector(const arma::vec& vect) :
      projVect(arma::normalise(vect))
  {};

  template<typename VecType>
  double Project(const VecType& point,
                 typename std::enable_if_t<IsVector<VecType>::value>* = 0) const
  {
    return arma::dot(point, projVect);
  };

  template<typename MetricType, typename VecType>
  math::RangeType<typename VecType::elem_type> Project(
      const bound::BallBound<MetricType, VecType>& bound) const
  {
    typedef typename VecType::elem_type ElemType;
    const double center = Project(bound.Center());
    const ElemType radius = bound.Radius();
    return math::RangeType<ElemType>(center - radius, center + radius);
  };

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

} // namespace tree
} // namespace mlpack

#endif