mlpack: mlpack::neighbor::NearestNeighborSort Class Reference
mlpack::neighbor::NearestNeighborSort Class Reference

This class implements the necessary methods for the SortPolicy template parameter of the NeighborSearch class. More...

Static Public Member Functions

static double BestDistance ()
 Return what should represent the best possible distance with this particular sort policy. More...
 
template<typename TreeType >
static double BestNodeToNodeDistance (const TreeType *queryNode, const TreeType *referenceNode)
 Return the best possible distance between two nodes. More...
 
template<typename TreeType >
static double BestNodeToNodeDistance (const TreeType *queryNode, const TreeType *referenceNode, const double centerToCenterDistance)
 Return the best possible distance between two nodes, given that the distance between the centers of the two nodes has already been calculated. More...
 
template<typename TreeType >
static double BestNodeToNodeDistance (const TreeType *queryNode, const TreeType *referenceNode, const TreeType *referenceChildNode, const double centerToCenterDistance)
 Return the best possible distance between the query node and the reference child node given the base case distance between the query node and the reference node. More...
 
template<typename VecType , typename TreeType >
static double BestPointToNodeDistance (const VecType &queryPoint, const TreeType *referenceNode)
 Return the best possible distance between a node and a point. More...
 
template<typename VecType , typename TreeType >
static double BestPointToNodeDistance (const VecType &queryPoint, const TreeType *referenceNode, const double pointToCenterDistance)
 Return the best possible distance between a point and a node, given that the distance between the point and the center of the node has already been calculated. More...
 
static double CombineBest (const double a, const double b)
 Return the best combination of the two distances. More...
 
static double CombineWorst (const double a, const double b)
 Return the worst combination of the two distances. More...
 
static bool IsBetter (const double value, const double ref)
 Return whether or not value is "better" than ref. More...
 
static size_t SortDistance (const arma::vec &list, const arma::Col< size_t > &indices, double newDistance)
 Return the index in the vector where the new distance should be inserted, or (size_t() - 1) if it should not be inserted (i.e. More...
 
static double WorstDistance ()
 Return what should represent the worst possible distance with this particular sort policy. More...
 

Detailed Description

This class implements the necessary methods for the SortPolicy template parameter of the NeighborSearch class.

The sorting policy here is that the minimum distance is the best (so, when used with NeighborSearch, the output is nearest neighbors).

This class is also meant to serve as a guide to implement a custom SortPolicy. All of the methods implemented here must be implemented by any other SortPolicy classes.

Definition at line 33 of file nearest_neighbor_sort.hpp.

Member Function Documentation

static double mlpack::neighbor::NearestNeighborSort::BestDistance ( )
inlinestatic

Return what should represent the best possible distance with this particular sort policy.

In our case, this should be the minimum possible distance, 0.0.

Returns
0.0

Definition at line 141 of file nearest_neighbor_sort.hpp.

template<typename TreeType >
static double mlpack::neighbor::NearestNeighborSort::BestNodeToNodeDistance ( const TreeType *  queryNode,
const TreeType *  referenceNode 
)
static

Return the best possible distance between two nodes.

In our case, this is the minimum distance between the two tree nodes using the given distance function.

Referenced by IsBetter().

template<typename TreeType >
static double mlpack::neighbor::NearestNeighborSort::BestNodeToNodeDistance ( const TreeType *  queryNode,
const TreeType *  referenceNode,
const double  centerToCenterDistance 
)
static

Return the best possible distance between two nodes, given that the distance between the centers of the two nodes has already been calculated.

This is used in conjunction with trees that have self-children (like cover trees).

template<typename TreeType >
static double mlpack::neighbor::NearestNeighborSort::BestNodeToNodeDistance ( const TreeType *  queryNode,
const TreeType *  referenceNode,
const TreeType *  referenceChildNode,
const double  centerToCenterDistance 
)
static

Return the best possible distance between the query node and the reference child node given the base case distance between the query node and the reference node.

TreeType::ParentDistance() must be implemented to use this.

Parameters
queryNodeQuery node.
referenceNodeReference node.
referenceChildNodeChild of reference node which is being inspected.
centerToCenterDistanceDistance between centers of query node and reference node.
template<typename VecType , typename TreeType >
static double mlpack::neighbor::NearestNeighborSort::BestPointToNodeDistance ( const VecType &  queryPoint,
const TreeType *  referenceNode 
)
static

Return the best possible distance between a node and a point.

In our case, this is the minimum distance between the tree node and the point using the given distance function.

Referenced by IsBetter().

template<typename VecType , typename TreeType >
static double mlpack::neighbor::NearestNeighborSort::BestPointToNodeDistance ( const VecType &  queryPoint,
const TreeType *  referenceNode,
const double  pointToCenterDistance 
)
static

Return the best possible distance between a point and a node, given that the distance between the point and the center of the node has already been calculated.

This is used in conjunction with trees that have self-children (like cover trees).

static double mlpack::neighbor::NearestNeighborSort::CombineBest ( const double  a,
const double  b 
)
inlinestatic

Return the best combination of the two distances.

Definition at line 146 of file nearest_neighbor_sort.hpp.

static double mlpack::neighbor::NearestNeighborSort::CombineWorst ( const double  a,
const double  b 
)
inlinestatic

Return the worst combination of the two distances.

Definition at line 154 of file nearest_neighbor_sort.hpp.

static bool mlpack::neighbor::NearestNeighborSort::IsBetter ( const double  value,
const double  ref 
)
inlinestatic

Return whether or not value is "better" than ref.

In this case, that means that the value is less than or equal to the reference.

Parameters
valueValue to compare
refValue to compare with
Returns
bool indicating whether or not (value <= ref).

Definition at line 63 of file nearest_neighbor_sort.hpp.

References BestNodeToNodeDistance(), and BestPointToNodeDistance().

static size_t mlpack::neighbor::NearestNeighborSort::SortDistance ( const arma::vec &  list,
const arma::Col< size_t > &  indices,
double  newDistance 
)
static

Return the index in the vector where the new distance should be inserted, or (size_t() - 1) if it should not be inserted (i.e.

if it is not any better than any of the existing points in the list). The list should be sorted such that the best point is the first in the list. The actual insertion is not performed.

Parameters
listVector of existing distance points, sorted such that the best point is first in the list.
new_distanceDistance to try to insert
Returns
size_t containing the position to insert into, or (size_t() - 1) if the new distance should not be inserted.
static double mlpack::neighbor::NearestNeighborSort::WorstDistance ( )
inlinestatic

Return what should represent the worst possible distance with this particular sort policy.

In our case, this should be the maximum possible distance, DBL_MAX.

Returns
DBL_MAX

Definition at line 132 of file nearest_neighbor_sort.hpp.


The documentation for this class was generated from the following file: