Defines a metric in the Euclidian space where only the square of the distances are being computed into a scalar value expressed with the DistanceType which is one of C++'s arithmetic types. More...

#include <metric.hpp>

Inherits Diff.

Inherited by spatial::details::Compress< quadrance< Ct, DistanceType, Diff >, typename spatial::container_traits< const Ct >::key_type > [private], and spatial::details::Compress< quadrance< Ct, DistanceType, Diff >, typename spatial::container_traits< Ct >::key_type > [private].

Public Types
typedef details::rebind_builtin_difference< Diff, DistanceType >::type	difference_type
	The type used to compute the difference between 2 keys along the same dimension. More...

typedef DistanceType	distance_type

Public Member Functions
	quadrance (const difference_type &diff=Diff())
	The constructor allows you to specify a custom difference type. More...

template<typename AnyDistanceType >
	quadrance (const quadrance< Ct, AnyDistanceType, Diff > &other)
	Copy the metric from another metric with any DistanceType. More...

distance_type	distance_to_key (dimension_type rank, const key_type &origin, const key_type &key) const
	Compute the distance between the point of `origin` and the `key`. More...

distance_type	distance_to_plane (dimension_type, dimension_type dim, const key_type &origin, const key_type &key) const
	The distance between the point of `origin` and the closest point to the plane orthogonal to the axis of dimension `dim` and crossing `key`. More...

difference_type	difference () const
	Returns the difference functor used in this type. More...

Private Types
typedef enable_if< import::is_arithmetic< DistanceType > >::type	check_concept_distance_type_is_arithmetic

typedef container_traits< Ct >::key_type	key_type
	The key_type of the container being used for calculations. More...

Detailed Description

template<typename Ct, typename DistanceType, typename Diff>
class spatial::quadrance< Ct, DistanceType, Diff >

Defines a metric in the Euclidian space where only the square of the distances are being computed into a scalar value expressed with the DistanceType which is one of C++'s arithmetic types.

Concept:: This object is a model of Metric

This method of distance calculation is more flexible than spatial::euclidian since it can support all of the C++'s arithmetic types.

When using this metric and reading the distance value, you must remember that you are reading the square of the distance, and not the real distance. Thus, you should use square root to recover the real distance.

This metric has one important drawback: if you are working with large value over the entire range permissible by DistanceType, then chances that the computation overflows is non-negligible. To receive an arithmetic_error exception upon overflow, compile your application with #define SPATIAL_SAFER_ARITHEMTICS.

Definition at line 138 of file metric.hpp.