Public Member Functions | Protected Member Functions | Protected Attributes

CEuclidianDistance Class Reference


Detailed Description

class EuclidianDistance

The familiar Euclidian distance for real valued features computes the square root of the sum of squared disparity between the corresponding feature dimensions of two data points.

\[\displaystyle d({\bf x},{\bf x'})= \sqrt{\sum_{i=0}^{n}|{\bf x_i}-{\bf x'_i}|^2} \]

This special case of Minkowski metric is invariant to an arbitrary translation or rotation in feature space.

The Euclidian Squared distance does not take the square root:

\[\displaystyle d({\bf x},{\bf x'})= \sum_{i=0}^{n}|{\bf x_i}-{\bf x'_i}|^2 \]

See also:
CMinkowskiMetric
Wikipedia: Distance in Euclidean space

Definition at line 43 of file EuclidianDistance.h.

Inheritance diagram for CEuclidianDistance:
Inheritance graph
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List of all members.

Public Member Functions

 CEuclidianDistance ()
 CEuclidianDistance (CSimpleFeatures< float64_t > *l, CSimpleFeatures< float64_t > *r)
virtual ~CEuclidianDistance ()
virtual bool init (CFeatures *l, CFeatures *r)
virtual void cleanup ()
virtual EDistanceType get_distance_type ()
virtual EFeatureType get_feature_type ()
virtual const char * get_name () const
virtual bool get_disable_sqrt ()
virtual void set_disable_sqrt (bool state)

Protected Member Functions

virtual float64_t compute (int32_t idx_a, int32_t idx_b)

Protected Attributes

bool disable_sqrt

Constructor & Destructor Documentation

default constructor

Definition at line 19 of file EuclidianDistance.cpp.

constructor

Parameters:
l features of left-hand side
r features of right-hand side

Definition at line 24 of file EuclidianDistance.cpp.

~CEuclidianDistance (  )  [virtual]

Definition at line 31 of file EuclidianDistance.cpp.


Member Function Documentation

void cleanup (  )  [virtual]

cleanup distance

Implements CRealDistance.

Definition at line 43 of file EuclidianDistance.cpp.

float64_t compute ( int32_t  idx_a,
int32_t  idx_b 
) [protected, virtual]

compute kernel function for features a and b idx_{a,b} denote the index of the feature vectors in the corresponding feature object

Implements CRealDistance.

Definition at line 47 of file EuclidianDistance.cpp.

virtual bool get_disable_sqrt (  )  [virtual]

disable application of sqrt on matrix computation the matrix can then also be named norm squared

Returns:
if application of sqrt is disabled

Definition at line 91 of file EuclidianDistance.h.

virtual EDistanceType get_distance_type (  )  [virtual]

get distance type we are

Returns:
distance type EUCLIDIAN

Implements CRealDistance.

Definition at line 72 of file EuclidianDistance.h.

virtual EFeatureType get_feature_type (  )  [virtual]

get feature type the distance can deal with

Returns:
feature type DREAL

Reimplemented from CRealDistance.

Definition at line 78 of file EuclidianDistance.h.

virtual const char* get_name ( void   )  const [virtual]

get name of the distance

Returns:
name Euclidian

Reimplemented from CRealDistance.

Definition at line 84 of file EuclidianDistance.h.

bool init ( CFeatures l,
CFeatures r 
) [virtual]

init distance

Parameters:
l features of left-hand side
r features of right-hand side
Returns:
if init was successful

Reimplemented from CRealDistance.

Definition at line 36 of file EuclidianDistance.cpp.

virtual void set_disable_sqrt ( bool  state  )  [virtual]

disable application of sqrt on matrix computation the matrix can then also be named norm squared

Parameters:
state new disable_sqrt

Definition at line 98 of file EuclidianDistance.h.


Member Data Documentation

bool disable_sqrt [protected]

if application of sqrt on matrix computation is disabled

Definition at line 111 of file EuclidianDistance.h.


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