cvr::quickMedian Class Reference
[Statistics]

Quick median search. More...

#include <cvrQuickMedian.h>

Inheritance diagram for cvr::quickMedian:

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Collaboration diagram for cvr::quickMedian:

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List of all members.

Classes
class	parameters
	The parameters for the class quickMedian. More...
Public Member Functions
	quickMedian ()
	quickMedian (const parameters &param)
	quickMedian (const eMedianEvenCase medianEvenCase)
	quickMedian (const quickMedian &other)
virtual	~quickMedian ()
const std::string &	name () const
template<typename T >
bool	apply (matrix< T > &src, T &median) const
template<typename T >
bool	apply (const matrix< T > &src, T &median) const
template<typename T >
bool	apply (const matrix< T > &src, matrix< T > &dest, T &median) const
template<class V >
bool	apply (V &srcdest, typename V::value_type &median) const
template<class V >
bool	apply (const V &src, typename V::value_type &median) const
template<class V >
bool	apply (const V &src, V &dest, typename V::value_type &median) const
template<class V >
V::value_type	median (const V &src) const
quickMedian &	copy (const quickMedian &other)
virtual quickMedian *	clone () const
virtual quickMedian *	newInstance () const
const parameters &	getParameters () const
Protected Member Functions
template<class V >
V::value_type	findMedian (V &vct, const int begin, const int end, const int medianPos) const
template<class V >
int	partition (V &vct, const int begin, const int end) const

---

Detailed Description

Quick median search.

This class is used to extract the median of the elements of a given vector or matrix. The median is defined as the element at the middle position of the sorted vector. The algorithm used is based on the quick sort. For vectors (or matrices) with an even number n of elements, the median will be the element at (n/2) or (n/2)-1 depending on the parameter settings.

On-place applies are in this implementation faster than on copy ones.

The type of the vector elements (T) must accept the operators < and >.

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Constructor & Destructor Documentation

cvr::quickMedian::quickMedian

(

)

Default constructor.

cvr::quickMedian::quickMedian

(

const parameters &

param

)

Constructor to set parameters.

cvr::quickMedian::quickMedian

(

const eMedianEvenCase

medianEvenCase

)

Constructor with indicator what to do for even-sized vectors.

cvr::quickMedian::quickMedian

(

const quickMedian &

other

)

copy constructor

Parameters:

other

the object to be copied

virtual cvr::quickMedian::~quickMedian

(

)

[virtual]

destructor

---

Member Function Documentation

template<class V >

bool cvr::quickMedian::apply	(	const V &	src,
		V &	dest,
		typename V::value_type &	median
	)			const [inline]

Operates on the given parameter.

Parameters:

	src	vector with the source data.
	dest	the partially sorted vector. The elements at the first half of the vector are less or equal than the median and on the other half greater or equal.
	median	the median value

Returns:

true on success false otherwise

template<class V >

bool cvr::quickMedian::apply	(	const V &	src,
		typename V::value_type &	median
	)			const [inline]

Operates on the given parameter.

Parameters:

	src	vector with the source data.
	median	the median value

Returns:

true on success false otherwise

template<class V >

bool cvr::quickMedian::apply	(	V &	srcdest,
		typename V::value_type &	median
	)			const [inline]

Find the median of a vector type V, which can be an cvr::genericVector or its derived classes, or a std::vector.

In principle the container type V just needs to support:

• the type definitions V::size_type and V::value_type,
• the operator[] returning elements of type V::value_type
• the V::value_type has to be comparable with the operator<.
• the method empty()
• the method size() returning a V::size_type

The resulting vector contains the elements less or equal than the median for the indexes x such that x < size()/2, and higher or equal otherwise.

Parameters:

	srcdest	vector<T> with the source data. The result will be left here too.
	median	the median value

Returns:

true on success false otherwise

template<typename T >

bool cvr::quickMedian::apply	(	const matrix< T > &	src,
		matrix< T > &	dest,
		T &	median
	)			const [inline]

Calculates the median of src, the result is left in dest.

The elements of the matrix will be considered as part of a vector with "columns()" times "rows()" elements.

Parameters:

	src	matrix<T> with the source data.
	dest	partially sorted matrix.
	median	the median value of the given matrix.

Returns:

true on success false otherwise

template<typename T >

bool cvr::quickMedian::apply	(	const matrix< T > &	src,
		T &	median
	)			const [inline]

Calculates the median of the given matrix, which is NOT modified.

The elements of the matrix will be considered as part of a vector with "columns()" times "rows()" elements.

Parameters:

	src	matrix<T> with the source data.
	median	the median value of the given matrix.

Returns:

true on success false otherwise

template<typename T >

bool cvr::quickMedian::apply	(	matrix< T > &	src,
		T &	median
	)			const [inline]

Calculates the median of the given matrix, which WILL BE modified.

The elements of the matrix will be considered as part of a vector with "columns()" times "rows()" elements.

Parameters:

	src	matrix<T> with the source data.
	median	the median value of the given matrix.

Returns:

true on success false otherwise

virtual quickMedian* cvr::quickMedian::clone

(

)

const [virtual]

Returns a pointer to a clone of this functor.

Implements cvr::functor.

quickMedian& cvr::quickMedian::copy

(

const quickMedian &

other

)

Copy data of "other" functor.

Parameters:

other

the functor to be copied

Returns:

a reference to this functor object

template<class V >

V::value_type cvr::quickMedian::findMedian	(	V &	vct,
		const int	begin,
		const int	end,
		const int	medianPos
	)			const [inline, protected]

This method calculates the median in a recursively form.

The template type V has to be a vector following an interface like the cvr::vector or the std::vector, implementing the operator[]

const parameters& cvr::quickMedian::getParameters

(

)

const

Returns used parameters.

Reimplemented from cvr::parametersManager.

template<class V >

V::value_type cvr::quickMedian::median

(

const V &

src

)

const [inline]

A shortcut function for apply(const vector<T>&, T&) const.

Note that internally another vector and T are used.

Parameters:

src

vector whose median is sought

Returns:

the median of src

const std::string& cvr::quickMedian::name

(

)

const [virtual]

Returns the name of this class.

Implements cvr::functor.

virtual quickMedian* cvr::quickMedian::newInstance

(

)

const [virtual]

Returns a pointer to a new instance of this functor.

Implements cvr::functor.

template<class V >

int cvr::quickMedian::partition	(	V &	vct,
		const int	begin,
		const int	end
	)			const [inline, protected]

This method chooses a pivot-value and ensures that lower values lie at the left and higher values at the right of its final position, which will be returned.

The template type V has to be a vector following an interface like the cvr::vector or the std::vector, implementing the operator[]

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

• cvrQuickMedian.h