casacore::HistAcc< T > Class Template Reference

Makes a histogram from input values. More...

#include <HistAcc.h>

Public Member Functions
	HistAcc (const uInt nBuff)
	Constructors and destructor. More...
	HistAcc (const uInt nBuff, const T width)
	HistAcc (const T low, const T high, const T width)
	HistAcc (const HistAcc &)
	~HistAcc ()
void	copy (const HistAcc &)
	Copy operations. More...
HistAcc &	operator= (const HistAcc &)
void	put (const T v)
	Accumulate (put) value(s) into the histogram. More...
void	put (const Array< T > &vv)
void	put (const Block< T > &vv)
void	reset ()
	Reset the contents of the bins to zero, but retain the current bin definition. More...
void	emptyBinsWithLessThan (const uInt nmin)
	Empty all bins whose contents is < nmin (e.g. More...
Fallible< T >	getPercentile (const Float p)
	The median is the 50-percentile (getPercentile(50)), i.e. More...
Fallible< T >	getMedian ()
Fallible< T >	getBinWidth () const
	All bins have the same width. More...
const StatAcc< T > &	getStatistics ()
	Get the internal Statistics accumulator (see StatAcc,h). More...
Fallible< uInt >	getHistogram (Block< uInt > &bins, Block< T > &values)
	The return value is the nr of histogram bins, and is invalid if the number is zero. More...
uInt	getSpurious (uInt &tooSmall, uInt &tooLarge)
	Get the nr of ‘spurious’ values, i.e. More...
void	printHistogram (ostream &, const String &caption)
	Print histogram. More...

Private Member Functions
void	put1 (const T)
	Accumulate a single value into the histogram. More...
void	defineBins (const T low, const T high, const T width)
	Definition of histogram bins with given parameters. More...
void	initBuffer (const uInt size)
	Internal helper functions for the automatic definition of histogram parameters, using the contents of itsBuffer. More...
void	putBuffer (const T v)
void	clearBuffer ()
void	autoDefineBins ()
void	init ()
	Other internal helper function(s). More...
Fallible< T >	getBinValue (const uInt index) const

Private Attributes
Block< uInt >	itsBinContents
Block< T >	itsBinHighLimit
T	itsUserDefinedBinWidth
StatAcc< T >	itsStatAcc
Bool	itsAutoDefineMode
Block< T >	itsBuffer
uInt	itsBufferContents

Detailed Description

template<class T>
class casacore::HistAcc< T >

Makes a histogram from input values.

Review Status

Test programs:

tHistAcc

Prerequisite

• module Arrays
• Arrays module

Etymology

HistAcc stands for ‘Histogram Accumulator’.

Template Type Argument Requirements (T)

• The accepted input types are real, i.e. Int, uInt, Float, Double, but not Complex.

Synopsis

Makes a histogram from input values. The histogram bin parameters may be defined, or determined from the first n input values. The input values are fed to HistAcc via the member function ‘put’. They can be fed individually, or in the form of an Array.

The histogram ‘bins’ can be defined via the constructor in the form of loop variables: low bin, high bin, bin-width. It is also possible to let the bin parameters be determined automatically from the first n (e.g. n=50) input values. If the actual nr of input values is less than n when the histogram is interrogated in some way, the bin parameters will be determined from what is available.

Example

It is usually convenient to let the bins be defined automatically:

Matrix<T> vv(30,100);        // an array of input values
vv =...                     // fill the array
HistAcc<T> h(25);            // use the first 25 values to define bins 
h.put(vv);                   // accumulate values into histogram 
h.printHistogram(cout,"vv"); // print the histogram of vv
Fallible<Double> median = h1.getMedian();  // return the median

In some cases the bin parameters are pre-defined:

Vector<T> vv(100,0);        // a vector (array) of values
vv =...                    // fill the vector
HistAcc<T> h(-10,20,3);     // bins with width 3, between -10 and 20
h.put(vv);                  // accumulate values into histogram   
uInt n = h.getSpurious(l,h);// get the number outside the bins

The internal statistics accumulator can be interrogated explicitly or implicitly:

StatAcc<T> s = h.getStatistics();     // return the internal StatAcc
Fallible<Double> mean = s.getMean();  // get the mean of the input values
Fallible<Double> mean = h.getStatistics().getMean();  // alternative

Motivation

Definition at line 118 of file HistAcc.h.

Constructor & Destructor Documentation

HistAcc() [1/4]

template<class T >

casacore::HistAcc< T >::HistAcc

(

const uInt

nBuff

)

Constructors and destructor.

If the bin-parameters low, high and width (for lowest and highest bin, and binwidth) are not specified, they will be determined automatically from the first nBuff input values (which are stored in a temporary buffer).

HistAcc() [2/4]

template<class T >

casacore::HistAcc< T >::HistAcc	(	const uInt	nBuff,
		const T	width
	)

HistAcc() [3/4]

template<class T >

casacore::HistAcc< T >::HistAcc	(	const T	low,
		const T	high,
		const T	width
	)

HistAcc() [4/4]

template<class T >

casacore::HistAcc< T >::HistAcc

(

const HistAcc< T > &

)

~HistAcc()

template<class T >

casacore::HistAcc< T >::~HistAcc ( )

inline

Definition at line 129 of file HistAcc.h.

Member Function Documentation

autoDefineBins()

template<class T >

void casacore::HistAcc< T >::autoDefineBins ( )

private

clearBuffer()

template<class T >

void casacore::HistAcc< T >::clearBuffer ( )

private

copy()

template<class T >

void casacore::HistAcc< T >::copy

(

const HistAcc< T > &

)

Copy operations.

defineBins()

template<class T >

void casacore::HistAcc< T >::defineBins ( const T  low, const T  high, const T  width  )

private

Definition of histogram bins with given parameters.

emptyBinsWithLessThan()

template<class T >

void casacore::HistAcc< T >::emptyBinsWithLessThan

(

const uInt

nmin

)

Empty all bins whose contents is < nmin (e.g.

nmin=2). This is useful to remove ‘noise’ values from the histogram.

getBinValue()

template<class T >

Fallible<T> casacore::HistAcc< T >::getBinValue ( const uInt  index ) const

private

getBinWidth()

template<class T >

Fallible<T> casacore::HistAcc< T >::getBinWidth

(

)

const

All bins have the same width.

getHistogram()

template<class T >

Fallible<uInt> casacore::HistAcc< T >::getHistogram	(	Block< uInt > &	bins,
		Block< T > &	values
	)

The return value is the nr of histogram bins, and is invalid if the number is zero.

The given blocks/vectors are resized, and contain the contents and centre values of the bins.

getMedian()

template<class T >

Fallible<T> casacore::HistAcc< T >::getMedian

(

)

getPercentile()

template<class T >

Fallible<T> casacore::HistAcc< T >::getPercentile

(

const Float

p

)

The median is the 50-percentile (getPercentile(50)), i.e.

the value which has 50 percent of the input values below it. Calculation takes into account the spurious input values, i.e. values that fell outside the bins.

getSpurious()

template<class T >

uInt casacore::HistAcc< T >::getSpurious	(	uInt &	tooSmall,
		uInt &	tooLarge
	)

Get the nr of ‘spurious’ values, i.e.

the ones that fell outside the defined bins.

getStatistics()

template<class T >

const StatAcc<T>& casacore::HistAcc< T >::getStatistics

(

)

Get the internal Statistics accumulator (see StatAcc,h).

It can be used to obtain statistics of the input values.

init()

template<class T >

void casacore::HistAcc< T >::init ( )

private

Other internal helper function(s).

initBuffer()

template<class T >

void casacore::HistAcc< T >::initBuffer ( const uInt  size )

private

Internal helper functions for the automatic definition of histogram parameters, using the contents of itsBuffer.

operator=()

template<class T >

HistAcc& casacore::HistAcc< T >::operator=

(

const HistAcc< T > &

)

printHistogram()

template<class T >

void casacore::HistAcc< T >::printHistogram	(	ostream &	,
		const String &	caption
	)

Print histogram.

put() [1/3]

template<class T >

void casacore::HistAcc< T >::put

(

const Array< T > &

vv

)

put() [2/3]

template<class T >

void casacore::HistAcc< T >::put

(

const Block< T > &

vv

)

put() [3/3]

template<class T >

void casacore::HistAcc< T >::put ( const T  v )

inline

Accumulate (put) value(s) into the histogram.

Definition at line 223 of file HistAcc.h.

put1()

template<class T >

void casacore::HistAcc< T >::put1 ( const  T )

private

Accumulate a single value into the histogram.

putBuffer()

template<class T >

void casacore::HistAcc< T >::putBuffer ( const T  v )

private

reset()

template<class T >

void casacore::HistAcc< T >::reset

(

)

Reset the contents of the bins to zero, but retain the current bin definition.

Member Data Documentation

itsAutoDefineMode

template<class T >

Bool casacore::HistAcc< T >::itsAutoDefineMode

private

Definition at line 188 of file HistAcc.h.

itsBinContents

template<class T >

Block<uInt> casacore::HistAcc< T >::itsBinContents

private

Definition at line 182 of file HistAcc.h.

itsBinHighLimit

template<class T >

Block<T> casacore::HistAcc< T >::itsBinHighLimit

private

Definition at line 183 of file HistAcc.h.

itsBuffer

template<class T >

Block<T> casacore::HistAcc< T >::itsBuffer

private

Definition at line 189 of file HistAcc.h.

itsBufferContents

template<class T >

uInt casacore::HistAcc< T >::itsBufferContents

private

Definition at line 190 of file HistAcc.h.

itsStatAcc

template<class T >

StatAcc<T> casacore::HistAcc< T >::itsStatAcc

private

Definition at line 186 of file HistAcc.h.

itsUserDefinedBinWidth

template<class T >

T casacore::HistAcc< T >::itsUserDefinedBinWidth

private

Definition at line 184 of file HistAcc.h.

---

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

• scimath/Mathematics/HistAcc.h