InternalZGY::HistogramBuilder Class Reference

Collect statistics and histogram for bulk data. More...

#include <histogrambuilder.h>

Public Types
typedef int	size_type
typedef StatisticData::count_type	count_type

Public Member Functions
	HistogramBuilder (size_type _nbins, double _min, double _max)
	HistogramBuilder (const count_type *bins, int nbins, double min, double max, count_type scnt, double ssum, double sssq, double smin, double smax)
HistogramBuilder &	operator+= (const HistogramBuilder &other)
HistogramBuilder &	operator-= (const HistogramBuilder &other)
HistogramBuilder &	operator*= (count_type factor)
bool	operator== (const HistogramBuilder &other) const
bool	operator!= (const HistogramBuilder &other) const
StatisticData	gethiststats () const
template<typename It >
void	add (It begin, It end)
void	scale (double oldmin, double oldmax, double newmin, double newmax)

Detailed Description

Collect statistics and histogram for bulk data.

Note the following caveat with histogram data. The histogram is described by number of bins and a pair of min/max values. It is not obvious whether those values describe the center value of the first and last bin, or whether they are the open ended range representing the whole histogram. I.e. the first value (inclusive) of the first bin and the last value (exclusive) of the last bin. HistogramBuilder uses the former definition.

Constructor & Destructor Documentation

HistogramBuilder() [1/2]

InternalZGY::HistogramBuilder::HistogramBuilder	(	size_type	nbins,
		double	min,
		double	max
	)

Create a new HistogramBuilder.

HistogramBuilder() [2/2]

InternalZGY::HistogramBuilder::HistogramBuilder	(	const count_type *	bins,
		int	nbins,
		double	min,
		double	max,
		count_type	scnt,
		double	ssum,
		double	sssq,
		double	smin,
		double	smax
	)

Copy constructor from a histogram passed as discrete information. Useful for converting from some other histogram type. Always create a fixed-range histogram with the same range and number of bins as the source. If this is not what you need, convert it using operator+=(). The above, below, and infinite counts are left at zero.

Member Function Documentation

add()

template<typename It >

void InternalZGY::HistogramBuilder::add	(	It	begin,
		It	end
	)

Add samples from an iterator to a histogram. If the caller has already calculated statistics from the iterator, those can be passed it so this function doesn't need to do it again.

gethiststats()

StatisticData InternalZGY::HistogramBuilder::gethiststats

(

)

const

Statistics calculated from bins

Calculate statistics directly from the histogram. See the overloaded StatisticData constructor for details. Here we don't know whether the histogram was built from 8-bit data, so we play it safe and assume it wasn't.

operator!=()

bool InternalZGY::HistogramBuilder::operator!=

(

const HistogramBuilder &

other

)

const

See operator== for a description.

operator*=()

HistogramBuilder & InternalZGY::HistogramBuilder::operator*=

(

count_type

factor

)

Multiply HistogramBuilder with a constant N, equivalent to creating a new instance and adding the old one to it N times. N can be negative.

operator+=()

HistogramBuilder & InternalZGY::HistogramBuilder::operator+=

(

const HistogramBuilder &

other

)

Add the samples found in another histogram, just as if the samples had been added one at a time using Add().

operator-=()

HistogramBuilder & InternalZGY::HistogramBuilder::operator-=

(

const HistogramBuilder &

other

)

Subtract the samples found in another histogram, more or less undoing the effect of Add. The min/max range in the statistics might be left showing a too wide range.

operator==()

bool InternalZGY::HistogramBuilder::operator==

(

const HistogramBuilder &

other

)

const

Two histograms are considered equal if they return the same bin count for any input value. In practice there is some slop, as only the center of each bin of either histogram is checked. The statistics information need not match. Nor is there any check that the histograms have the same range or even the same number of bins.

scale()

void InternalZGY::HistogramBuilder::scale	(	double	oldmin,
		double	oldmax,
		double	newmin,
		double	newmax
	)

Calculate the linear transform needed to convert from one range (typically the natural data range of the integral storage type) to the data range that the application wants to see. Then update the histogram and associated statistics so they look like the transform had been done on every single data point before adding it.

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

• impl/histogrambuilder.h
• impl/histogrambuilder.cpp