ROOT::THist< DIMENSIONS, PRECISION > Class Template Reference

template<int DIMENSIONS, class PRECISION>
class ROOT::THist< DIMENSIONS, PRECISION >

Histogram class for histograms with DIMENSIONS dimensions, where each bin count is stored by a value of type PRECISION.

A histogram counts occurrences of values or n-dimensional combinations thereof. Contrary to for instance a TTree, a histogram combines adjacent values. The resolution of this combination is defined by the binning, see e.g. http://www.wikiwand.com/en/Histogram

Definition at line 31 of file THist.h.

Public Types
using	ImplBase_t = Detail::THistImplBase< DIMENSIONS, PRECISION >
	The type of the Detail::THistImplBase of this histogram. More...
using	Coord_t = typename ImplBase_t::Coord_t
	The coordinates type: a DIMENSIONS-dimensional std::array of double. More...
using	Weight_t = typename ImplBase_t::Weight_t
	The type of weights (PRECISION) More...
using	FillFunc_t = typename ImplBase_t::FillFunc_t
	Pointer type to HistImpl_t::Fill, for faster access. More...
using	const_iterator = Internal::THistBinIter< Internal::HistIterFullRange_t >

Public Member Functions
	THist ()=default
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>>
	THist (std::array< TAxisConfig, DIMENSIONS > axes, STATISTICS statConfig=STATISTICS())
	Create a histogram from an array of axes (TAxisConfigs) and possibly an initial STATISTICS object. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>>
	THist (std::array< TAxisConfig, DIMENSIONS > axes, std::string_view histTitle, std::array< std::string_view, DIMENSIONS > axisTitles, STATISTICS statConfig=STATISTICS())
	Constructor overload taking histogram and axis titles. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 1>>
	THist (const TAxisConfig &xaxis, STATISTICS statConfig=STATISTICS())
	Constructor overload that's only available for DIMENSIONS == 1. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 1>>
	THist (const TAxisConfig &xaxis, std::string_view histTitle, std::string_view xAxisTitle, STATISTICS statConfig=STATISTICS())
	Constructor overload that's only available for DIMENSIONS == 1, also passing histogram and axis title. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 2>>
	THist (const TAxisConfig &xaxis, const TAxisConfig &yaxis, STATISTICS statConfig=STATISTICS())
	Constructor overload that's only available for DIMENSIONS == 2. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 2>>
	THist (const TAxisConfig &xaxis, const TAxisConfig &yaxis, std::string_view histTitle, std::string_view xAxisTitle, std::string_view yAxisTitle, STATISTICS statConfig=STATISTICS())
	Constructor overload that's only available for DIMENSIONS == 2, also passing histogram and axis titles. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 3>>
	THist (const TAxisConfig &xaxis, const TAxisConfig &yaxis, const TAxisConfig &zaxis, STATISTICS statConfig=STATISTICS())
	Constructor overload that's only available for DIMENSIONS == 3. More...
template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 3>>
	THist (const TAxisConfig &xaxis, const TAxisConfig &yaxis, const TAxisConfig &zaxis, std::string_view histTitle, std::string_view xAxisTitle, std::string_view yAxisTitle, std::string_view zAxisTitle, STATISTICS statConfig=STATISTICS())
ImplBase_t *	GetImpl () const noexcept
	Access the ImplBase_t this THist points to. More...
void	Fill (const Coord_t &x, Weight_t weight=1.) noexcept
	Add weight to the bin containing coordinate x. More...
void	FillN (const std::array_view< Coord_t > xN, const std::array_view< Weight_t > weightN) noexcept
	For each coordinate in xN, add weightN[i] to the bin at coordinate xN[i]. More...
void	FillN (const std::array_view< Coord_t > xN) noexcept
	Convenience overload: FillN() with weight 1. More...
int64_t	GetEntries () const noexcept
	Get the number of entries this histogram was filled with. More...
const_iterator	begin () const
const_iterator	end () const

Static Public Member Functions
static constexpr int	GetNDim () noexcept
	Number of dimensions of the coordinates. More...

Private Attributes
FillFunc_t	fFillFunc = nullptr
	Pinter to THistImpl::Fill() member function. More...
std::unique_ptr< ImplBase_t >	fImpl
	The actual histogram implementation. More...
std::string	fTitle
	Title of this histogram. More...
std::array< std::string, DIMENSIONS >	fAxisTitles
	Title of each axis. More...

Friends
THist	HistFromImpl (std::unique_ptr< ImplBase_t >)
void	swap (THist< DIMENSIONS, PRECISION > &a, THist< DIMENSIONS, PRECISION > &b) noexcept
	Swap two histograms. More...

#include <ROOT/THist.h>

Collaboration diagram for ROOT::THist< DIMENSIONS, PRECISION >:

Member Typedef Documentation

template<int DIMENSIONS, class PRECISION>

using ROOT::THist< DIMENSIONS, PRECISION >::const_iterator = Internal::THistBinIter<Internal::HistIterFullRange_t>

Definition at line 66 of file THist.h.

template<int DIMENSIONS, class PRECISION>

using ROOT::THist< DIMENSIONS, PRECISION >::Coord_t = typename ImplBase_t::Coord_t

The coordinates type: a DIMENSIONS-dimensional std::array of double.

Definition at line 60 of file THist.h.

template<int DIMENSIONS, class PRECISION>

using ROOT::THist< DIMENSIONS, PRECISION >::FillFunc_t = typename ImplBase_t::FillFunc_t

Pointer type to HistImpl_t::Fill, for faster access.

Definition at line 64 of file THist.h.

template<int DIMENSIONS, class PRECISION>

using ROOT::THist< DIMENSIONS, PRECISION >::ImplBase_t = Detail::THistImplBase<DIMENSIONS, PRECISION>

The type of the Detail::THistImplBase of this histogram.

Definition at line 58 of file THist.h.

template<int DIMENSIONS, class PRECISION>

using ROOT::THist< DIMENSIONS, PRECISION >::Weight_t = typename ImplBase_t::Weight_t

The type of weights (PRECISION)

Definition at line 62 of file THist.h.

Constructor & Destructor Documentation

template<int DIMENSIONS, class PRECISION>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( )

default

template<int DIMENSIONS, class PRECISION >

template<class STATISTICS >

ROOT::THist< DIMENSIONS, PRECISION >::THist	(	std::array< TAxisConfig, DIMENSIONS >	axes,
		STATISTICS	statConfig = STATISTICS()
	)

Create a histogram from an array of axes (TAxisConfigs) and possibly an initial STATISTICS object.

The latter is usually just fine when not passed (i.e. default-constructed). Example code:

Construct a 1-dimensional histogram that can be filled with floatss. The axis has 10 bins between 0. and 1. The two outermost sets of curly braces are to reach the initialization of the std::array elements; the inner one is for the initialization of a TAxisCoordinate.

THist<1,float> h1f({{ {10, 0., 1.} }});

Construct a 2-dimensional histogram, with the first axis as before, and the second axis having non-uniform ("irregular") binning, where all bin- edges are specified. As this is itself an array it must be enclosed by double curlies.

THist<2,int> h2i({{ {10, 0., 1.}, {{-1., 0., 1., 10., 100.}} }});  

Definition at line 300 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>>

ROOT::THist< DIMENSIONS, PRECISION >::THist	(	std::array< TAxisConfig, DIMENSIONS >	axes,
		std::string_view	histTitle,
		std::array< std::string_view, DIMENSIONS >	axisTitles,
		STATISTICS	statConfig = STATISTICS()
	)

Constructor overload taking histogram and axis titles.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 1>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, STATISTICS  statConfig = STATISTICS()  )

inline

Constructor overload that's only available for DIMENSIONS == 1.

Definition at line 101 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 1>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, std::string_view  histTitle, std::string_view  xAxisTitle, STATISTICS  statConfig = STATISTICS()  )

inline

Constructor overload that's only available for DIMENSIONS == 1, also passing histogram and axis title.

Definition at line 108 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 2>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, const TAxisConfig &  yaxis, STATISTICS  statConfig = STATISTICS()  )

inline

Constructor overload that's only available for DIMENSIONS == 2.

Definition at line 116 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 2>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, const TAxisConfig &  yaxis, std::string_view  histTitle, std::string_view  xAxisTitle, std::string_view  yAxisTitle, STATISTICS  statConfig = STATISTICS()  )

inline

Constructor overload that's only available for DIMENSIONS == 2, also passing histogram and axis titles.

Definition at line 124 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 3>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, const TAxisConfig &  yaxis, const TAxisConfig &  zaxis, STATISTICS  statConfig = STATISTICS()  )

inline

Constructor overload that's only available for DIMENSIONS == 3.

Definition at line 133 of file THist.h.

template<int DIMENSIONS, class PRECISION>

template<class STATISTICS = THistStatUncertainty<DIMENSIONS, PRECISION>, class = typename std::enable_if<DIMENSIONS == 3>>

ROOT::THist< DIMENSIONS, PRECISION >::THist ( const TAxisConfig &  xaxis, const TAxisConfig &  yaxis, const TAxisConfig &  zaxis, std::string_view  histTitle, std::string_view  xAxisTitle, std::string_view  yAxisTitle, std::string_view  zAxisTitle, STATISTICS  statConfig = STATISTICS()  )

inline

Definition at line 140 of file THist.h.

Member Function Documentation

template<int DIMENSIONS, class PRECISION>

const_iterator ROOT::THist< DIMENSIONS, PRECISION >::begin ( ) const

inline

Definition at line 177 of file THist.h.

template<int DIMENSIONS, class PRECISION>

const_iterator ROOT::THist< DIMENSIONS, PRECISION >::end ( ) const

inline

Definition at line 178 of file THist.h.

template<int DIMENSIONS, class PRECISION>

void ROOT::THist< DIMENSIONS, PRECISION >::Fill ( const Coord_t &  x, Weight_t  weight = 1.  )

inlinenoexcept

Add weight to the bin containing coordinate x.

Definition at line 157 of file THist.h.

Referenced by ROOT::Add().

template<int DIMENSIONS, class PRECISION>

void ROOT::THist< DIMENSIONS, PRECISION >::FillN ( const std::array_view< Coord_t >  xN, const std::array_view< Weight_t >  weightN  )

inlinenoexcept

For each coordinate in xN, add weightN[i] to the bin at coordinate xN[i].

The sizes of xN and weightN must be the same. This is more efficient than many separate calls to Fill().

Definition at line 164 of file THist.h.

template<int DIMENSIONS, class PRECISION>

void ROOT::THist< DIMENSIONS, PRECISION >::FillN ( const std::array_view< Coord_t >  xN )

inlinenoexcept

Convenience overload: FillN() with weight 1.

Definition at line 170 of file THist.h.

template<int DIMENSIONS, class PRECISION>

int64_t ROOT::THist< DIMENSIONS, PRECISION >::GetEntries ( ) const

inlinenoexcept

Get the number of entries this histogram was filled with.

Definition at line 175 of file THist.h.

template<int DIMENSIONS, class PRECISION>

ImplBase_t* ROOT::THist< DIMENSIONS, PRECISION >::GetImpl ( ) const

inlinenoexcept

Access the ImplBase_t this THist points to.

Definition at line 154 of file THist.h.

Referenced by ROOT::Add(), ROOT::THistView< DIMENSIONS, PRECISION >::end(), and ROOT::THistView< DIMENSIONS, PRECISION >::SetRange().

template<int DIMENSIONS, class PRECISION>

static constexpr int ROOT::THist< DIMENSIONS, PRECISION >::GetNDim ( )

inlinestaticnoexcept

Number of dimensions of the coordinates.

Definition at line 151 of file THist.h.

Friends And Related Function Documentation

template<int DIMENSIONS, class PRECISION>

THist HistFromImpl ( std::unique_ptr< ImplBase_t >  )

friend

template<int DIMENSIONS, class PRECISION>

void swap ( THist< DIMENSIONS, PRECISION > &  a, THist< DIMENSIONS, PRECISION > &  b  )

friend

Swap two histograms.

Very efficient; swaps the fImpl pointers.

Definition at line 196 of file THist.h.

Member Data Documentation

template<int DIMENSIONS, class PRECISION>

std::array<std::string, DIMENSIONS> ROOT::THist< DIMENSIONS, PRECISION >::fAxisTitles

private

Title of each axis.

Definition at line 184 of file THist.h.

template<int DIMENSIONS, class PRECISION>

FillFunc_t ROOT::THist< DIMENSIONS, PRECISION >::fFillFunc = nullptr

private

Pinter to THistImpl::Fill() member function.

Definition at line 181 of file THist.h.

Referenced by ROOT::THist< DIMENSIONS, PRECISION >::Fill(), and ROOT::HistFromImpl().

template<int DIMENSIONS, class PRECISION>

std::unique_ptr<ImplBase_t> ROOT::THist< DIMENSIONS, PRECISION >::fImpl

private

The actual histogram implementation.

Definition at line 182 of file THist.h.

Referenced by ROOT::THist< DIMENSIONS, PRECISION >::end(), ROOT::THist< DIMENSIONS, PRECISION >::Fill(), ROOT::THist< DIMENSIONS, PRECISION >::FillN(), ROOT::THist< DIMENSIONS, PRECISION >::GetEntries(), ROOT::THist< DIMENSIONS, PRECISION >::GetImpl(), and ROOT::HistFromImpl().

template<int DIMENSIONS, class PRECISION>

std::string ROOT::THist< DIMENSIONS, PRECISION >::fTitle

private

Title of this histogram.

Definition at line 183 of file THist.h.

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

• hist/hist/v7/inc/ROOT/THist.h