template<typename BinContentType>
class ROOT::Experimental::RHistEngine< BinContentType >

A histogram data structure to bin data along multiple dimensions.

Every call to Fill bins the data according to the axis configuration and increments the bin content:

ROOT::Experimental::RHistEngine<int> hist(10, 5, 15);
hist.Fill(8.5);
// hist.GetBinContent(ROOT::Experimental::RBinIndex(3)) will return 1

The class is templated on the bin content type. For counting, as in the example above, it may be an integer type such as int or long. Narrower types such as unsigned char or short are supported, but may overflow due to their limited range and must be used with care. For weighted filling, the bin content type must be a floating-point type such as float or double. Note that float has a limited significant precision of 24 bits.

An object can have arbitrary dimensionality determined at run-time. The axis configuration is passed as a vector of RAxisVariant:

std::vector<ROOT::Experimental::RAxisVariant> axes;
axes.push_back(ROOT::Experimental::RRegularAxis(10, 5, 15));
axes.push_back(ROOT::Experimental::RVariableBinAxis({1, 10, 100, 1000}));
ROOT::Experimental::RHistEngine<int> hist(axes);
// hist.GetNDimensions() will return 2

Warning: This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback is welcome!

Definition at line 55 of file RHistEngine.hxx.

Public Member Functions
	RHistEngine (const RHistEngine< BinContentType > &)=delete

	RHistEngine (RHistEngine< BinContentType > &&)=default

	RHistEngine (std::size_t nNormalBins, double low, double high)
	Construct a one-dimensional histogram engine with a regular axis.

	RHistEngine (std::vector< RAxisVariant > axes)
	Construct a histogram engine.

	~RHistEngine ()=default

template<typename... A>
void	Fill (const A &...args)
	Fill an entry into the histogram.

template<typename... A>
void	Fill (const std::tuple< A... > &args)
	Fill an entry into the histogram.

const std::vector< RAxisVariant > &	GetAxes () const

template<typename... A>
const BinContentType &	GetBinContent (const A &...args) const
	Get the content of a single bin.

template<std::size_t N>
const BinContentType &	GetBinContent (const std::array< RBinIndex, N > &indices) const
	Get the content of a single bin.

std::size_t	GetNDimensions () const

std::size_t	GetTotalNBins () const

RHistEngine< BinContentType > &	operator= (const RHistEngine< BinContentType > &)=delete

RHistEngine< BinContentType > &	operator= (RHistEngine< BinContentType > &&)=default

void	Streamer (TBuffer &)
	ROOT Streamer function to throw when trying to store an object of this class.

Private Attributes
Internal::RAxes	fAxes
	The axis configuration for this histogram. Relevant methods are forwarded from the public interface.

std::vector< BinContentType >	fBinContents
	The bin contents for this histogram.

[in]	nNormalBins	the number of normal bins, must be > 0
[in]	low	the lower end of the axis interval (inclusive)
[in]	high	the upper end of the axis interval (exclusive), must be > low

Public Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ RHistEngine() [1/4]

◆ RHistEngine() [2/4]

◆ RHistEngine() [3/4]

◆ RHistEngine() [4/4]

◆ ~RHistEngine()

Member Function Documentation

◆ Fill() [1/2]

◆ Fill() [2/2]

◆ GetAxes()

◆ GetBinContent() [1/2]

◆ GetBinContent() [2/2]

◆ GetNDimensions()

◆ GetTotalNBins()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ Streamer()

Member Data Documentation

◆ fAxes

◆ fBinContents