A general description of the Histogram library is documented in the class TH1.

ROOT supports the following histogram types:

1-D histograms:
- TH1C : histograms with one byte per channel. Maximum bin content = 127
- TH1S : histograms with one short per channel. Maximum bin content = 32767
- TH1I : histograms with one int per channel. Maximum bin content = 2147483647
- TH1F : histograms with one float per channel. Maximum precision 7 digits
- TH1D : histograms with one double per channel. Maximum precision 14 digits
2-D histograms:
- TH2C : histograms with one byte per channel. Maximum bin content = 127
- TH2S : histograms with one short per channel. Maximum bin content = 32767
- TH2I : histograms with one int per channel. Maximum bin content = 2147483647
- TH2F : histograms with one float per channel. Maximum precision 7 digits
- TH2D : histograms with one double per channel. Maximum precision 14 digits
3-D histograms:
- TH3C : histograms with one byte per channel. Maximum bin content = 127
- TH3S : histograms with one short per channel. Maximum bin content = 32767
- TH3I : histograms with one int per channel. Maximum bin content = 2147483647
- TH3F : histograms with one float per channel. Maximum precision 7 digits
- TH3D : histograms with one double per channel. Maximum precision 14 digits

Collaboration diagram for Histogram Library:

Modules
	Histograms and graphs painting classes.

	Advanced spectra processing classes.

Classes
class	THbookBranch
	HBOOK Branch. More...

class	THbookFile
	This class is an interface to the Hbook objects in Hbook files. More...

class	THbookKey
	HBOOK Key. More...

class	THbookTree
	A wrapper class supporting Hbook ntuples (CWN and RWN). More...

class	TAxis
	Class to manage histogram axis. More...

class	TBackCompFitter
	Backward compatible implementation of TVirtualFitter. More...

class	TBinomialEfficiencyFitter
	Binomial fitter for the division of two histograms. More...

class	TConfidenceLevel
	Class to compute 95% CL limits. More...

class	TEfficiency
	Class to handle efficiency histograms. More...

class	TF1
	1-Dim function class More...

class	TF12
	A projection of a TF2 along X or Y. More...

class	TF1Convolution
	Class wrapping convolution of two functions. More...

class	TF1NormSum
	Class adding two functions: c1f1+c2f2. More...

class	TF2
	A 2-Dim function with parameters. More...

class	TF3
	A 3-Dim function with parameters. More...

class	TFitResult
	Extends the ROOT::Fit::Result class with a TNamed inheritance providing easy possibility for I/O. More...

class	TFormula
	The F O R M U L A class. More...

class	TGraph
	A Graph is a graphics object made of two arrays X and Y with npoints each. More...

class	TGraph2D
	Graphics object made of three arrays X, Y and Z with the same number of points each. More...

class	TGraph2DErrors
	Graph 2D class with errors. More...

class	TGraphAsymmErrors
	TGraph with assymetric error bars. More...

class	TGraphBentErrors
	A TGraphBentErrors is a TGraph with bent, assymetric error bars. More...

class	TGraphDelaunay
	TGraphDelaunay generates a Delaunay triangulation of a TGraph2D. More...

class	TGraphDelaunay2D
	TGraphDelaunay2D generates a Delaunay triangulation of a TGraph2D. More...

class	TGraphErrors
	A TGraphErrors is a TGraph with error bars. More...

class	TGraphSmooth
	A helper class to smooth TGraph. More...

class	TGraphTime
	TGraphTime is used to draw a set of objects evolving with nsteps in time between tmin and tmax. More...

class	TH1C
	1-D histogram with a bype per channel (see TH1 documentation) More...

class	TH1S
	1-D histogram with a short per channel (see TH1 documentation) More...

class	TH1I
	1-D histogram with a int per channel (see TH1 documentation)} More...

class	TH1F
	1-D histogram with a float per channel (see TH1 documentation)} More...

class	TH1D
	1-D histogram with a double per channel (see TH1 documentation)} More...

class	TH2C
	2-D histogram with a bype per channel (see TH1 documentation) More...

class	TH2S
	2-D histogram with a short per channel (see TH1 documentation) More...

class	TH2I
	2-D histogram with a int per channel (see TH1 documentation)} More...

class	TH2F
	2-D histogram with a float per channel (see TH1 documentation)} More...

class	TH2D
	2-D histogram with a double per channel (see TH1 documentation)} More...

class	TH2Poly
	2D Histogram with Polygonal Bins More...

class	TH2PolyBin
	Helper class to represent a bin in the TH2Poly histogram. More...

class	TH3C
	3-D histogram with a bype per channel (see TH1 documentation) More...

class	TH3S
	3-D histogram with a short per channel (see TH1 documentation) More...

class	TH3I
	3-D histogram with a int per channel (see TH1 documentation)} More...

class	TH3F
	3-D histogram with a float per channel (see TH1 documentation)} More...

class	TH3D
	3-D histogram with a double per channel (see TH1 documentation)} More...

class	TH3
	The 3-D histogram classes derived from the 1-D histogram classes. More...

class	THLimitsFinder
	Class to find nice axis limits. More...

class	THn
	Multidimensional histogram. More...

class	THnBase
	Multidimensional histogram base. More...

class	THnSparse
	Efficient multidimensional histogram. More...

class	THStack
	The Histogram stack class. More...

class	TKDE
	Kernel Density Estimation class. More...

class	TLimit
	Algorithm to compute 95% C.L. More...

class	TMultiDimFit
	Multidimensional Fits in ROOT. More...

class	TMultiGraph
	A TMultiGraph is a collection of TGraph (or derived) objects. More...

class	TPolyMarker
	A PolyMarker is defined by an array on N points in a 2-D space. More...

class	TPrincipal
	Principal Components Analysis (PCA) More...

class	TProfile
	Profile Historam. More...

class	TProfile2D
	Profile2D histograms are used to display the mean value of Z and its RMS for each cell in X,Y. More...

class	TProfile3D
	Profile3D histograms are used to display the mean value of T and its RMS for each cell in X,Y,Z. More...

class	TSpline
	Base class for spline implementation containing the Draw/Paint methods //. More...

class	TSVDUnfold
	SVD Approach to Data Unfolding. More...

class	TUnfold
	TUnfold is used to decompose a measurement y into several sources x given the measurement uncertainties and a matrix of migrations A. More...

class	TUnfoldBinning
	This class serves as a container of analysis bins analysis bins are specified by defining the axes of a distribution. More...

class	TUnfoldSys
	TUnfold is used to decompose a measurement y into several sources x given the measurement uncertainties and a matrix of migrations A. More...

class	TVirtualFitter
	Abstract Base Class for Fitting. More...

class	TVirtualGraphPainter
	Abstract interface to a histogram painter. More...

class	TVirtualHistPainter
	Abstract interface to a histogram painter. More...

Modules

Classes