Histogram Library

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
  • TH1L : histograms with one long64 per channel. Maximum bin content = 9223372036854775807
  • 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
  • TH2L : histograms with one long64 per channel. Maximum bin content = 9223372036854775807
  • 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
  • TH3L : histograms with one long64 per channel. Maximum bin content = 9223372036854775807
  • TH3F : histograms with one float per channel. Maximum precision 7 digits
  • TH3D : histograms with one double per channel. Maximum precision 14 digits

  See also:

  • The Chapter about the Histogram classes in the Users Guide
  • The Chapter about Fitting Histogram in the Users Guide
  • How to use the Histogram classes
  • How to Merge files with histograms and Trees
  • How to Fit Histograms
  • How to Fit find peaks in histograms
  • How to convert Hbook/PAW files to ROOT

Topics
	Painting classes
	Histogram classes.
	Graph classes.
	Function classes.
	ROOT 7 histogram classes.
	Advanced spectra processing classes.
	TUnfold classes

Classes
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	TFitResult
	Extends the ROOT::Fit::Result class with a TNamed inheritance providing easy possibility for I/O. More...
class	TFormula
	The Formula class. More...
class	ROOT::v5::TFormula
	The FORMULA class (ROOT version 5) More...
class	ROOT::v5::TFormulaPrimitive
	The Formula Primitive class. More...
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	THnBase
	Multidimensional histogram base. More...
class	THnSparse
	Efficient multidimensional histogram. More...
class	TKDE
	Kernel Density Estimation class. More...
class	TLimit
	Legacy Code TLimit is a legacy interface: there will be no bug fixes nor new developments. Therefore it is not recommended to use it in new long-term production code. But, depending on the context, using TLimit might still be a valid solution. Consider switching to RooStats. Algorithm to compute 95% CL limits using the Likelihood ratio semi-bayesian method. More...
class	TMultiDimFit
	Multidimensional Fits in ROOT. More...
class	TPrincipal
	Principal Components Analysis (PCA) More...
class	TProfile2PolyBin
	Helper class to represent a bin in the TProfile2Poly histogram. More...
class	TSpline
	Base class for spline implementation containing the Draw/Paint methods. More...
class	TSpline3
	Class to create third splines to interpolate knots Arbitrary conditions can be introduced for first and second derivatives at beginning and ending points. More...
class	TSpline5
	Class to create quintic natural splines to interpolate knots Arbitrary conditions can be introduced for first and second derivatives using double knots (see BuildCoeff) for more on this. More...
class	TSplinePoly
	Base class for TSpline knot. More...
class	TSplinePoly3
	Class for TSpline3 knot. More...
class	TSplinePoly5
	Class for TSpline5 knot. More...
class	TSVDUnfold
	SVD Approach to Data Unfolding. More...
class	TVirtualFitter
	Abstract Base Class for Fitting. More...