The inter-relation of two measured quantities X and Y can always be visualized with a two-dimensional histogram or scatter-plot. ROOT also supports profile histograms, which constitute an elegant replacement of two-dimensional histograms in many cases. TH1D, TH2D and TH3D contain one double per bin (maximum precision = 14 digits). TH1F, TH2F and TH3F contain one float per bin (maximum precision = 7 digits). TH1I, TH2I and TH3I contain one integer per bin (maximum bin content = 2 147 483 647). TH1S, TH2S and TH3S contain one short per bin (maximum bin content = 65 535).

TH1C, TH2C and TH3C contain one byte per bin (maximum bin content = 255) The histogram classes are split into further categories, depending on the set of possible bin values: Separate concrete classes are provided for one-dimensional, two-dimensional and three-dimensional classes. ROOT supports histograms up to three dimensions. These are covered in the chapter “Input/Output”. Some of the examples have graphics commands that may look unfamiliar to you. We have put this chapter ahead of the graphics chapter so that you can begin working with histograms as soon as possible. We begin with an overview of the histogram classes, after which we provide instructions and examples on the histogram features. This chapter covers the functionality of the histogram classes.

If you think some information should be imported in the ROOT Reference Guide or in the ROOT Manual, please post your request to the ROOT Forum or via a Github Issue. Instead please refer to the ROOT Reference Guide and the ROOT Manual. Some part might be obsolete or wrong, some part might be missing but still some valuable information can be found there. WARNING: This documentation is not maintained anymore. 5.13 Important note on returned statistics ( GetMean, GetStdDev, etc.).5.11 Saving/Reading Histograms to/from a File.

Histogram dim3 grid