How do you normalize roots?

Different ways of normalizing histograms

1. Method 1: Double_t num = h->GetBinContent(i); Double_t den = h->GetBinWidth(i); Double_t value = 0; if (den!=0) { value = num/den; h->SetBinContent(i,value); }
2. Method 2: Double_t factor = 1.; h->Scale(factor/h->GetEntries());

How do you fill a histogram root?

To fill a histogram following the distribution in an existing histogram you can use the second signature of TH1 ::FillRandom() . Next code snipped assumes that h is an existing histogram ( TH1 ). root[] TH1F h2(“h2″,”Histo from existing histo”,100,-3,3); root[] h2. FillRandom(&h1, 1000);

How can I learn root CERN?

Obtaining the latest ROOT version is straightforward. Just seek the “Pro” version on this webpage http://root.cern.ch/downloading-root. You will find precompiled versions for the different architectures, or the ROOT source code to compile yourself.

What is a profile histogram?

Profile histogram is a histogram where each bin contains the mean of its entries and possibly the corresponding RMS.

What happens when you modify a ttree in root?

In addition, modifying in place a TTree causes a new TTree instance to be written and the previous one to be deleted. For this reasons, ROOT offers the concept of friends for TTree and TChain: if is good practice to rely on friend trees rather than adding a branch manually.

Can you use root to replace two dimensional histograms?

ROOT also supports profile histograms, which constitute an elegant replacement of two-dimensional histograms in many cases. The inter-relation of two measured quantities X and Y can always be visualized with a two-dimensional histogram or scatter-plot.

What can be added to a root tree?

Creates a Tree with name and title. Various kinds of branches can be added to a tree: Variables representing fundamental types, simple classes/structures or list of variables: for example for C or Fortran structures. Any C++ object or collection, provided by the STL or ROOT.