Normalizing a Histogram
Image produced by .x NormalizeHistogram.C
Two different methods of normalizing histograms
are shown, each with the original histogram.
next to the normalized one.
Author: Advait Dhingra
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Wednesday, April 17, 2024 at 11:13 AM.
std::array<double, 6> binsx{0, 5, 10, 20, 50, 100};
TH1F *orig = new TH1F("orig", "Original histogram before normalization", binsx.size() - 1, &binsx[0]);
gStyle->SetTitleFontSize(0.06);
TRandom2 rand;
Filling histogram with random entries
for (int i = 0; i < 100'000; ++i) {
double r = rand.Rndm() * 100;
orig->Fill(r);
}
TH1F *norm = (TH1F *)orig->Clone("norm");
norm->SetTitle("Normalized Histogram");
Unbalanced braces. This cell was not processed.
Normalizing the Histogram by scaling by 1 / the integral and taking width into account
norm->Scale(1. / norm->Integral(), "width");
input_line_53:2:2: error: reference to overloaded function could not be resolved; did you mean to call it? norm->Scale(1. / norm->Integral(), "width"); ^~~~ /usr/include/c++/9/complex:690:5: note: possible target for call norm(const complex<_Tp>& __z) ^ /usr/include/c++/9/complex:1864:5: note: possible target for call norm(_Tp __x) ^
Drawing everything
TCanvas *c1 = new TCanvas("c1", "Histogram Normalization", 700, 900);
c1->Divide(1, 2);
c1->cd(1);
orig->Draw();
c1->cd(2);
norm->Draw();
input_line_54:8:1: error: reference to overloaded function could not be resolved; did you mean to call it? norm->Draw(); ^~~~ /usr/include/c++/9/complex:690:5: note: possible target for call norm(const complex<_Tp>& __z) ^ /usr/include/c++/9/complex:1864:5: note: possible target for call norm(_Tp __x) ^
Draw all canvases
%jsroot on
gROOT->GetListOfCanvases()->Draw()