Histogram smoothing.
Author: Rene Brun
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.
int ipad = 1;
TCanvas * c1 = 0;
Definition of a helper function:
%%cpp -d
void smooth_hist(const char * fname, double xmin, double xmax, int n1, int n2) {
std::cout << "smoothing a " << fname << " histogram" << std::endl;
TH1D * h1 = new TH1D("h1","h1",100,xmin,xmax);
TH1D * h2 = new TH1D("h2","h2",100,xmin,xmax);
h1->FillRandom(fname,n1);
TH1D * h1_s = new TH1D(*h1);
h1_s->SetName("h1_s");
h1_s->Smooth();
h2->FillRandom(fname,n2);
double p1 = h1->Chi2Test(h2,"");
double p2 = h1_s->Chi2Test(h2,"UU");
if (p2 < p1) Error("testSmooth","TH1::Smooth is not working correctly - a worst chi2 is obtained");
std::cout << " chi2 test non-smoothed histo " << p1 << std::endl;
std::cout << " chi2 test smoothed histo " << p2 << std::endl;
double a1 = h1->AndersonDarlingTest(h2);
double a2 = h1_s->AndersonDarlingTest(h2);
std::cout << " AD test non-smoothed histo " << a1 << std::endl;
std::cout << " AD test smoothed histo " << a2 << std::endl;
double k1 = h1->KolmogorovTest(h2);
double k2 = h1_s->KolmogorovTest(h2);
std::cout << " KS test non-smoothed histo " << k1 << std::endl;
std::cout << " KS test smoothed histo " << k2 << std::endl;
c1->cd(ipad++);
h1->Draw("E");
h1_s->SetLineColor(kRed);
h1_s->Draw("same");
h2->Scale(double(n1)/n2);
h2->SetLineColor(kGreen);
h2->Draw("same");
}
Arguments are defined.
int n1 = 1000;
int n2 = 1000000;
TH1::AddDirectory(false);
c1 = new TCanvas();
c1->Divide(1,3);
smooth_hist("gaus",-5,5,n1,n2);
smooth_hist("landau",-5,15,n1,n2);
smooth_hist("expo",-5,0,n1,n2);
smoothing a gaus histogram chi2 test non-smoothed histo 5.15629e-11 chi2 test smoothed histo 1 AD test non-smoothed histo 0.70651 AD test smoothed histo 0.488314 KS test non-smoothed histo 0.933145 KS test smoothed histo 0.770148 smoothing a landau histogram chi2 test non-smoothed histo 0.966464 chi2 test smoothed histo 1 AD test non-smoothed histo 0.553608 AD test smoothed histo 0.332666 KS test non-smoothed histo 0.7146 KS test smoothed histo 0.782846 smoothing a expo histogram chi2 test non-smoothed histo 0.364215 chi2 test smoothed histo 0.999894 AD test non-smoothed histo 0.870351 AD test smoothed histo 0.58522 KS test non-smoothed histo 0.966402 KS test smoothed histo 0.753307
Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event. Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event. Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event. Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event. Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event. Info in <TH1D::Chi2TestX>: There is a bin in h1 with less than 1 event.
Draw all canvases
gROOT->GetListOfCanvases()->Draw()