This script is a slightly modified version of hsum.C.
Uncomment the two c1->Print(...); lines in order to produce
an animated gif file. The option "++" makes an infinite animation.
The animated file hsumanim.gif can be visualized within a web browser
Author: Rene Brun, Valeriy Onuchin
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Thursday, July 17, 2025 at 05:14 AM.
auto c1 = new TCanvas("c1", "The HSUM example", 200, 10, 600, 400);
c1->SetGrid();
gBenchmark->Start("hsum");
Create some histograms.
auto total = new TH1F("total", "This is the total distribution", 100, -4, 4);
auto main = new TH1F("main", "Main contributor", 100, -4, 4);
auto s1 = new TH1F("s1", "This is the first signal", 100, -4, 4);
auto s2 = new TH1F("s2", "This is the second signal", 100, -4, 4);
total->Sumw2(); // this makes sure that the sum of squares of weights will be stored
total->SetMarkerStyle(21);
total->SetMarkerSize(0.7);
main->SetFillColor(16);
s1->SetFillColor(42);
s2->SetFillColor(46);
TSlider *slider = 0;
gSystem->Unlink("hsumanim.gif"); // delete old file
Fill histograms randomly
gRandom->SetSeed();
const Int_t kUPDATE = 500;
Float_t xs1, xs2, xmain;
Int_t gifcnt = 0;
for (Int_t i = 0; i < 10000; i++) {
xmain = gRandom->Gaus(-1, 1.5);
xs1 = gRandom->Gaus(-0.5, 0.5);
xs2 = gRandom->Landau(1, 0.15);
main->Fill(xmain);
s1->Fill(xs1, 0.3);
s2->Fill(xs2, 0.2);
total->Fill(xmain);
total->Fill(xs1, 0.3);
total->Fill(xs2, 0.2);
if (i && (i % kUPDATE) == 0) {
if (i == kUPDATE) {
total->Draw("e1p");
main->Draw("same");
s1->Draw("same");
s2->Draw("same");
c1->Update();
slider = new TSlider("slider", "test", 4.2, 0, 4.6, total->GetMaximum(), 38);
slider->SetFillColor(46);
}
if (slider)
slider->SetRange(0, Float_t(i) / 10000.);
c1->Modified();
c1->Update();
if (gROOT->IsBatch()) {
// c1->Print("hsumanim.gif+");
printf("i = %d\n", i);
} else {
if (gSystem->ProcessEvents())
break;
}
}
}
slider->SetRange(0, 1);
total->Draw("sameaxis"); // to redraw axis hidden by the fill area
c1->Modified();
i = 500 i = 1000 i = 1500 i = 2000 i = 2500 i = 3000 i = 3500 i = 4000 i = 4500 i = 5000 i = 5500 i = 6000 i = 6500 i = 7000 i = 7500 i = 8000 i = 8500 i = 9000 i = 9500
c1->Print("hsumanim.gif++")
gBenchmark->Show("hsum");
hsum : Real Time = 0.92 seconds Cpu Time = 0.41 seconds
Draw all canvases
gROOT->GetListOfCanvases()->Draw()