Example of candle plot showing the whiskers definition.
Author: Georg Troska
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, March 19, 2024 at 07:10 PM.
auto c1 = new TCanvas("c1","Candle Presets",700,800);
c1->Divide(1,2);
auto rng = new TRandom();
auto h1 = new TH2I("h1","Gaus",100,-5,5,1,0,1);
auto h2 = new TH1I("h2","Gaus",100,-5,5);
h1->GetXaxis()->SetTitle("Standard deviation #sigma");
h2->GetXaxis()->SetTitle("Standard deviation #sigma");
h2->GetYaxis()->SetTitle("dN/d#sigma");
float myRand;
for (int i = 0; i < 100000; i++) {
myRand = rng->Gaus(0,1);
h1->Fill(myRand,0);
h2->Fill(myRand);
}
Double_t *q = new Double_t[3];
Double_t *p = new Double_t[3];
q[0] = 0.; q[1] = 0.; q[2] = 0.;
p[0] = 0.25; p[1] = 0.5; p[2] = 0.75;
h2->GetQuantiles(3,q,p);
cout << "Q1 (-25%): " << q[0] << " Median: " << q[1] << " Q3 (+25%): " << q[2] << endl;
double iqr = q[2]-q[0];
auto mygaus_1_middle = new TF1("mygaus_1_middle","gaus",q[0],q[2]);
auto mygaus_1_left = new TF1("mygaus_1_left","gaus",q[0]-1.5*iqr,q[0]);
mygaus_1_left->SetLineColor(kGreen);
auto mygaus_1_right = new TF1("mygaus_1_right","gaus",q[2],q[2]+1.5*iqr);
mygaus_1_right->SetLineColor(kGreen);
c1->cd(1);
h1->SetLineWidth(3);
h1->SetFillStyle(0);
h1->Draw("candley2 scat");
c1->cd(2);
h2->Draw("");
h2->Fit("mygaus_1_left","R");
mygaus_1_left->Draw("same");
auto l3 = new TLine(q[0]-1.5*iqr,0,q[0]-1.5*iqr,mygaus_1_left->Eval(q[0]-1.5*iqr));
l3->SetLineColor(kGreen); l3->SetLineWidth(2); l3->Draw("");
auto l1 = new TLine(q[0] ,0,q[0] ,mygaus_1_left->Eval(q[0]));
l1->SetLineWidth(2); l1->SetLineColor(kGreen); l1->Draw("");
h2->Fit("mygaus_1_right","R","");
mygaus_1_right->Draw("same");
auto l4 = new TLine(q[2]+1.5*iqr,0,q[2]+1.5*iqr,mygaus_1_left->Eval(q[2]+1.5*iqr));
l4->SetLineColor(kGreen); l4->SetLineWidth(2); l4->Draw("");
auto l5 = new TLine(q[2] ,0,q[2] ,mygaus_1_right->Eval(q[2]));
l5->SetLineWidth(2); l5->SetLineColor(kGreen); l5->Draw("");
h2->Fit("mygaus_1_middle","R");
mygaus_1_middle->Draw("same");
Q1 (-25%): -0.675525 Median: 0.00168511 Q3 (+25%): 0.676189 **************************************** Minimizer is Minuit2 / Migrad Chi2 = 11.7941 NDf = 17 Edm = 1.90451e-06 NCalls = 131 Constant = 3728.5 +/- 182.159 Mean = -0.110704 +/- 0.0721072 Sigma = 0.959495 +/- 0.025154 (limited) **************************************** Minimizer is Minuit2 / Migrad Chi2 = 8.0469 NDf = 17 Edm = 1.56503e-05 NCalls = 132 Constant = 4071.09 +/- 244.49 Mean = -0.0289155 +/- 0.087166 Sigma = 1.00961 +/- 0.0288274 (limited) **************************************** Minimizer is Minuit2 / Migrad Chi2 = 6.93238 NDf = 11 Edm = 3.27894e-08 NCalls = 107 Constant = 3970.02 +/- 25.7596 Mean = -0.000189021 +/- 0.0118284 Sigma = 1.02465 +/- 0.0335469 (limited)
In principal one could calculate these values by h2->Integral() as well
TText t;
t.SetTextFont(42);
t.DrawText(0,mygaus_1_middle->Eval(0)/2,"50%");
t.DrawText(-1.5,mygaus_1_middle->Eval(-1.5)/2,"24.65%");
t.DrawText(+1,mygaus_1_middle->Eval(+1.5)/2,"24.65%");
t.DrawText(q[0]-1.5*iqr,1000,Form("%.3f",q[0]-1.5*iqr))->SetTextAngle(90);
t.DrawText(q[2]+1.5*iqr,1000,Form("%.3f",q[2]+1.5*iqr))->SetTextAngle(90);
t.DrawText(q[0],1000,Form("%.3f",q[0]))->SetTextAngle(90);
t.DrawText(q[2],1000,Form("%.3f",q[2]))->SetTextAngle(90);
Draw all canvases
gROOT->GetListOfCanvases()->Draw()
Warning in <THistPainter::MakeChopt>: option SCAT is deprecated.