Dear root experts,
I’m trying to scale a total sum of histograms that I made by using THStack.
What I want to see is a scaled blue histogram instead of the current one. The ratio plot seems to work fine with the scaling. I followed this link but I didn’t get it right!
Any help will be much appreciated. Thanks.
Here’s what I tried:
void scale(){
TCanvas *can =new TCanvas("plot","plot",700,800);
gStyle->SetOptStat(0);
gPad->SetLeftMargin(0.18);
can->SetTickx(1);
can->SetTicky(1);
TPad *pad1 = new TPad("pad1", "pad1", 0.00, 0.33, 1.00, 1.00);
TPad *pad2 = new TPad("pad2", "pad2", 0.00, 0.00, 1.00, 0.33);
THStack *hs = new THStack("hs","");
THStack *hs1 = new THStack("hs1","");
pad1->SetBottomMargin(0.00001);
pad1->SetBorderMode(0);
pad1->SetLeftMargin(0.14);
pad1->SetTickx(1);
pad1->SetTicky(1);
pad2->SetTopMargin(0.00001);
pad2->SetBottomMargin(0.4);
pad2->SetBorderMode(0);
pad2->SetLeftMargin(0.14);
pad2->SetTickx(1);
pad2->SetTicky(1);
gStyle->SetOptTitle(kFALSE);
pad1->Draw();
pad2->Draw();
pad1->cd();
THStack *hstack = new THStack("hstack","Scaling hstack");
TH1F *data = new TH1F("data","",30,0,3);
TH1F *h1 = new TH1F("h1","",30,0,3);
TH1F *h2 = new TH1F("h2","",30,0,3);
TH1F *h3 = new TH1F("h3","",30,0,3);
TH1F *h4 = new TH1F("h4","",30,0,3);
data->FillRandom("gaus",22500);
data->Draw("e");
data->SetMarkerStyle(20);
data->SetMarkerSize(1.2);
data->SetLineColor(kBlack);
data->GetYaxis()->SetTitle("Events ");
//data->GetYaxis()->SetTitleOffset(1.5);
data->GetXaxis()->SetTitleFont(42);
data->GetXaxis()->SetTitleSize(0.04);
data->GetYaxis()->SetLabelSize(0.04);
data->GetYaxis()->SetTitleFont(42);
data->GetYaxis()->SetTitleSize(0.04);
h1->FillRandom("gaus",20000);
//h1->SetFillColor(kRed);
h1->SetMarkerStyle(21);
h1->SetMarkerColor(kRed);
h2->FillRandom("gaus",1500);
h2->SetFillColor(kBlue);
h2->SetMarkerStyle(21);
h2->SetMarkerColor(kBlue);
h3->FillRandom("gaus",1000);
h3->SetFillColor(kGreen);
h3->SetMarkerStyle(21);
h3->SetMarkerColor(kGreen);
hstack->Add(h3);
hstack->Add(h2);
hstack->Add(h1);
// hstack->Add(h4);
hstack->Draw();
data->Draw("e, same");
TH1F *h = new TH1F(*((TH1F *)(hstack->GetStack()->Last())));
double N_of_bkg = h->Integral(7, 30);
double N_of_data = data->Integral(7, 30);
std::cout<<" N of bkg "<<N_of_bkg<<", and "<<"N of data: "<<N_of_data<<". "<<"Ratio Data/SM: "<<N_of_data/N_of_bkg<<std::endl;
h->Scale(N_of_data/N_of_bkg);
TLegend *leg = new TLegend(0.62,0.62,0.76,0.84,NULL,"brNDC");
leg->SetBorderSize(0);
leg->SetTextAlign(12);
leg->SetTextFont(42);
leg->SetTextSize(0.03230543);
leg->SetLineColor(1);
leg->SetLineStyle(1);
leg->SetLineWidth(1);
leg->SetFillColor(0);
leg->SetFillStyle(1001);
leg->AddEntry(data,"Data","P");
leg->AddEntry(h1 ,"p-0-p","f");
leg->AddEntry(h2,"p-1-p","f");
leg->AddEntry(h3,"p-2-p","f");
leg->Draw();
can->Update();
pad2->cd();
// Calculating the sum manuly and then get the ratio plot.
//TH1F* total1=(TH1F*) ttbar->Clone("total1");
//total1->Add(Wt);
//TH1F* total2=(TH1F*) Zjet->Clone("total2");
//total2->Add(Diboson);
//TH1F* total3=(TH1F*) Mis_ID_lepton->Clone("total3");
//total3->Add(total2);
//TH1F* totalMc=(TH1F*) total1->Clone("totalMc");
//totalMc->Add(total3);
for(int l = 0; l< data->GetNbinsX(); l++) {
h4->SetBinContent(l+1, data->GetBinContent(l+1)/h->GetBinContent(l+1));
}
h4->SetLineColor(kPink+9);
h4->GetXaxis()->SetTitle("m_{somthing} [GeV] ");
h4->GetXaxis()->SetLabelSize(0.09);
h4->GetXaxis()->SetTitleSize(0.12);
h4->GetXaxis()->SetTickLength(0.08);
h4->GetXaxis()->SetTitleOffset(1.163);
h4->GetXaxis()->SetTitleFont(42);
h4->GetYaxis()->SetTitle("Data/Mc");
h4->GetYaxis()->SetLabelSize(0.09);
h4->GetYaxis()->SetTitleSize(0.09);
h4->GetYaxis()->SetTitleOffset(0.7);
h4->GetYaxis()->SetNdivisions(404,kTRUE);
h4->SetStats(false);
h4->SetMaximum(1.3);
h4->SetMinimum(0.7);
h4->Draw("histo");
TLine *line = new TLine();
line->SetLineStyle(2);
line->SetLineWidth(1);
line->SetLineColor(kBlack);
line->DrawLine(h4->GetXaxis()->GetXmin(), 1 , h4->GetXaxis()->GetXmax(), 1 );
}
