Hi,all
A stupid question.
I use the following code to apply the TFractionFitter tool.
TObjArray *mc = new TObjArray(3);
mc->Add(h2);
mc->Add(h3);
mc->Add(h4);
TFractionFitter* fit = new TFractionFitter(h1, mc); // initialise
fit->Constrain(0,0.0,1.0);
fit->Constrain(1,0.0,1.0);
fit->Constrain(2,0.0,1.0);
Int_t status = fit->Fit();
cout << "fit status: " << status << endl;
if (status == 0)
{ // check on fit status
TH1D* result = (TH1D*) fit->GetPlot();
result->SetLineColor(kRed);
result->Draw(“same”);
TH1D* result1=(TH1D*) fit->GetMCPrediction(0);
result1->SetLineColor(kBlue);
result1->SetFillColor(kBlue);
TH1D* result2=(TH1D*) fit->GetMCPrediction(1);
result2->SetLineColor(kYellow);
result2->SetFillColor(kYellow);
TH1D* result3=(TH1D*) fit->GetMCPrediction(2);
result3->SetLineColor(kMagenta);
result3->SetFillColor(kMagenta);
THStack *hs=new THStack("hs","test stacked histograms");
hs->Add(result3);
hs->Add(result2);
hs->Add(result1);
hs->Draw("same");
h1->Draw("e1same");
}
The result I get is as the plot enclosed.
The fit result(red line histogram) describes the data(which is h1 histogram, black points) well.
But the MC THStack result does not describe the data well.
I think the MC THStack one should be the same as the fit result, but it is not the story.
Any idea?
Thanks
W.
tfractest_1.pdf (17.6 KB)