Hello,
I want to draw a function TF1 which gets its arguments from a TTree.
s.th like this:
{
TFile *f = new TFile("test.root"); // open file test.root
TTree *t = (TTree*)f->Get("T"); // get the tree,
TH1F *h1_1 = new TH1F("H1_1","H1_1",80,-0.1,1.1); // declare histogramm
T->Draw("x>>H1_1","y<1 && y>0","",30000); // Draw values from
// tree into H1, x, y are floats in tree
TF1 *fun1 = new TF1("Fun1","pol7",0,1); // decleare a function
H1_1->Fit("Fun1","","",0,1); // do a fit to the distribution of x
// now I want to draw Fun1 as a function of y which is float in the tree
// s.th like T->Draw("Fun1(y):y","y<1 && y>0","",30000);
}
I believe TTreeFormula could help?
Does anybody has an example on how to use TTreeFormula
merci
Dirk
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