Hi All,
I don't be able to fitting and save some variables of a tree that I put in
a histo.
The following the part of my code that should do this... But when I run it:
.L Fit.C
fit_peak()
I got the following result:
<TCanvas::MakeDefCanvas>: created default TCanvas with name c1
Warning in <Fit>: Fit data is empty
0
Warning in <Fit>: Fit data is empty
0
Warning in <Fit>: Fit data is empty
0
Warning in <Fit>: Fit data is empty
0
and ROOT open an empty canvas.
Is there anyone can help me ?
I use ROOT 5.26/00 on Scientific Linux 5
Thanks in advance
Francesco.
#include <iostream>
#include <fstream>
#include <iomanip>
#include <TH1>
void fit_peak() {
ofstream out;
...
TFile *_file0 = TFile::Open("/data/singlepe/Run000470.root");
TTree *tv__tree = (TTree *) gROOT->FindObject("Events");
Double_t res_fit;
TF1 *f = new TF1("f","gaus");
for (Int_t i = 0; i < 4; i++) {
TH1D *histo = new TH1D(); // <------ I don't put bin and range because
I do not know in
whatrange
tv__tree->Draw( Form("-channels[%d].regions[0].integral >> histo", i) );
histo->Fit(f);
res_fit = f->GetParameter(i);
out.open("result_fit_from_to.txt", ios::out | ios::app);
out << setw(8) << setprecision(5) << f->GetParameter(1); out << setw(8) << setprecision(5) << f->GetParameter(2); out << setw(8) << setprecision(5) << f->GetParameter(3); out << endl;
out.close();
histo->Delete();
}
....
....
}
Received on Wed Jan 25 2012 - 18:48:13 CET
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