Re: Problem fitting histos

Hi Francesco,

I'd say you should try to run the TTree::Draw() part manually for a single channel and see if your histograms are being filled at all.

Cheers

        Eduard

On Thu, 26 Jan 2012, perfetto_at_na.infn.it wrote:

> Hi Eduard,
>
> thanks for your help, but don't work.
> I always got the same result:
>
> 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
>
> Other ideas ?
>
> Bye
> Francesco
>
> >
> > Hi Francesco,
> >
> >
> > On Wed, 25 Jan 2012, perfetto_at_na.infn.it wrote:
> >
> >> 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
> >
> > You don't need a bin and range, but you do need a name and title. Try
> > this:
> >
> > TH1D *histo = new TH1D(Form("histo%1d",i),"Title",100,1,0); // the bin
> > start is larger than bin end -> this will make binning automatic
> > tv__tree->Draw( Form("-channels[%d].regions[0].integral >> histo%1d",
> > i,i)
> >
> > Should work...
> >
> > Cheers
> > Eduard
> >
> >
> >
> >> I do not know in
> >> what
> >> range
> >> the
> >> histo
> >> lives.
> >>
> >> 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 Thu Jan 26 2012 - 10:24:37 CET