Hi,
h2->GetMean(); returns the mean value of teh histogram bins.
To get the value of the parameter "Mean" (2nd parameter of teh fitted
function), do:
h2->GetFunction("gaus")->GetParameter(1);
for more information, see Users Guide and documentation
of TH1::Fit
http://root.cern.ch/root/htmldoc/TH1.html#TH1:Fit
see also examples in the tutorials, eg FittingDemo.C
Rene Brun
On Fri, 29 Aug
2003, ginn gin wrote:
> Hi,
> Thank you for the quick reply. I have changed it
> and it works. Now I tried to do a gaussian fitting and
> get the Mean value for the fit. When I do it as shown
> below, it gives me the Mean value of the histo before
> the fitting. It does not give the Mean value of
> fitting. How can I get this fixed?
>
> Thanks,
>
> Ginn
>
> I use RH 8.0 and ROOT 3.05
> ================= Program ===================
> {
> Double_t ave;
> Int_t i;
>
> TFile f("mpeak.root");
> TH1F *h2= new TH1F("h2","",50,0.,1000);
> gStyle->SetOptFit();
> for( i=6480; i<6500; i++){
> ntuple->Draw("bpul>>h2",Form("btub==55611&&ctub==%d",i);
> h2->Fit("gaus","R","same",0.,1000);
> ave = h2->GetMean();
> cout<<" average : "<<ave<<endl;
> }
> }
> --- Rene Brun <brun@pcbrun.cern.ch> wrote:
> > Hi,
> >
> > Replace the line:
> >
> > ntuple->Draw("bpul>>h2","btub==55611&&ctub==i");
> > by
> >
> >
> ntuple->Draw("bpul>>h2",Form("btub==55611&&ctub==%d",i));
> >
> > Rene Brun
> >
> > On Wed, 27 Aug 2003,
> > ginn gin wrote:
> >
> > > Hi,
> > > I need to open a root file and look for
> > histograms
> > > and get the mean value of each histogram. One of
> > the
> > > cut is each time changing. I need to put this as i
> > and
> > > initialize i in a for loop. Then i is the one of
> > the
> > > value in ntuple->Draw(.....). When I gave ctub ==
> > 6480
> > > without for loop it works. With the for loop i
> > need to
> > > give values for i= 6480,6481 etc. If I run
> > following
> > > it complains about i. How can I get this fixed.
> > Any
> > > hint or help is appreciated.
> > >
> > > Thank you,
> > > gin
> > > =========Here is the program and what is wrong ===
> > >
> > > {
> > > Double_t ave;
> > > Int_t i;
> > >
> > > TFile f("mpeak.root");
> > > TH1F *h2= new TH1F("h2","",50,0.,1000);
> > >
> > > for( i=6480; i<6500; i++){
> > >
> > ntuple->Draw("bpul>>h2","btub==55611&&ctub==i");
> > > ave = h2->GetMean();
> > > cout<<" average : "<<ave<<endl;
> > > }
> > > }
> > >
> > > __________________________________
> > > Do you Yahoo!?
> > > Yahoo! SiteBuilder - Free, easy-to-use web site
> > design software
> > > http://sitebuilder.yahoo.com
> > >
> >
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free, easy-to-use web site design software
> http://sitebuilder.yahoo.com
>
This archive was generated by hypermail 2b29 : Thu Jan 01 2004 - 17:50:15 MET