Re: Problem fitting histos

Hi Francesco,

Indeed in addition to the name you need title and number of bins and an indicator that the range should be calculated.

    new TH1F("histo","title",100,0,0)

Rather than:

    TFile *_file0 = TFile::Open("/data/singlepe/Run000470.root");     TTree *tv__tree = (TTree *) gROOT->FindObject("Events");

I recommend:

    TFile *_file0 = TFile::Open("/data/singlepe/Run000470.root");     TTree *tv__tree; _file0->GetObject("Events",tv_tree);

that more explicitly express you intent.

Cheers,
Philippe.

On 1/26/12 2:37 AM, perfetto_at_na.infn.it wrote:
> Hi Philippe,
>
> thanks for your replay, but don't work, now when run the script I got the
> following error:
>
> Error: Can't call TH1D::TH1D("histo") in current scope auto_lin.C:18:
> Possible candidates are...
> (in TH1D)
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(void);
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(const
> char* name,const char* title,Int_t nbinsx,Double_t xlow,Double_t xup);
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(const
> char* name,const char* title,Int_t nbinsx,const Float_t* xbins);
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(const
> char* name,const char* title,Int_t nbinsx,const Double_t* xbins);
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(const
> TVectorD& v);
> /cern/root-5.26/lib/libHist.so -1:-1 0 public: TH1D TH1D::TH1D(const
> TH1D& h1d);
> (in TH1)
> *** Interpreter error recovered ***
>
> Francesco.
>
>> Hi,
>>
>> Try with:
>>
>> TH1D *histo = new TH1D("histo"); //<------ I don't put bin and range
>> because
>>
>> The 'name' is required for the use by TTree::Draw.
>>
>> Philippe.
>>
>> On 1/25/12 11:48 AM, 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
>>> 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 - 17:22:49 CET