Re: MakeClass()

From: Monika Sharma <monika_at_rcf.rhic.bnl.gov>
Date: Mon, 05 Feb 2007 14:29:49 +0530

Hi Rene,

Thank you for quick answer. I tried it but I am facing a strange problem.

Following is what I did recently :
void Pmd_cucu_analysis()
{

  TChain chain("PmdNano");

  chain.Add("PMD_Nanodst_feb4_540Kevts.root");
  chain.Add("PMD_Nanodst_feb4_540Kevts_1.root");
  chain.MakeClass("PMD");

}

It does generate PMD.C and PMD.h. However when I try to read the number of events in PMD.C, it gives me a very large number of events. Which are not actually present intotality in the above two mentioned rootfiles.

For example :
Following is the output I get when I execute PMD.C

root.exe [1] .L PMD.C
root.exe [2] PMD t
root.exe [3] t.Loop()

Total events = 1234567890

Warning in <TClass::TClass>: no dictionary for class PmdEvent is available
Warning in <TClass::TClass>: no dictionary for class PmdCluster is available
Warning in <TClass::TClass>: no dictionary for class PmdHit is available
Warning in <TClass::TClass>: no dictionary for class PmdTrack is available

root.exe [4] .q

But when I try to see the number of events indiviually from the rootfiles, this is what I get :

root.exe [0]
Attaching file PMD_Nanodst_feb4_540Kevts.root as _file0...

Warning in <TClass::TClass>: no dictionary for class PmdEvent is available
Warning in <TClass::TClass>: no dictionary for class PmdCluster is available
Warning in <TClass::TClass>: no dictionary for class PmdHit is available
Warning in <TClass::TClass>: no dictionary for class PmdTrack is available

root.exe [1] PmdNano->GetEntries()
(const Long64_t)367860
root.exe [2] .q

And :
root.exe [0]
Attaching file PMD_Nanodst_feb4_540Kevts_1.root as _file0...

Warning in <TClass::TClass>: no dictionary for class PmdEvent is available
Warning in <TClass::TClass>: no dictionary for class PmdCluster is available
Warning in <TClass::TClass>: no dictionary for class PmdHit is available
Warning in <TClass::TClass>: no dictionary for class PmdTrack is available

root.exe [1] PmdNano->GetEntries()
(const Long64_t)406344
root.exe [2] .q

So I expect a total of 774204 events from PMD.C (Because this is the actual number
of events present in the rootfiles). Is there any obvious mistake that I am making.

Thanks in advance.
Regards
Monika

Rene Brun wrote:

> Hi Monika,
>
> You should use a TChain to process a collection of files
>
> TChain chain("VW");
> chain.Add("filename_*.root");
> chain.MakeClass("something");
>
> Rene Brun
>
> Monika Sharma wrote:
>
>>
>> Hi Rooters,
>>
>> I am trying to use MakeClass function to read a .root file.
>> Following is a typical example of what I am doing :
>>
>> ========================================
>> void analysis()
>> {
>>
>> TFile *f = new TFile("Event_transport.root");
>> TTree *v = (TTree*)f->Get("VW");
>> f->ls();
>>
>> v->MakeClass("something");
>> }
>> =========================================
>>
>> This generates a .C and a .h file, which works fine for me.
>> But now my aim is to increase statistics. Therefore I have two rootfiles
>> each of ~2 GB size, as a result I cannot merge them any further.
>>
>> I wanted to ask is there anyway that I can still use MakeClass function
>> to read these rootfiles together which would generate one .C and .h file
>> so that I have double the statistics.
>>
>> I tried doing
>> =============================================
>> void analysis()
>> {
>>
>> for(Int_t nFiles=0; nFiles<2; nFiles++)
>> {
>> char fname[150];
>> sprintf(fname,"filename_%d.root",nFiles);
>> cout<<endl;
>> printf(fname,"filename_%d.root",nFiles);
>> TFile *file = new TFile(fname,"r");
>> TTree *P = (TTree*)file->Get("VW");
>> file->ls();
>> }
>> P->MakeClass("something");
>> }
>> =====================================================
>>
>> But the above method generates .C and .h files taking the last
>> rootfile as
>> the input.
>>
>> Thanks in advance.
>> Monika
>
Received on Mon Feb 05 2007 - 10:00:32 CET