Re: [ROOT] chaining/efficiency query

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Sep 12 2003 - 16:17:48 MEST


Hi Ed,

Could you replace your TChain->Add statement by
chain->AddFile(pre+numPrefix+num+post,TChain::kBigNumber);

It could be that your final string contains one or more character interpreted as
a regular expression by TChain::Add.

Let me know

Rene Brun

Edward Moyse wrote:
> 
> The files are about 4 Mb each.
> Per file it seems (subjectively) to be going quicker now ... about 2-4s per
> file. This is just chaining them though ... so it's going to take 2 hours
> before it even starts running.
> 
> I have a (crude) loop like below:
> 
> for (Int_t i =0 ; i<numberOfFiles ; ++i){
> TString num="";
> num+=i;
> TString numPrefix="";
> for (Int_t j = 0 ; j < (sizeOfNum-num.Length() ) ; ++j) numPrefix+="0";
> chain->Add(pre+numPrefix+num+post);
> }
> 
> and
> pre="rfio:/castor/cern.ch/atlas/transfer/emoyse/dc1.002000.lumi02.recon.010._";
> post =".hlt.pythia_jet_17.root";
> sizeOfNum=5;
> 
> Even if this loop is sub-optimal (which I can quite believe) I don't see that
> it can make that much difference.
> 
> Oh, and I'm using the latest version 3.05.07.
> 
> Ed
> 
> On Friday 12 September 2003 3:23 pm, Rene Brun wrote:
> > Ed,
> >
> > How big are your files? 1 Mbyte, 100 MBytes, 1 GByte ?
> > How long does it take to process one single file?
> > TChain should not add any overhead.
> > Which version are you using?
> >
> > Rene Brun



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