Re: Merging TNtuples from different files in one ROOT file

From: Matthias Kirsch <mkirsch_at_fnal.gov>
Date: Wed, 24 Oct 2007 11:44:56 +0200


Dear Rene,

thank you for your suggestion. It worked!

Best,

        Matthias

Rene Brun wrote:

> In your version using TChain, could you replace the statement:
> ch.Merge("newfile.root")
> by
> ch.Merge("newfile.root","fast")
> 
> Rene Brun
> 
> Matthias Kirsch wrote:

>> Dear ROOTers,
>>
>> I have problems merging several ROOT files into one. Each of the eight
>> files contains an TNtuple with approx. 260 variables. They all have
>> the same name. I have already tried several methods, TFileMerger,
>> hadd, TChain. All these methods work fine, if I only use three or four
>> files. But trying to merge all eight files, I get error messages. The
>> logfile in the attachment shows two interactive attempts using ROOT
>> 5.12/00e. The input files were created with this ROOT version. I also
>> tried to merge the files with using the latest version 5.17/04, but
>> also without success.
>> Is this because of the input size of the files (summed up approx. 80
>> MB)? Or because of the number of variables? I have already used the
>> same methods to merge more than 100 smaller files successfully. Any
>> ideas what might cause this problems?
>>
>> Thanks for your help!
>>
>> Cheers,
>> Matthias

> Received on Wed Oct 24 2007 - 11:45:18 CEST

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