Adding several histos

Hi all,

I have many files (~70) with the same directories structure and each one contains a lot of histograms (~1000).

I always used hadd.C to merge these files but I've recently added some TH2s (thickly binned) that create a memory problem while merging!

I tried to use the hadd application instead of the script on only 2 files and it worked fine but the memory was anyway almost filled (I don't know what could happen with 70 files)!  

What could be the reason of this high memory usage? Copies of histos created during the adding procedure?

Is there a way to workaround the problem?

I have to run it on different machines with different characteristics so I'm not interested in the high speed but in the low memory usage!  

Thanks a lot for any idea! :-)  

Bye. Received on Fri Nov 16 2007 - 13:03:26 CET