I have met an issue with the ROOT.TFileMerger.
When I set SetFastMethod(True) to merge several files together, it collects only half of the events.
When I use hadd instead, it will show full events(93 events). And when I turn off SetFastMethod to be false, ROOT.TFileMerger collects full events as well.
So could anyone take a look what happened on the SetFastMethod(True)? Actually hard to detect this kind issue and may cause unrealized problems when doing MC/data comparison.
ROOT Version: ROOT 6.10/04
Platform: Not Provided
Compiler: Not Provided