Byte count too large error while copying histogram

Newbie
1

Hi. I have two root files containing TH3F histograms.
Interior.root
Exterior.root

I want to copy the TH3F histograms from both the above files to a new file Combined.root
I was able to do so earlier when the histograms had fewer bins but recently I modified the histograms to have almost twice the number of bins and now I get this error.

Error in <TBufferFile::CheckByteCount>: object of class TH3F read too many bytes: 1162592650 instead of 88850826
Warning in <TBufferFile::CheckByteCount>: TH3F::Streamer() not in sync with data on file Interior.root, fix Streamer()
Error in <TBufferFile::WriteByteCount>: bytecount too large (more than 1073741822)

Is there a way to fix this?

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ROOT Version: 6.16.00
Platform: Ubuntu
Compiler: Not Provided

2

ROOT Forum → Search → 1073741822

3

I read through the search results and a lot of replies point out to the 1Gb limit of the RooDataSet.
Maybe I am too much of a newbie but I have not explicitly used RooDataSet.

Here is the code I used to merge the histograms

int main(){
  TString fileName = "Combined.root";

  TFile *outFile = new TFile(fileName,"recreate");
  

  TString dir = "/path/to/file";
  
  TString inFileNameTH3Dint = "Interior.root";
  TString inFileNameTH3Dintextended = "Exterior.root";

  TH3F* mapint = nullptr;
  TH3F* mapintextended = nullptr;

  TFile* fileTH3Dint = TFile::Open(dir+inFileNameTH3Dint);
  fileTH3Dint->GetObject("IntHistName",mapint);
  mapint->SetNameTitle("IntHistName","IntHistName");
  

  TFile* fileTH3Dintextended = TFile::Open(dir+inFileNameTH3Dintextended);  
  fileTH3Dintextended->GetObject("IntExtendedHistName",mapintextended);  
  mapintextended->SetNameTitle("IntExtendedHistName","IntExtendedHistName");



  outFile->cd();
  mapint->Write();
  mapintextended->Write();
 
 
  outFile->Close();
  cout<<"root -l "<<fileName<<endl;
}

Additionally, when I try to open the root file Combined.root I get this error and warning message but I am able to slice and plot the histogram using Project3D. So I am not really sure what’s going on.

root [1] TH3F *h1 = (TH3F*) _file0->Get("IntExtendedHistName")
Error in <TBufferFile::CheckByteCount>: object of class TH3F read too many bytes: 1162592650 instead of 88850826
Warning in <TBufferFile::CheckByteCount>: TH3F::Streamer() not in sync with data on file Combined.root, fix Streamer()
(TH3F *) 0x556b6b08e300

Apologies for inconvenience.

4

Hi @rushabhgala,

Alternatively, you should be able to use hadd to merge your .root files. In regards to the warning that you are facing, I am inviting @pcanal to this topic, as I’m sure he can shed some light on this.

Cheers,
J.

5

Maybe you are facing this bug (check which ROOT versions produced your files, which versions you use to read them, and do not use the versions known to be broken):