I am writing a macro where I wish to read histograms from 1000 files and add them together. I open each file at the time in a loop using:
TFile *myFile = new TFile();
myFile->Open(fileName,“read”);
From the file I copy two histograms (I don’t think this is relevant but) using the ROOT feature that whenever a file is opened you automatically enter this file:
h_Ptmp = new TH1F(*h_primaryElectronFluenceSpectrum);
h_Stmp = new TH1F(*h_scatterElectronFluenceSpectrum);
Finally I close the file and delete the myFile object (at the end of the loop)
myFile->Close();
delete myFile;
However, after some 938 files ROOT crashes telling me that there are too many open files. How can this be? I only open one file at the time and I also close it afterwards? I did some manual testing with cint and also there experienced that even if a TFile is close and the pointer deleted the command “.ls” will still print what is inside the file.
Help would be most appreciated, my Ph.D depends on this merge
you should simply call TFile::Open(…), not new TFile(). And even better yet would be to use hadd from $ROOTSYS/bin. You call it as “hadd out.root in1.root in2.root …”
I have also tried this, but unfortunately it doesn’t work either. I have slimmed my macro down to a minimum (see below). This crashed after 994 files ( I want 1000). I do not wish to use hadd since I am manipulating the histos.
/Karin
PS
I use ROOT 5.18 on Ubuntu 9.10
void runSpectrumBAM(){
int iM,iR;
int nR = 500;
char material[30];
char folder[1000];
char suffix[400];
char fluence[1000];
TH1F *h_Ptmp;
TH1F *h_Stmp;
TFile fluenceFile;
gROOT->Reset();
sprintf(folder,"/media/FREECOM\ HDD/DATA/Emax8MeV/WithoutPSF");
//Loop over material
for(iM=0; iM<2; iM++){
//Loop over runs
for(iR=0 ; iR<nR ; iR++){
if(iM==0){
sprintf(material,"Water");
sprintf(suffix,"%u%03d",1,iR);
}
else{
sprintf(material,"EFD_10cm");
sprintf(suffix,"%u%03d",2,iR);
}
//print file-name
sprintf(fluence,"%s/plots/spectra/histos/histos_Spectrum_%s_xCoord_0cm_yCoord_0cm_depth_10.05cm_%s.root",
folder,material,suffix);
fluenceFile.Open(fluence,"read");
cout<<"* Loading fluence file: "<<fluence<<endl;
//Copy histograms of interest depending on input parameter (either electron or photon)
h_Ptmp = new TH1F(*h_primaryElectronFluenceSpectrum);
h_Stmp = new TH1F(*h_scatterElectronFluenceSpectrum);
fluenceFile.Close();
}//iR
}//iM
}//end
never ever call gROOT->Reset() inside a named macro!
TFile::Open() is a static function; you should not call it on an object (…->Open()) but simply call TFile::Open() and use the returned TFile*, which you delete in the end, e.g.
TFile* myFile = TFile::Open("myFile.root");
...
delete myFile;
No need to call TFile::Close() etc. So I’d use:
void runSpectrumBAM(){
int iM,iR;
int nR = 500;
char material[30];
char folder[1000];
char suffix[400];
char fluence[1000];
TH1F *h_Ptmp;
TH1F *h_Stmp;
// NO! gROOT->Reset();
sprintf(folder,"/media/FREECOM\ HDD/DATA/Emax8MeV/WithoutPSF");
//Loop over material
for(iM=0; iM<2; iM++){
//Loop over runs
for(iR=0 ; iR<nR ; iR++){
if(iM==0){
sprintf(material,"Water");
sprintf(suffix,"%u%03d",1,iR);
}
else{
sprintf(material,"EFD_10cm");
sprintf(suffix,"%u%03d",2,iR);
}
//print file-name
sprintf(fluence,"%s/plots/spectra/histos/histos_Spectrum_%s_xCoord_0cm_yCoord_0cm_depth_10.05cm_%s.root",
folder,material,suffix);
TFile* fluenceFile = TFile::Open(fluence,"read");
cout<<"* Loading fluence file: "<<fluence<<endl;
//Copy histograms of interest depending on input parameter (either electron or photon)
h_Ptmp = new TH1F(*h_primaryElectronFluenceSpectrum);
h_Stmp = new TH1F(*h_scatterElectronFluenceSpectrum);
delete fluenceFile;
}//iR
}//iM
}//end
Thanks for your help, but unfortunately it still crashes. I used the code you gave me and it crashed at the second file with the message cited below. Removing the delete-statement makes the program run exactly the same way it did before, crashing after 994 files.
