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Different results for same information extracted in different ways [message #17464] 
Fri, 07 November 2014 13:42 
Mamen
Messages: 55 Registered: January 2009 Location: Mainz

continuous participant 
From: *unitymedia.net


Hi guys,
I'm having a problem since yesterday with the way I extract de same information from a histogram. Doing it in different ways I get different results, but I don't understand why or what am I doing wrong. Maybe somebody can help me.
I'll try to explain my problem in the best way I can.
I have a root file, let's call it Input.root, with a structure with two ntuples:
truthTuple:
 eppx // ep: positive electron, px: component x of momentum
 empx // em: negative electron, px: component x of momentum
 eppy // ep: positive electron, py: component y of momentum
 empy // em: negative electron, py: component y of momentum
 eppz// ep: positive electron, pz: component z of momentum
 empz // em: negative electron, pz: component z of momentum
 and others, but let's keep only these for the example
recoTuple:
 eppid // Particle Identification for positron hypothesis 0: Charged, 1:Very loose, 2: Loose, 3: Tight, 4: Very Thight
 empid // Particle Identification for electron hypothesis 0: Charged, 1:Very loose, 2: Loose, 3: Tight, 4: Very Thight
 feppx // ep: positive electron, px: component x of momentum
 fempx // em: negative electron, px: component x of momentum
 feppy // ep: positive electron, py: component y of momentum
 fempy // em: negative electron, py: component y of momentum
 feppz// ep: positive electron, pz: component z of momentum
 fempz // em: negative electron, pz: component z of momentum
 and others, but let's keep only these for the example
Ok, So I define two histograms
True = new TH1D ("True", "True", Nbins, Bin_min, Bin_max);
Reco = new TH1D ("Reco", "Reco", Nbins, Bin_min, Bin_max);
And after opening the root file I do:
TFile *t=new TFile("Input.root");
TTree *truthTuple = (TTree*)t>Get("truthTuple");
TTree *recoTuple = (TTree*)t>Get("recoTuple");
// Projection of Real Statistics Files/* IT HAS TO BE DONE WITH THE REAL STATISTICS FILE*/
truthTuple>Project("True", "variable", "eppid>3");
recoTuple>Project("Reco", "(sqrt((feppe+fempe)**2(feppx+fempx)**2(feppy+fempy)**2(feppz+fempz)**2))**2", "eppid>3");
After this, if I do
Reco>GetEntries();
I get 2323 entries
if I do:
int TotalEntries=0;
for (int i=0; i <Nbins;i++ )
{
TotalEntries=TotalEntries+Reco>GetBinContent(i+1);// histograms start on bin=1 not bin=0
}
cout << "Total Reco Entries: "<< TotalEntries<< endl;
I get "Total Reco Entries: 2297", when I think the result should be the same than Reco>GetEntries();
Does anybody have an idea of what can I be doing wrong?
On the other hand, if I fill the histogram differently, i.e. setting branch addresses and filling after applying a cut,
I also get a different number of entries in the histogram.
That would be something like that:
// Variables to be read and filled recoTuple
float feppx;
float feppy;
float feppz;
float feppe;
float fepp3;
float fepcosth;
int eppid, ntrk;
recoTuple>SetBranchAddress("feppx", &feppx);
recoTuple>SetBranchAddress("feppy", &feppy);
recoTuple>SetBranchAddress("feppz", &feppz);
recoTuple>SetBranchAddress("feppe", &feppe);
recoTuple>SetBranchAddress("fepp3", &fepp3);
recoTuple>SetBranchAddress("epcosth", &fepcosth);
recoTuple>SetBranchAddress("eppid", &eppid);
recoTuple>SetBranchAddress("ntrk", &ntrk);
float fempx;
float fempy;
float fempz;
float fempe;
float femp3;
float femcosth;
int empid;
recoTuple>SetBranchAddress("fempx", &fempx);
recoTuple>SetBranchAddress("fempy", &fempy);
recoTuple>SetBranchAddress("fempz", &fempz);
recoTuple>SetBranchAddress("fempe", &fempe);
recoTuple>SetBranchAddress("femp3", &femp3);
recoTuple>SetBranchAddress("emcosth", &femcosth);
recoTuple>SetBranchAddress("empid", &empid);
float fpi0px;
float fpi0py;
float fpi0pz;
float fpi0pe;
recoTuple>SetBranchAddress("fpi0px", &fpi0px);
recoTuple>SetBranchAddress("fpi0py", &fpi0py);
recoTuple>SetBranchAddress("fpi0pz", &fpi0pz);
recoTuple>SetBranchAddress("fpi0pe", &fpi0pe);
TH1D * RecoFill;
RecoFill = new TH1D("RecoFill", "RecoFill", Nbins, Bin_max, Bin_max);
long NEntriesReco=(long)recoTuple>GetEntries();
int kkk=0;
for (int k=0; k<NEntriesReco; k++)
{
recoTuple>GetEntry(k);
if( eppid>3)
{
if (kkk % 10000 == 0 && kkk != 0)
{
cout<<"*** FILLING *** "<< kkk << " : " <<endl;
}
kkk++;
RecoFill>Fill((sqrt((feppe+fempe)**2(feppx+fempx)**2(feppy+fempy)**2(feppz+fempz)**2))**2);
}
}
cout<< "RecoFill: "<< RecoFill>GetEntries()<<endl;
In this case I get that the number of Entries is 2239, again a number different from the two previous ones.
I am representing always the same variable, and I am applying always the same cuts in different ways.
Does somebody know what am i doing wrong?
I've tried doing it with two different macros and also at the same time inside a unique macro. Always I get the discrepancies. I have also tested the cuts, the variables, tried different ones, the number of bins, and bin limits in the histograms... I am now puzzled, and I really don't know how to continue...
Thank you very much in advance.
Cheers,
Mamen



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