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Re: Different results for same information extracted in different ways [message #17466 is a reply to message #17465] Fri, 07 November 2014 14:59 Go to previous messageGo to previous message
Mamen is currently offline  Mamen
Messages: 55
Registered: January 2009
Location: Mainz
continuous participant
From: *unity-media.net
Thanks a lot Klaus,

Looping over Nbins+2 in the histogram created using "->Project();" helps me getting the same number of events than using ->GetEntries();

However I still need to understand why I don't get the same number of entries looping over the tree or doing a Project.
I checked out the values that were being filled in the tree like that:

if (kk % 10000 == 0 && kk != 0) 
	      	    {      	
	      	      cout<<"*** FILLING *** "<< kk << " : "<< cosThetaP << "\t"<< Pz << " / " <<(sqrt(pow(Px, 2)+pow(Py,2)+pow(Pz,2)))<< endl;
	      	    }

kk++;


(cosThetaP, Pz, Px and Py are defined from the branch addressed variables, and cosThetaP is the variable I want at the end fill in the Histogram)
and I saw that costThetaP, as well as Pz and sqrt(...) were showing sometimes "-nan" value.

So I added a variable that counted how many times I was getting nan:


		  if (isnan(cosThetaP))
                {
                   fail++;
                    //cout << "cosThe is nan"<<endl;
                }


However, the number of entries still don't match.

In addition I have also got the number of entries from the histogram filled looping over the Tree, summing up over Nbins, summing up over Nbins+2 and using GetEntries(), and the results are very strange.

For different files I get:

File Reco->GetEntries()  Sum=Sum+Reco->GetBinContent(i)  Sum=Sum+Reco->GetBinContent(i)    Nr. -nan events    
                           from bin=1 to bin=Nbins          from bin=0 to bin=Nbins+1        value of fail
===========================================================================================================
1        493075                 564152                          487270                          21476
2        379395                 510432                          465690                          14101
3        646731                 373536                               0                          11467
4        505865                 380024                               0                          22111
===========================================================================================================




Before filling the histogram looping over the tree I've initialized them using

for (int b=0; b<Nbins+2; b++)
	    {
	      Eff->SetBinContent(b, 0);
	      Eff->SetBinError(b, 0);
	      
	      Reco->SetBinContent(b, 0);
	      Reco->SetBinError(b, 0);
	    }


Can the over/underflow bins have negative values??? even after initializing them to 0 values???

 
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