I am using the skeleton produced by TTree::MakeSelector to analyse some MC from the kk generator. When I look at a certain branch from a tree using both this (with no cuts added) and also by looking at it directly using TBrowser (also with no cuts) I get totally different histograms. The Selector method shows one sharp spike, whereas the TBRowser shows the correct broad distribution (I have seen many examples of the plot being a broad distribution rather than one spike). Here is the code I used in the skeleton: #define mark2_cxx #include "mark2.h" #include "TH2.h" #include "TStyle.h" #include "TCanvas.h" void mark2::Begin(TTree *tree) { Init(tree); TString option = GetOption(); gDirectory->Delete("qsquared"); qsquared = new TH1F("qsquared", "q squared, tau", 120, 0, 6); } Bool_t mark2::ProcessCut(Int_t entry) { return kTRUE; } void mark2::ProcessFill(Int_t entry) { b_had_mass->GetEntry(23); qsquared->Fill(had_mass); } void mark2::Terminate() { gStyle->SetOptStat(11111); TCanvas *c1 = new TCanvas("c1", "kk2 comparison with koralb", 10, 10, 800, 600); c1->SetBottomMargin(0.15); qsquared->GetXaxis()->SetTitle("Invariant Mass of tau"); qsquared->GetXaxis()->SetTitleOffset(1.4); qsquared->Draw(); } The above code is called mark2.C. In root I then do: .x chain.C where chain.C contains: { TChain chain("h5"); chain.Add("kk.root"); } Finally I run the mark2.C with chain.Process("mark2.C") and get the histogram drawn. I also thought I should be able to do: TFile kk("kk.root") h5.Process("mark2.C") where h5 is a TNuple, but this crashes. Is there a way to do this since a chain seems unnecessary if you only have one root file you want to use. I hope someone can spot my mistake. Thanks, Mark. -- -------------------------------------------------------------------------------------------- Mark Hodgkinson phone (+44)(0)161 2754150 Office 7-11 email markhod@hep.man.ac.uk HEP Group Schuster Laboratory University of Manchester Oxford Road Manchester England http://www.hep.man.ac.uk/~markhod
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