// Example of analysis class for the H1 data. // ========================================= // // This file uses 4 large data sets from the H1 collaboration at DESY Hamburg. // One can access these data sets (277 MBytes) from the standard Root web site // at: ftp://root.cern.ch/root/h1analysis/ // The Physics plots below generated by this example cannot be produced when // using smaller data sets. // // There are several ways to analyze data stored in a Root Tree // -Using TTree::Draw: This is very convenient and efficient for small tasks. // A TTree::Draw call produces one histogram at the time. The histogram // is automatically generated. The selection expression may be specified // in the command line. // // -Using the TTreeViewer: This is a graphical interface to TTree::Draw // with the same functionality. // // -Using the code generated by TTree::MakeClass: In this case, the user // creates an instance of the analysis class. He has the control over // the event loop and he can generate an unlimited number of histograms. // // -Using the code generated by TTree::MakeSelector. Like for the code // generated by TTree::MakeClass, the user can do complex analysis. // However, he cannot control the event loop. The event loop is controlled // by TTree::Process called by the user. This solution is illustrated // by the current code. The advantage of this method is that it can be run // in a parallel environment using PROOF (the Parallel Root Facility). // // A chain of 4 files (originally converted from PAW ntuples) is used // to illustrate the various ways to loop on Root data sets. // Each data set contains a Root Tree named "h42" // The class definition in h1analysis.h has been generated automatically // by the Root utility TTree::MakeSelector using one of the files with the // following statement: // h42->MakeSelector("h1analysis"); // This produces two files: h1analysis.h and h1analysis.C (skeleton of this file) // The h1analysis class is derived from the Root class TSelector. // // The following members functions are called by the TTree::Process functions. // Begin(): called everytime a loop on the tree starts. // a convenient place to create your histograms. // SlaveBegin(): // // Notify(): This function is called at the first entry of a new Tree // in a chain. // Process(): called to analyze each entry. // // SlaveTerminate(): // // Terminate(): called at the end of a loop on a TTree. // a convenient place to draw/fit your histograms. // // To use this file, try the following session // // Root > gROOT->Time(); //will show RT & CPU time per command // //==> A- create a TChain with the 4 H1 data files // The chain can be created by executed the short macro h1chain.C below: // { // TChain chain("h42"); // chain.Add("$H1/dstarmb.root"); // 21330730 bytes 21920 events // chain.Add("$H1/dstarp1a.root"); // 71464503 bytes 73243 events // chain.Add("$H1/dstarp1b.root"); // 83827959 bytes 85597 events // chain.Add("$H1/dstarp2.root"); // 100675234 bytes 103053 events // //where $H1 is a system symbol pointing to the H1 data directory. // } // // Root > .x h1chain.C // //==> B- loop on all events // Root > chain.Process("h1analysis.C") // //==> C- same as B, but in addition fill the entry list with selected entries. // The entry list is saved to a file "elist.root" by the Terminate function. // To see the list of selected events, you can do elist->Print("all"). // The selection function has selected 7525 events out of the 283813 events // in the chain of files. (2.65 per cent) // Root > chain.Process("h1analysis.C","fillList") // //==> D- Process only entries in the entry list // The entry list is read from the file in elist.root generated by step C // Root > chain.Process("h1analysis.C","useList") // //==> E- the above steps have been executed via the interpreter. // You can repeat the steps B, C and D using the script compiler // by replacing "h1analysis.C" by "h1analysis.C+" or "h1analysis.C++" // // in a new session with ,eg: // //==> F- Create the chain as in A, then execute // Root > chain.Process("h1analysis.C+","useList") // // The commands executed with the 4 different methods B,C,D and E // produce two canvases shown below: // begin_html the Dstar plot end_html // begin_html the Tau D0 plot end_html // // The same analysis can be run on PROOF. For a quick try start a PROOF-Lite // session // // Root > TProof *p = TProof::Open("") // // create (if mot already done) the chain by executing the 'h1chain.C' macro // mentioned above, and then tell ROOT to use PROOF to process the chain: // // Root > chain.SetProof() // // You can then repeat step B above. Step C can also be executed in PROOF. However, // step D cannot be executed in PROOF as in the local session (i.e. just passing // option 'useList'): to use the entry list you have to // //==> G- Load first in the session the list form the file // // Root > TFile f("elist.root") // Root > TEntryList *elist = (TEntryList *) f.Get("elist") // // set it on the chain: // // Root > chain.SetEntryList(elist) // // call Process as in step B. Of course this works also for local processing. // //Author: Rene Brun #include "h1analysis.h" #include "TH2.h" #include "TF1.h" #include "TStyle.h" #include "TCanvas.h" #include "TPaveStats.h" #include "TLine.h" #include "TMath.h" const Double_t dxbin = (0.17-0.13)/40; // Bin-width const Double_t sigma = 0.0012; //_____________________________________________________________________ Double_t fdm5(Double_t *xx, Double_t *par) { Double_t x = xx[0]; if (x <= 0.13957) return 0; Double_t xp3 = (x-par[3])*(x-par[3]); Double_t res = dxbin*(par[0]*TMath::Power(x-0.13957, par[1]) + par[2] / 2.5066/par[4]*TMath::Exp(-xp3/2/par[4]/par[4])); return res; } //_____________________________________________________________________ Double_t fdm2(Double_t *xx, Double_t *par) { Double_t x = xx[0]; if (x <= 0.13957) return 0; Double_t xp3 = (x-0.1454)*(x-0.1454); Double_t res = dxbin*(par[0]*TMath::Power(x-0.13957, 0.25) + par[1] / 2.5066/sigma*TMath::Exp(-xp3/2/sigma/sigma)); return res; } //_____________________________________________________________________ void h1analysis::Begin(TTree * /*tree*/) { // function called before starting the event loop // -it performs some cleanup // -it creates histograms // -it sets some initialisation for the entry list // This is needed when re-processing the object Reset(); //print the option specified in the Process function. TString option = GetOption(); Info("Begin", "starting h1analysis with process option: %s", option.Data()); //process cases with entry list if (fChain) fChain->SetEntryList(0); delete gDirectory->GetList()->FindObject("elist"); // case when one creates/fills the entry list if (option.Contains("fillList")) { fillList = kTRUE; elist = new TEntryList("elist", "H1 selection from Cut"); // Add to the input list for processing in PROOF, if needed if (fInput) { fInput->Add(new TNamed("fillList","")); // We send a clone to avoid double deletes when importing the result fInput->Add(elist); // This is needed to avoid warnings from output-to-members mapping elist = 0; } } if (fillList) Info("Begin", "creating an entry-list"); // case when one uses the entry list generated in a previous call if (option.Contains("useList")) { useList = kTRUE; if (fInput) { // Option "useList" not supported in PROOF directly Warning("Begin", "option 'useList' not supported in PROOF - ignoring"); Warning("Begin", "the entry list must be set on the chain *before* calling Process"); } else { TFile f("elist.root"); elist = (TEntryList*)f.Get("elist"); if (elist) elist->SetDirectory(0); //otherwise the file destructor will delete elist } } } //_____________________________________________________________________ void h1analysis::SlaveBegin(TTree *tree) { // function called before starting the event loop // -it performs some cleanup // -it creates histograms // -it sets some initialisation for the entry list //initialize the Tree branch addresses Init(tree); //print the option specified in the Process function. TString option = GetOption(); Info("SlaveBegin", "starting h1analysis with process option: %s (tree: %p)", option.Data(), tree); //create histograms hdmd = new TH1F("hdmd","dm_d",40,0.13,0.17); h2 = new TH2F("h2","ptD0 vs dm_d",30,0.135,0.165,30,-3,6); fOutput->Add(hdmd); fOutput->Add(h2); // Entry list stuff (re-parse option because on PROOF only SlaveBegin is called) if (option.Contains("fillList")) { fillList = kTRUE; // Get the list if (fInput) { if ((elist = (TEntryList *) fInput->FindObject("elist"))) // Need to clone to avoid problems when destroying the selector elist = (TEntryList *) elist->Clone(); if (elist) fOutput->Add(elist); else fillList = kFALSE; } } if (fillList) Info("SlaveBegin", "creating an entry-list"); } //_____________________________________________________________________ Bool_t h1analysis::Process(Long64_t entry) { // entry is the entry number in the current Tree // Selection function to select D* and D0. fProcessed++; //in case one entry list is given in input, the selection has already been done. if (!useList) { // Read only the necessary branches to select entries. // return as soon as a bad entry is detected // to read complete event, call fChain->GetTree()->GetEntry(entry) b_md0_d->GetEntry(entry); if (TMath::Abs(md0_d-1.8646) >= 0.04) return kFALSE; b_ptds_d->GetEntry(entry); if (ptds_d <= 2.5) return kFALSE; b_etads_d->GetEntry(entry); if (TMath::Abs(etads_d) >= 1.5) return kFALSE; b_ik->GetEntry(entry); ik--; //original ik used f77 convention starting at 1 b_ipi->GetEntry(entry); ipi--; b_ntracks->GetEntry(entry); b_nhitrp->GetEntry(entry); if (nhitrp[ik]*nhitrp[ipi] <= 1) return kFALSE; b_rend->GetEntry(entry); b_rstart->GetEntry(entry); if (rend[ik] -rstart[ik] <= 22) return kFALSE; if (rend[ipi]-rstart[ipi] <= 22) return kFALSE; b_nlhk->GetEntry(entry); if (nlhk[ik] <= 0.1) return kFALSE; b_nlhpi->GetEntry(entry); if (nlhpi[ipi] <= 0.1) return kFALSE; b_ipis->GetEntry(entry); ipis--; if (nlhpi[ipis] <= 0.1) return kFALSE; b_njets->GetEntry(entry); if (njets < 1) return kFALSE; } // if option fillList, fill the entry list if (fillList) elist->Enter(entry); // to read complete event, call fChain->GetTree()->GetEntry(entry) // read branches not processed in ProcessCut b_dm_d->GetEntry(entry); //read branch holding dm_d b_rpd0_t->GetEntry(entry); //read branch holding rpd0_t b_ptd0_d->GetEntry(entry); //read branch holding ptd0_d //fill some histograms hdmd->Fill(dm_d); h2->Fill(dm_d,rpd0_t/0.029979*1.8646/ptd0_d); // Count the number of selected events fStatus++; return kTRUE; } //_____________________________________________________________________ void h1analysis::SlaveTerminate() { // nothing to be done if (fillList) Info("SlaveTerminate", "elist created with %lld entries", elist->GetN()); } //_____________________________________________________________________ void h1analysis::Terminate() { // function called at the end of the event loop hdmd = dynamic_cast(fOutput->FindObject("hdmd")); h2 = dynamic_cast(fOutput->FindObject("h2")); if (hdmd == 0 || h2 == 0) { Error("Terminate", "hdmd = %p , h2 = %p", hdmd, h2); return; } //create the canvas for the h1analysis fit gStyle->SetOptFit(); TCanvas *c1 = new TCanvas("c1","h1analysis analysis",10,10,800,600); c1->SetBottomMargin(0.15); hdmd->GetXaxis()->SetTitle("m_{K#pi#pi} - m_{K#pi}[GeV/c^{2}]"); hdmd->GetXaxis()->SetTitleOffset(1.4); //fit histogram hdmd with function f5 using the loglikelihood option if (gROOT->GetListOfFunctions()->FindObject("f5")) delete gROOT->GetFunction("f5"); TF1 *f5 = new TF1("f5",fdm5,0.139,0.17,5); f5->SetParameters(1000000, .25, 2000, .1454, .001); hdmd->Fit("f5","lr"); //create the canvas for tau d0 gStyle->SetOptFit(0); gStyle->SetOptStat(1100); TCanvas *c2 = new TCanvas("c2","tauD0",100,100,800,600); c2->SetGrid(); c2->SetBottomMargin(0.15); // Project slices of 2-d histogram h2 along X , then fit each slice // with function f2 and make a histogram for each fit parameter // Note that the generated histograms are added to the list of objects // in the current directory. if (gROOT->GetListOfFunctions()->FindObject("f2")) delete gROOT->GetFunction("f2"); TF1 *f2 = new TF1("f2",fdm2,0.139,0.17,2); f2->SetParameters(10000, 10); h2->FitSlicesX(f2,0,-1,1,"qln"); TH1D *h2_1 = (TH1D*)gDirectory->Get("h2_1"); h2_1->GetXaxis()->SetTitle("#tau[ps]"); h2_1->SetMarkerStyle(21); h2_1->Draw(); c2->Update(); TLine *line = new TLine(0,0,0,c2->GetUymax()); line->Draw(); // Have the number of entries on the first histogram (to cross check when running // with entry lists) TPaveStats *psdmd = (TPaveStats *)hdmd->GetListOfFunctions()->FindObject("stats"); psdmd->SetOptStat(1110); c1->Modified(); //save the entry list to a Root file if one was produced if (fillList) { if (!elist) elist = dynamic_cast(fOutput->FindObject("elist")); if (elist) { Printf("Entry list 'elist' created:"); elist->Print(); TFile efile("elist.root","recreate"); elist->Write(); } else { Error("Terminate", "entry list requested but not found in output"); } } // Notify the amount of processed events if (!fInput) Info("Terminate", "processed %lld events", fProcessed); }