// @(#)root/test:$Id$ // Author: Rene Brun 19/01/97 //////////////////////////////////////////////////////////////////////// // // A simple example with a ROOT tree // ================================= // // This program creates : // - a ROOT file // - a tree // Additional arguments can be passed to the program to control the flow // of execution. (see comments describing the arguments in the code). // Event nevent comp split fill // All arguments are optional. Default is: // Event 400 1 1 1 // // In this example, the tree consists of one single "super branch" // The statement ***tree->Branch("event", &event, 64000,split);*** below // will parse the structure described in Event.h and will make // a new branch for each data member of the class if split is set to 1. // - 9 branches corresponding to the basic types fType, fNtrack,fNseg, // fNvertex,fFlag,fTemperature,fMeasures,fMatrix,fClosesDistance. // - 3 branches corresponding to the members of the subobject EventHeader. // - one branch for each data member of the class Track of TClonesArray. // - one branch for the TRefArray of high Pt tracks // - one branch for the TRefArray of muon tracks // - one branch for the reference pointer to the last track // - one branch for the object fH (histogram of class TH1F). // // if split = 0 only one single branch is created and the complete event // is serialized in one single buffer. // if split = -2 the event is split using the old TBranchObject mechanism // if split = -1 the event is streamed using the old TBranchObject mechanism // if split > 0 the event is split using the new TBranchElement mechanism. // // if comp = 0 no compression at all. // if comp = 1 event is compressed. // if comp = 2 same as 1. In addition branches with floats in the TClonesArray // are also compressed. // The 4th argument fill can be set to 0 if one wants to time // the percentage of time spent in creating the event structure and // not write the event in the file. // In this example, one loops over nevent events. // The branch "event" is created at the first event. // The branch address is set for all other events. // For each event, the event header is filled and ntrack tracks // are generated and added to the TClonesArray list. // For each event the event histogram is saved as well as the list // of all tracks. // // The two TRefArray contain only references to the original tracks owned by // the TClonesArray fTracks. // // The number of events can be given as the first argument to the program. // By default 400 events are generated. // The compression option can be activated/deactivated via the second argument. // // ---Running/Linking instructions---- // This program consists of the following files and procedures. // - Event.h event class description // - Event.C event class implementation // - MainEvent.C the main program to demo this class might be used (this file) // - EventCint.C the CINT dictionary for the event and Track classes // this file is automatically generated by rootcint (see Makefile), // when the class definition in Event.h is modified. // // ---Analyzing the Event.root file with the interactive root // example of a simple session // Root > TFile f("Event.root") // Root > T.Draw("fNtrack") //histogram the number of tracks per event // Root > T.Draw("fPx") //histogram fPx for all tracks in all events // Root > T.Draw("fXfirst:fYfirst","fNtrack>600") // //scatter-plot for x versus y of first point of each track // Root > T.Draw("fH.GetRMS()") //histogram of the RMS of the event histogram // // Look also in the same directory at the following macros: // - eventa.C an example how to read the tree // - eventb.C how to read events conditionally // //////////////////////////////////////////////////////////////////////// #include #include "Riostream.h" #include "TROOT.h" #include "TFile.h" #include "TNetFile.h" #include "TRandom.h" #include "TTree.h" #include "TBranch.h" #include "TClonesArray.h" #include "TStopwatch.h" #include "Event.h" using namespace std; //______________________________________________________________________________ int main(int argc, char **argv) { Int_t nevent = 400; // by default create 400 events Int_t comp = 1; // by default file is compressed Int_t split = 1; // by default, split Event in sub branches Int_t write = 1; // by default the tree is filled Int_t hfill = 0; // by default histograms are not filled Int_t read = 0; Int_t arg4 = 1; Int_t arg5 = 600; //default number of tracks per event Int_t netf = 0; Int_t punzip = 0; if (argc > 1) nevent = atoi(argv[1]); if (argc > 2) comp = atoi(argv[2]); if (argc > 3) split = atoi(argv[3]); if (argc > 4) arg4 = atoi(argv[4]); if (argc > 5) arg5 = atoi(argv[5]); if (arg4 == 0) { write = 0; hfill = 0; read = 1;} if (arg4 == 1) { write = 1; hfill = 0;} if (arg4 == 2) { write = 0; hfill = 0;} if (arg4 == 10) { write = 0; hfill = 1;} if (arg4 == 11) { write = 1; hfill = 1;} if (arg4 == 20) { write = 0; read = 1;} //read sequential if (arg4 == 21) { write = 0; read = 1; punzip = 1;} //read sequential + parallel unzipping if (arg4 == 25) { write = 0; read = 2;} //read random if (arg4 >= 30) { netf = 1; } //use TNetFile if (arg4 == 30) { write = 0; read = 1;} //netfile + read sequential if (arg4 == 35) { write = 0; read = 2;} //netfile + read random if (arg4 == 36) { write = 1; } //netfile + write sequential Int_t branchStyle = 1; //new style by default if (split < 0) {branchStyle = 0; split = -1-split;} TFile *hfile; TTree *tree; Event *event = 0; // Fill event, header and tracks with some random numbers // Create a timer object to benchmark this loop TStopwatch timer; timer.Start(); Long64_t nb = 0; Int_t ev; Int_t bufsize; Double_t told = 0; Double_t tnew = 0; Int_t printev = 100; if (arg5 < 100) printev = 1000; if (arg5 < 10) printev = 10000; // Read case if (read) { if (netf) { hfile = new TNetFile("root://localhost/root/test/EventNet.root"); } else hfile = new TFile("Event.root"); tree = (TTree*)hfile->Get("T"); TBranch *branch = tree->GetBranch("event"); branch->SetAddress(&event); Int_t nentries = (Int_t)tree->GetEntries(); nevent = TMath::Min(nevent,nentries); if (read == 1) { //read sequential //by setting the read cache to -1 we set it to the AutoFlush value when writing Int_t cachesize = -1; if (punzip) tree->SetParallelUnzip(); tree->SetCacheSize(cachesize); tree->SetCacheLearnEntries(1); //one entry is sufficient to learn tree->SetCacheEntryRange(0,nevent); for (ev = 0; ev < nevent; ev++) { tree->LoadTree(ev); //this call is required when using the cache if (ev%printev == 0) { tnew = timer.RealTime(); printf("event:%d, rtime=%f s\n",ev,tnew-told); told=tnew; timer.Continue(); } nb += tree->GetEntry(ev); //read complete event in memory } } else { //read random Int_t evrandom; for (ev = 0; ev < nevent; ev++) { if (ev%printev == 0) std::cout<<"event="<Rndm(1)); nb += tree->GetEntry(evrandom); //read complete event in memory } } } else { // Write case // Create a new ROOT binary machine independent file. // Note that this file may contain any kind of ROOT objects, histograms, // pictures, graphics objects, detector geometries, tracks, events, etc.. // This file is now becoming the current directory. if (netf) { hfile = new TNetFile("root://localhost/root/test/EventNet.root","RECREATE","TTree benchmark ROOT file"); } else hfile = new TFile("Event.root","RECREATE","TTree benchmark ROOT file"); hfile->SetCompressionLevel(comp); // Create histogram to show write_time in function of time Float_t curtime = -0.5; Int_t ntime = nevent/printev; TH1F *htime = new TH1F("htime","Real-Time to write versus time",ntime,0,ntime); HistogramManager *hm = 0; if (hfill) { TDirectory *hdir = new TDirectory("histograms", "all histograms"); hm = new HistogramManager(hdir); } // Create a ROOT Tree and one superbranch tree = new TTree("T","An example of a ROOT tree"); tree->SetAutoSave(1000000000); // autosave when 1 Gbyte written tree->SetCacheSize(10000000); // set a 10 MBytes cache (useless when writing local files) bufsize = 64000; if (split) bufsize /= 4; event = new Event(); // By setting the value, we own the pointer and must delete it. TTree::SetBranchStyle(branchStyle); TBranch *branch = tree->Branch("event", &event, bufsize,split); branch->SetAutoDelete(kFALSE); if(split >= 0 && branchStyle) tree->BranchRef(); Float_t ptmin = 1; for (ev = 0; ev < nevent; ev++) { if (ev%printev == 0) { tnew = timer.RealTime(); printf("event:%d, rtime=%f s\n",ev,tnew-told); htime->Fill(curtime,tnew-told); curtime += 1; told=tnew; timer.Continue(); } event->Build(ev, arg5, ptmin); if (write) nb += tree->Fill(); //fill the tree if (hm) hm->Hfill(event); //fill histograms } if (write) { hfile = tree->GetCurrentFile(); //just in case we switched to a new file hfile->Write(); tree->Print(); } } // We own the event (since we set the branch address explicitly), we need to delete it. delete event; event = 0; // Stop timer and print results timer.Stop(); Float_t mbytes = 0.000001*nb; Double_t rtime = timer.RealTime(); Double_t ctime = timer.CpuTime(); printf("\n%d events and %lld bytes processed.\n",nevent,nb); printf("RealTime=%f seconds, CpuTime=%f seconds\n",rtime,ctime); if (read) { tree->PrintCacheStats(); printf("You read %f Mbytes/Realtime seconds\n",mbytes/rtime); printf("You read %f Mbytes/Cputime seconds\n",mbytes/ctime); } else { printf("compression level=%d, split=%d, arg4=%d\n",comp,split,arg4); printf("You write %f Mbytes/Realtime seconds\n",mbytes/rtime); printf("You write %f Mbytes/Cputime seconds\n",mbytes/ctime); //printf("file compression factor = %f\n",hfile.GetCompressionFactor()); } hfile->Close(); return 0; }