SAA3 as built.
[u/mrichter/AliRoot.git] / STEER / ReadESDfriend.C
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6bc5f287 1//********************************************************************
2// Example of accessing the information stored in ESD friends
3// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
4//********************************************************************
5
6#if !defined( __CINT__) || defined(__MAKECINT__)
7 #include <Riostream.h>
8 #include <TFile.h>
500d54ab 9 #include <TChain.h>
6bc5f287 10
11 #include "AliESD.h"
12 #include "AliESDfriend.h"
500d54ab 13 #include "AliTrackPointArray.h"
6bc5f287 14#endif
15
16void ReadESDfriend(Bool_t readFriend=kTRUE) {
500d54ab 17 Char_t *name[]={
18 //Put here the names of the ESD files to be chained
19 "AliESDs.root"
20 };
21 Int_t n=sizeof(name)/sizeof(Char_t *);
22 TChain *esdTree=new TChain("esdTree");
23 for (Int_t i=0; i<n; i++) esdTree->AddFile(name[i]);
24
6bc5f287 25 AliESD *ev=0;
26 esdTree->SetBranchAddress("ESD",&ev);
27
500d54ab 28 // Attach the branch with ESD friends
6bc5f287 29 AliESDfriend *evf=0;
30 if (readFriend) {
500d54ab 31 esdTree->SetBranchStatus("ESDfriend*",1);
32 esdTree->SetBranchAddress("ESDfriend.",&evf);
6bc5f287 33 }
34
35 Int_t nev=esdTree->GetEntries();
36 for (Int_t i=0; i<nev; i++) {
6bc5f287 37 esdTree->GetEntry(i);
38
500d54ab 39 cout<<endl<<"Event number: "<<i<<endl;
40 Int_t n=ev->GetNumberOfTracks();
41 cout<<"Number of tracks: "<<n<<endl;
42 if (n==0) continue;
43
6bc5f287 44 ev->SetESDfriend(evf); //Attach the friend to the ESD
45
46 // Now the attached information can be accessed via pointer to ESD.
47 // Example: indices of the TPC clusters associated with the track number 0.
48 const AliESDtrack *t=ev->GetTrack(0);
500d54ab 49 Int_t idx[AliESDfriendTrack::kMaxTPCcluster];
50 n=t->GetTPCclusters(idx);
51 cout<<"Track number 0"<<endl;
52 cout<<" Number of TPC clusters: "<<n<<endl;
53 cout<<" Index of the 7th TPC cluster: "<<idx[7]<<endl;
54
55 // Example: track points associated with the track number 0.
56 const AliTrackPointArray *pa=t->GetTrackPointArray();
57 if (pa==0) continue;
58 n=pa->GetNPoints();
59 const Float_t *x=pa->GetX();
60 cout<<" Number of track points: "<<n<<endl;
61 if (n>7)
62 cout<<" X coordinate of the 7th track point: "<<x[7]<<endl;
63
6bc5f287 64 }
65
66 delete esdTree;
67}