[u/mrichter/AliRoot.git] / ANALYSIS / testEvent.C

// #####    TO RUN THIS MACRO:
// bash$ aliroot         (due to AliInfo, AliError, ...)
// root[0] gSystem->Load("libANALYSIS_NEW");
// IN case you do not have the include path set to AliRoot includes:
// root[1] gSystem->AddIncludePath("-I\"$ALICE_ROOT/include\"");
// root[2] .L testEvent.C+;
// root[3] generate();
// root[4] filter_reco();

#include "TClonesArray.h"
#include "TChain.h"
#include "TH1.h"
#include "TCanvas.h"
#include "testEvent.h"   

//============= First step: generate events
void generate()
{
// Simple event generation
   AliAnalysisManager *mgr = new AliAnalysisManager();
   TaskGenerate *task = new TaskGenerate("gener");
   mgr->AddTask(task);

   if (mgr->InitAnalysis()) {
      mgr->PrintStatus();
      mgr->ExecAnalysis();
   }   
   delete mgr;
}   

//============= Second step: filter gammas; use TSelector functionality
void filter_reco()
{
// Filter the input events having more than 100 gammas. Reconstruct pi0's
// From gammas coming from the same vertex.
   // Get the input data as a chain
   TChain *chain = new TChain("T");
   chain->Add("event02000.root");
   chain->Add("event04000.root");
   chain->Add("event06000.root");
   chain->Add("event08000.root");
   chain->Add("event10000.root");
   // Create an analysis manager
   AliAnalysisManager *mgr = new AliAnalysisManager();
   // Create a filter task and register it
   TaskFilter *task1 = new TaskFilter("TaskFilter");
   mgr->AddTask(task1);
   // Create a reco task and register it
   TaskRecoPi0 *task2 = new TaskRecoPi0("TaskRecoPi0");
   mgr->AddTask(task2);
   // Create containers for input/output
   AliAnalysisDataContainer *cinput = mgr->CreateContainer("input0", 
                      TTree::Class(), AliAnalysisManager::kInputContainer);
   AliAnalysisDataContainer *coutput1 = mgr->CreateContainer("output0", 
                      TTree::Class(), AliAnalysisManager::kOutputContainer);
   AliAnalysisDataContainer *coutput2 = mgr->CreateContainer("output1", 
                      TList::Class(), AliAnalysisManager::kOutputContainer);
   AliAnalysisDataContainer *coutput = mgr->CreateContainer("output", 
                      TH1::Class(), AliAnalysisManager::kOutputContainer);
   // Connect containers to the task input/outputs
   mgr->ConnectInput(task1,0,cinput);
   mgr->ConnectOutput(task1,0,coutput1);
   mgr->ConnectOutput(task1,1,coutput2);
   mgr->ConnectInput(task2,0,coutput1);
   mgr->ConnectOutput(task2,0,coutput);
   // Connect input data
   cinput->SetData(chain);
   // Init analysis and start event loop
   if (mgr->InitAnalysis()) {
      mgr->PrintStatus();
      chain->Process(mgr);
   }
//   delete mgr;   
}
   
ClassImp(TaskGenerate)

//______________________________________________________________________________
void TaskGenerate::Exec(Option_t *)
{
// Generate 10k events in 5 files
   AnaEvent::CreateEvents(2000, "event02000.root");
   AnaEvent::CreateEvents(2000, "event04000.root");
   AnaEvent::CreateEvents(2000, "event06000.root");
   AnaEvent::CreateEvents(2000, "event08000.root");
   AnaEvent::CreateEvents(2000, "event10000.root");
}

ClassImp(TaskFilter)

//______________________________________________________________________________
TaskFilter::TaskFilter(const char *name) 
           :AliAnalysisTask(name,""), fEvent(0), fOutput(0), fList(0), fHist1(0), fHist2(0)
{
// Constructor
   // Input slot #0 works with a tree of events
   DefineInput(0, TTree::Class());

   // Output slot #0 writes into a tree, #1 produces a hisogram
   DefineOutput(0, TTree::Class());
   DefineOutput(1, TList::Class());
}

//______________________________________________________________________________
void TaskFilter::Init(Option_t *)
{
// Initialize branches.
   printf("   Init %s\n", GetName());
   if (!fEvent) {
      // One should first check if the branch address was taken by some other task
      char ** address = (char **)GetBranchAddress(0, "event");
      if (address) fEvent = (AnaEvent*)(*address);
      if (!fEvent) {
         fEvent = new AnaEvent();
         SetBranchAddress(0, "event", &fEvent);
      }
      // The output tree will be written to gammas.root
      TDirectory *dirsav = gDirectory;
      // Open a file for output #0
      OpenFile(0, "gammas.root", "RECREATE");
      fOutput = new TTree("TGAM", "gammas");
      TBranch *branch = fOutput->Branch("event", &fEvent, 18000,1);
      branch->SetAutoDelete(kFALSE);
      if (dirsav) dirsav->cd();
   } 
   if (!fList) {
      fList = new TList();
      fHist1 = new TH1I("ntracks", "Number of tracks per event", 100, 0, 1000);
      fHist1->SetLineColor(kRed);
      fHist2 = new TH1I("ngammas", "Number of gammas per event", 100, 0, 1000);
      fHist2->SetLineColor(kBlue);
      fList->Add(fHist1);
      fList->Add(fHist2);
   }   
}

//______________________________________________________________________________
void TaskFilter::Exec(Option_t *)
{
// Filtering.
   TTree *tinput = (TTree*)GetInputData(0);
   Long64_t ientry = tinput->GetReadEntry();
   // In this case fEvent address is already connected to the input
   if (!fEvent) return;
   // First check multiplicity
   Int_t ntracks = fEvent->GetNtracks();
   // Loop tracks and get rid of non-gammas
   AnaTrack *track;
   Int_t igamma = 0;
   for (Int_t i=0; i<ntracks; i++) {
      track = fEvent->GetTrack(i);
      if (track->GetMass() < 1.e-3) igamma++;
   }
   if (ientry%100 == 0) printf("TaskFilter -> Event %lld: %i tracks filtered %i gammas\n", ientry, ntracks, igamma);
   fHist1->Fill(ntracks);
   fHist2->Fill(igamma);
   if (igamma > 100) {
      fOutput->Fill();
      PostData(0, fOutput);
   }   
   PostData(1, fList);
}

//______________________________________________________________________________
void TaskFilter::Terminate(Option_t *)
{
// Draw some histogram at the end.
   if (!gROOT->IsBatch()) {
      fHist1->SetMaximum(2500);
      fHist1->Draw();
      fHist2->Draw("SAME");
   }   
}

ClassImp(TaskRecoPi0)

//______________________________________________________________________________
TaskRecoPi0::TaskRecoPi0(const char *name) 
           :AliAnalysisTask(name,""), fEvent(0), fGammas(0), fPions(0), fHist(0)
{
// Constructor
   // Input slot #0 works with a tree of events
   DefineInput(0, TTree::Class());

   // Output slot #1 produces a hisogram
   DefineOutput(0, TH1::Class());
}

//______________________________________________________________________________
TaskRecoPi0::~TaskRecoPi0()
{
// Dtor.
   if (fEvent) delete fEvent;
   if (fGammas) delete fGammas;
   if (fPions) delete fPions;
}   

//______________________________________________________________________________
void TaskRecoPi0::Init(Option_t *)
{
// Initialize branches.
   printf("   Init %s\n", GetName());
   if (!fEvent) {
      // One should first check if the branch address was taken by some other task
      char ** address = (char **)GetBranchAddress(0, "event");
      if (address) fEvent = (AnaEvent*)(*address);
      if (!fEvent) {
         fEvent = new AnaEvent();
         SetBranchAddress(0, "event", &fEvent);
      }
      fGammas = new TObjArray();
      fPions  = new TObjArray();
   } 
   if (!fHist) {
      fHist = new TH1F("Pt_pi0", "Pt distribution for pi0's", 100, 0., 10.);
      fHist->SetLineColor(kRed);
   }   
}

//______________________________________________________________________________
void TaskRecoPi0::Exec(Option_t *)
{
// Reconstruct Pi0's for one event
   AnaTrack *track = 0;
   Int_t ntracks = fEvent->GetNtracks();
   Int_t ngamma = 0;
   Int_t i,j;
   // Clear containers
   fGammas->Clear();
   fPions->Delete();
   fPions->Clear();
   // Loop tracks and move gammas to gamma container
   for (i=0; i<ntracks; i++) {
      track = fEvent->GetTrack(i);
      if (track->GetMass() < 1.e-3) {
         fGammas->Add(track);
         ngamma++;
      }
   }
   printf("TaskRecoPi0 -> Tracks %i \n", ntracks);

   // Loop gammas and check vertex position
   Double_t v1[3], v2[3];
   AnaTrack *tracko = 0;
   Double_t cutoff = 0.001;
   for (i=0; i<ngamma-1; i++) {
      track = (AnaTrack*)fGammas->At(i);
      v1[0] = track->GetVertex(0);
      v1[1] = track->GetVertex(1);
      v1[2] = track->GetVertex(2);
      for (j=i+1; j<ngamma; j++) {
         tracko = (AnaTrack*)fGammas->At(j);
         v2[0] = tracko->GetVertex(0);
         v2[1] = tracko->GetVertex(1);
         v2[2] = tracko->GetVertex(2);
         Double_t dist2 = (v2[0]-v1[0])*(v2[0]-v1[0])+
                          (v2[1]-v1[1])*(v2[1]-v1[1])+
                          (v2[2]-v1[2])*(v2[2]-v1[2]);
         if (dist2>cutoff*cutoff) continue;
         // We have found a pair candidate
         Double_t px = track->GetPx()+tracko->GetPx();
         Double_t py = track->GetPy()+tracko->GetPy();
         Double_t pz = track->GetPz()+tracko->GetPz();
         track = new AnaTrack(px,py,pz,0.135,0,v1[0],v1[1],v1[2]);
         fPions->Add(track);
         fHist->Fill(track->GetPt());
         break;
      }   
   }   
   PostData(0,fHist);         
}

//______________________________________________________________________________
void TaskRecoPi0::Terminate(Option_t *)
{
// Draw some histogram at the end.
   if (!gROOT->IsBatch()) {
      new TCanvas("pi0", "Pt for pi0's", 800,600);
      fHist->Draw();
   }   
}


ClassImp(AnaTrack)

//______________________________________________________________________________
AnaTrack::AnaTrack(Double_t random, Double_t *vertex) 
{
// Constructor
   Int_t itype;
   if (random<0.3) itype = 1;      // pi+
   else if (random<0.6) itype = 2; // pi-
   else if (random<0.9) itype = 3; // p
   else if (random<0.95) itype = 4; // pi0
   else itype = 5;                 // gamma
   gRandom->Rannor(fPx, fPy);
   Double_t vert_width = 0.1;
   
   switch (itype) {
      case 1:
         fMass = 0.13957 + gRandom->Gaus(0.,0.001);
         fCharge = 1;
         break;
      case 2:
         fMass = 0.13957 + gRandom->Gaus(0.,0.001);
         fCharge = -1;
         break;
      case 3:
         fMass = 0.938 + gRandom->Gaus(0.,0.002);
         fCharge = 1;
         fPx *= 0.15;
         fPy *= 0.15;
         break;
      case 4:
         fMass = 0.135 + gRandom->Gaus(0.,0.001);
         fCharge = 0;
         fPx *= 0.8;
         fPy *= 0.8;
         vert_width = 10.;
         break;
      case 5:
         fMass = 0.;
         fCharge = 0;
         fPx *= 0.5;
         fPy *= 1.5;
         break;
   };
   fPz = gRandom->Gaus(4., 2.);
   if (vertex) {
      fVertex[0] = vertex[0];
      fVertex[1] = vertex[1];
      fVertex[2] = vertex[2];
   } else {   
      fVertex[0] = gRandom->Gaus(0,vert_width);
      fVertex[1] = gRandom->Gaus(0,vert_width);
      fVertex[2] = gRandom->Gaus(0,0.01);
   }   
}

//______________________________________________________________________________
Bool_t AnaTrack::Decay(Double_t &px1, Double_t &py1, Double_t &pz1, 
                       Double_t &px2, Double_t &py2, Double_t &pz2)
{
// Decay a pi0 in 2 gammas.
   if (fCharge != 0) return kFALSE;
   if (fMass<0.132 || fMass>0.138) return kFALSE;
   Double_t phi1 = 2.*TMath::Pi()*gRandom->Rndm(); // [0,2*pi]
   Double_t phi2 = phi1 + TMath::Pi();
   if (phi2 > 2.*TMath::Pi()) phi2 -= 2.*TMath::Pi();
   Double_t r2 = gRandom->Rndm();
   Double_t theta1 = TMath::ACos(1.-2.*r2);
   Double_t p0 = GetP();
   Double_t m0 = 0.135;
   Double_t p1 = 0.5*(p0*(1-2*r2)+TMath::Sqrt(p0*p0*(1-2*r2)*(1-2*r2)+2*m0*m0));
   Double_t p2 = TMath::Sqrt(p0*p0+m0*m0-p1*p1);
   Double_t theta2 = TMath::ACos((p0-p1*(1-2*r2))/p2);
   // Px, Py and Pz in the reference frame of the pion
   px1 = p1 * TMath::Sin(theta1)*TMath::Cos(phi1);
   px2 = p2 * TMath::Sin(theta2)*TMath::Cos(phi2);
   py1 = p1 * TMath::Sin(theta1)*TMath::Sin(phi1);
   py2 = p2 * TMath::Sin(theta2)*TMath::Sin(phi2);
   pz1 = p1 * TMath::Cos(theta1);
   pz2 = p2 * TMath::Cos(theta2);
   Double_t phi = TMath::ATan2(fPy, fPx) * TMath::RadToDeg();
   Double_t theta = TMath::ACos(GetPt()/p0) * TMath::RadToDeg();
   TGeoRotation r("rot", phi+90., theta, 0.);
   Double_t loc[3], vect[3];
   p0 = TMath::Sqrt(px1*px1+py1*py1+pz1*pz1);
   loc[0] = px1/p0;
   loc[1] = py1/p0;
   loc[2] = pz1/p0;
   r.LocalToMasterVect(loc, vect);
   px1 = vect[0]*p0;
   py1 = vect[1]*p0;
   pz1 = vect[2]*p0;
//   t1 = new AnaTrack(1., fVertex);
   p0 = TMath::Sqrt(px2*px2+py2*py2+pz2*pz2);
   loc[0] = px2/p0;
   loc[1] = py2/p0;
   loc[2] = pz2/p0;
   r.LocalToMasterVect(loc, vect);
   px2 = vect[0]*p0;
   py2 = vect[1]*p0;
   pz2 = vect[2]*p0;
//   t2 = new AnaTrack(1., fVertex);
   return kTRUE;
}

//______________________________________________________________________________
ClassImp(AnaEvent)

TClonesArray *AnaEvent::fgTracks = 0;

//______________________________________________________________________________
AnaEvent::AnaEvent()
{
// Ctor
   if (!fgTracks) fgTracks = new TClonesArray("AnaTrack", 2000);
   fTracks = fgTracks;
   fEventNumber = 0;
   fNtracks = 0;
}

//______________________________________________________________________________
AnaTrack *AnaEvent::AddTrack(Double_t rnd, Double_t *vert)
{
// Add a random track
//   printf("track %d\n", fNtracks);
   TClonesArray &tracks = *fTracks;
   AnaTrack *track = new(tracks[fNtracks++]) AnaTrack(rnd, vert);
   return track;
}   

//______________________________________________________________________________
void AnaEvent::Clear(Option_t *)
{
// Clears current event.
   fTracks->Clear();
   fNtracks = 0;
   fEventNumber = 0;
}   

//______________________________________________________________________________
Int_t AnaEvent::Build(Int_t ev)
{
// Create a random event
   Clear();
   fEventNumber = ev;
   Int_t ntracks = Int_t(gRandom->Gaus(500., 100.));
   if (ntracks < 1) ntracks = 1;
   if (ntracks>1000) ntracks = 1000;
   AnaTrack *track, *track0;
   for (Int_t i=0; i<ntracks; i++) {
      Double_t rnd = gRandom->Rndm();
      if (rnd>=0.90 && rnd<0.95) {
      // Pi0 -> decay the track in 2 gammas
         track0 = new AnaTrack(rnd);
         Double_t vert[3];
         vert[0] = track0->GetVertex(0);
         vert[1] = track0->GetVertex(1);
         vert[2] = track0->GetVertex(2);
         Double_t px1,py1,pz1,px2,py2,pz2;
         if (track0->Decay(px1,py1,pz1,px2,py2,pz2)) {
            track = AddTrack(1.,vert);
            track->SetPx(px1);
            track->SetPy(py1);
            track->SetPz(pz1);
            track = AddTrack(1.,vert);
            track->SetPx(px2);
            track->SetPy(py2);
            track->SetPz(pz2);
         }
         delete track0;
      } else {   
         track = AddTrack(rnd);
      }   
   }
   return fNtracks;
}   

//______________________________________________________________________________
void AnaEvent::CreateEvents(Int_t nevents, const char *filename)
{
// Create nevents in one tree and put them in filename.
   TFile *hfile = new TFile(filename, "RECREATE", "Some AnaEvents...");
   TTree *tree  = new TTree("T", "Tree of AnaEvents");
   tree->SetAutoSave(1000000000);  // autosave when 1 Gbyte written
   Int_t bufsize = 16000;
   AnaEvent *event = new AnaEvent();
   TBranch *branch = tree->Branch("event", &event, bufsize,1);
   branch->SetAutoDelete(kFALSE);
   
   for (Int_t ev=0; ev<nevents; ev++) {
      Int_t ntracks = event->Build(ev);
      if (ev%100 == 0) printf("event: %d  ntracks=%d\n", ev, ntracks);
      tree->Fill();
   }   
   hfile->Write();
   tree->Print();
   hfile->Close();
}
Commit	Line	Data
16a89872	1	// ##### TO RUN THIS MACRO:
	2	// bash$ aliroot (due to AliInfo, AliError, ...)
	3	// root[0] gSystem->Load("libANALYSIS_NEW");
	4	// IN case you do not have the include path set to AliRoot includes:
	5	// root[1] gSystem->AddIncludePath("-I\"$ALICE_ROOT/include\"");
	6	// root[2] .L testEvent.C+;
	7	// root[3] generate();
	8	// root[4] filter_reco();
	9
	10	#include "TClonesArray.h"
	11	#include "TChain.h"
	12	#include "TH1.h"
	13	#include "TCanvas.h"
	14	#include "testEvent.h"
	15
	16	//============= First step: generate events
	17	void generate()
	18	{
	19	// Simple event generation
	20	AliAnalysisManager *mgr = new AliAnalysisManager();
	21	TaskGenerate *task = new TaskGenerate("gener");
	22	mgr->AddTask(task);
	23
	24	if (mgr->InitAnalysis()) {
	25	mgr->PrintStatus();
	26	mgr->ExecAnalysis();
	27	}
	28	delete mgr;
	29	}
	30
	31	//============= Second step: filter gammas; use TSelector functionality
	32	void filter_reco()
	33	{
	34	// Filter the input events having more than 100 gammas. Reconstruct pi0's
	35	// From gammas coming from the same vertex.
	36	// Get the input data as a chain
	37	TChain *chain = new TChain("T");
	38	chain->Add("event02000.root");
	39	chain->Add("event04000.root");
	40	chain->Add("event06000.root");
	41	chain->Add("event08000.root");
	42	chain->Add("event10000.root");
	43	// Create an analysis manager
	44	AliAnalysisManager *mgr = new AliAnalysisManager();
	45	// Create a filter task and register it
	46	TaskFilter *task1 = new TaskFilter("TaskFilter");
	47	mgr->AddTask(task1);
	48	// Create a reco task and register it
	49	TaskRecoPi0 *task2 = new TaskRecoPi0("TaskRecoPi0");
	50	mgr->AddTask(task2);
	51	// Create containers for input/output
	52	AliAnalysisDataContainer *cinput = mgr->CreateContainer("input0",
	53	TTree::Class(), AliAnalysisManager::kInputContainer);
	54	AliAnalysisDataContainer *coutput1 = mgr->CreateContainer("output0",
	55	TTree::Class(), AliAnalysisManager::kOutputContainer);
	56	AliAnalysisDataContainer *coutput2 = mgr->CreateContainer("output1",
	57	TList::Class(), AliAnalysisManager::kOutputContainer);
	58	AliAnalysisDataContainer *coutput = mgr->CreateContainer("output",
	59	TH1::Class(), AliAnalysisManager::kOutputContainer);
	60	// Connect containers to the task input/outputs
	61	mgr->ConnectInput(task1,0,cinput);
	62	mgr->ConnectOutput(task1,0,coutput1);
	63	mgr->ConnectOutput(task1,1,coutput2);
	64	mgr->ConnectInput(task2,0,coutput1);
65	mgr->ConnectOutput(task2,0,coutput);
66	// Connect input data
67	cinput->SetData(chain);
68	// Init analysis and start event loop
69	if (mgr->InitAnalysis()) {
70	mgr->PrintStatus();
71	chain->Process(mgr);
72	}
73	// delete mgr;
74	}
75
76	ClassImp(TaskGenerate)
77
78	//______________________________________________________________________________
79	void TaskGenerate::Exec(Option_t *)
80	{
81	// Generate 10k events in 5 files
82	AnaEvent::CreateEvents(2000, "event02000.root");
83	AnaEvent::CreateEvents(2000, "event04000.root");
84	AnaEvent::CreateEvents(2000, "event06000.root");
85	AnaEvent::CreateEvents(2000, "event08000.root");
86	AnaEvent::CreateEvents(2000, "event10000.root");
87	}
88
89	ClassImp(TaskFilter)
90
91	//______________________________________________________________________________
92	TaskFilter::TaskFilter(const char *name)
93	:AliAnalysisTask(name,""), fEvent(0), fOutput(0), fList(0), fHist1(0), fHist2(0)
94	{
95	// Constructor
96	// Input slot #0 works with a tree of events
97	DefineInput(0, TTree::Class());
98
99	// Output slot #0 writes into a tree, #1 produces a hisogram
100	DefineOutput(0, TTree::Class());
101	DefineOutput(1, TList::Class());
102	}
103
104	//______________________________________________________________________________
105	void TaskFilter::Init(Option_t *)
106	{
107	// Initialize branches.
108	printf(" Init %s\n", GetName());
109	if (!fEvent) {
110	// One should first check if the branch address was taken by some other task
111	char address = (char )GetBranchAddress(0, "event");
112	if (address) fEvent = (AnaEvent)(address);
113	if (!fEvent) {
114	fEvent = new AnaEvent();
115	SetBranchAddress(0, "event", &fEvent);
116	}
117	// The output tree will be written to gammas.root
118	TDirectory *dirsav = gDirectory;
119	// Open a file for output #0
120	OpenFile(0, "gammas.root", "RECREATE");
121	fOutput = new TTree("TGAM", "gammas");
122	TBranch *branch = fOutput->Branch("event", &fEvent, 18000,1);
123	branch->SetAutoDelete(kFALSE);
124	if (dirsav) dirsav->cd();
125	}
126	if (!fList) {
127	fList = new TList();
128	fHist1 = new TH1I("ntracks", "Number of tracks per event", 100, 0, 1000);
129	fHist1->SetLineColor(kRed);
130	fHist2 = new TH1I("ngammas", "Number of gammas per event", 100, 0, 1000);
131	fHist2->SetLineColor(kBlue);
132	fList->Add(fHist1);
133	fList->Add(fHist2);
134	}
135	}
136
137	//______________________________________________________________________________
138	void TaskFilter::Exec(Option_t *)
139	{
140	// Filtering.
141	TTree tinput = (TTree)GetInputData(0);
142	Long64_t ientry = tinput->GetReadEntry();
143	// In this case fEvent address is already connected to the input
144	if (!fEvent) return;
145	// First check multiplicity
146	Int_t ntracks = fEvent->GetNtracks();
147	// Loop tracks and get rid of non-gammas
148	AnaTrack *track;
149	Int_t igamma = 0;
150	for (Int_t i=0; i<ntracks; i++) {
151	track = fEvent->GetTrack(i);
152	if (track->GetMass() < 1.e-3) igamma++;
153	}
154	if (ientry%100 == 0) printf("TaskFilter -> Event %lld: %i tracks filtered %i gammas\n", ientry, ntracks, igamma);
155	fHist1->Fill(ntracks);
156	fHist2->Fill(igamma);
157	if (igamma > 100) {
158	fOutput->Fill();
159	PostData(0, fOutput);
160	}
161	PostData(1, fList);
162	}
163
164	//______________________________________________________________________________
165	void TaskFilter::Terminate(Option_t *)
166	{
167	// Draw some histogram at the end.
168	if (!gROOT->IsBatch()) {
169	fHist1->SetMaximum(2500);
170	fHist1->Draw();
171	fHist2->Draw("SAME");
172	}
173	}
174
175	ClassImp(TaskRecoPi0)
176
177	//______________________________________________________________________________
178	TaskRecoPi0::TaskRecoPi0(const char *name)
179	:AliAnalysisTask(name,""), fEvent(0), fGammas(0), fPions(0), fHist(0)
180	{
181	// Constructor
182	// Input slot #0 works with a tree of events
183	DefineInput(0, TTree::Class());
184
185	// Output slot #1 produces a hisogram
186	DefineOutput(0, TH1::Class());
187	}
188
189	//______________________________________________________________________________
190	TaskRecoPi0::~TaskRecoPi0()
191	{
192	// Dtor.
193	if (fEvent) delete fEvent;
194	if (fGammas) delete fGammas;
195	if (fPions) delete fPions;
196	}
197
198	//______________________________________________________________________________
199	void TaskRecoPi0::Init(Option_t *)
200	{
201	// Initialize branches.
202	printf(" Init %s\n", GetName());
203	if (!fEvent) {
204	// One should first check if the branch address was taken by some other task
205	char address = (char )GetBranchAddress(0, "event");
206	if (address) fEvent = (AnaEvent)(address);
207	if (!fEvent) {
208	fEvent = new AnaEvent();
209	SetBranchAddress(0, "event", &fEvent);
210	}
211	fGammas = new TObjArray();
212	fPions = new TObjArray();
213	}
214	if (!fHist) {
215	fHist = new TH1F("Pt_pi0", "Pt distribution for pi0's", 100, 0., 10.);
216	fHist->SetLineColor(kRed);
217	}
218	}
219
220	//______________________________________________________________________________
221	void TaskRecoPi0::Exec(Option_t *)
222	{
223	// Reconstruct Pi0's for one event
224	AnaTrack *track = 0;
225	Int_t ntracks = fEvent->GetNtracks();
226	Int_t ngamma = 0;
227	Int_t i,j;
228	// Clear containers
229	fGammas->Clear();
230	fPions->Delete();
231	fPions->Clear();
232	// Loop tracks and move gammas to gamma container
233	for (i=0; i<ntracks; i++) {
234	track = fEvent->GetTrack(i);
235	if (track->GetMass() < 1.e-3) {
236	fGammas->Add(track);
237	ngamma++;
238	}
239	}
240	printf("TaskRecoPi0 -> Tracks %i \n", ntracks);
241
242	// Loop gammas and check vertex position
243	Double_t v1[3], v2[3];
244	AnaTrack *tracko = 0;
245	Double_t cutoff = 0.001;
246	for (i=0; i<ngamma-1; i++) {
247	track = (AnaTrack*)fGammas->At(i);
248	v1[0] = track->GetVertex(0);
249	v1[1] = track->GetVertex(1);
250	v1[2] = track->GetVertex(2);
251	for (j=i+1; j<ngamma; j++) {
252	tracko = (AnaTrack*)fGammas->At(j);
253	v2[0] = tracko->GetVertex(0);
254	v2[1] = tracko->GetVertex(1);
255	v2[2] = tracko->GetVertex(2);
256	Double_t dist2 = (v2[0]-v1[0])*(v2[0]-v1[0])+
257	(v2[1]-v1[1])*(v2[1]-v1[1])+
258	(v2[2]-v1[2])*(v2[2]-v1[2]);
259	if (dist2>cutoff*cutoff) continue;
260	// We have found a pair candidate
261	Double_t px = track->GetPx()+tracko->GetPx();
262	Double_t py = track->GetPy()+tracko->GetPy();
263	Double_t pz = track->GetPz()+tracko->GetPz();
264	track = new AnaTrack(px,py,pz,0.135,0,v1[0],v1[1],v1[2]);
265	fPions->Add(track);
266	fHist->Fill(track->GetPt());
267	break;
268	}
269	}
270	PostData(0,fHist);
271	}
272
273	//______________________________________________________________________________
274	void TaskRecoPi0::Terminate(Option_t *)
275	{
276	// Draw some histogram at the end.
277	if (!gROOT->IsBatch()) {
278	new TCanvas("pi0", "Pt for pi0's", 800,600);
279	fHist->Draw();
280	}
281	}
282
283
284	ClassImp(AnaTrack)
285
286	//______________________________________________________________________________
287	AnaTrack::AnaTrack(Double_t random, Double_t *vertex)
288	{
289	// Constructor
290	Int_t itype;
291	if (random<0.3) itype = 1; // pi+
292	else if (random<0.6) itype = 2; // pi-
293	else if (random<0.9) itype = 3; // p
294	else if (random<0.95) itype = 4; // pi0
295	else itype = 5; // gamma
296	gRandom->Rannor(fPx, fPy);
297	Double_t vert_width = 0.1;
298
299	switch (itype) {
300	case 1:
301	fMass = 0.13957 + gRandom->Gaus(0.,0.001);
302	fCharge = 1;
303	break;
304	case 2:
305	fMass = 0.13957 + gRandom->Gaus(0.,0.001);
306	fCharge = -1;
307	break;
308	case 3:
309	fMass = 0.938 + gRandom->Gaus(0.,0.002);
310	fCharge = 1;
311	fPx *= 0.15;
312	fPy *= 0.15;
313	break;
314	case 4:
315	fMass = 0.135 + gRandom->Gaus(0.,0.001);
316	fCharge = 0;
317	fPx *= 0.8;
318	fPy *= 0.8;
319	vert_width = 10.;
320	break;
321	case 5:
322	fMass = 0.;
323	fCharge = 0;
324	fPx *= 0.5;
325	fPy *= 1.5;
326	break;
327	};
328	fPz = gRandom->Gaus(4., 2.);
329	if (vertex) {
330	fVertex[0] = vertex[0];
331	fVertex[1] = vertex[1];
332	fVertex[2] = vertex[2];
333	} else {
334	fVertex[0] = gRandom->Gaus(0,vert_width);
335	fVertex[1] = gRandom->Gaus(0,vert_width);
336	fVertex[2] = gRandom->Gaus(0,0.01);
337	}
338	}
339
340	//______________________________________________________________________________
341	Bool_t AnaTrack::Decay(Double_t &px1, Double_t &py1, Double_t &pz1,
342	Double_t &px2, Double_t &py2, Double_t &pz2)
343	{
344	// Decay a pi0 in 2 gammas.
345	if (fCharge != 0) return kFALSE;
346	if (fMass<0.132 \|\| fMass>0.138) return kFALSE;
347	Double_t phi1 = 2.TMath::Pi()gRandom->Rndm(); // [0,2*pi]
348	Double_t phi2 = phi1 + TMath::Pi();
349	if (phi2 > 2.TMath::Pi()) phi2 -= 2.TMath::Pi();
350	Double_t r2 = gRandom->Rndm();
351	Double_t theta1 = TMath::ACos(1.-2.*r2);
352	Double_t p0 = GetP();
353	Double_t m0 = 0.135;
354	Double_t p1 = 0.5(p0(1-2r2)+TMath::Sqrt(p0p0(1-2r2)(1-2r2)+2m0m0));
355	Double_t p2 = TMath::Sqrt(p0p0+m0m0-p1*p1);
356	Double_t theta2 = TMath::ACos((p0-p1(1-2r2))/p2);
357	// Px, Py and Pz in the reference frame of the pion
358	px1 = p1 * TMath::Sin(theta1)*TMath::Cos(phi1);
359	px2 = p2 * TMath::Sin(theta2)*TMath::Cos(phi2);
360	py1 = p1 * TMath::Sin(theta1)*TMath::Sin(phi1);
361	py2 = p2 * TMath::Sin(theta2)*TMath::Sin(phi2);
362	pz1 = p1 * TMath::Cos(theta1);
363	pz2 = p2 * TMath::Cos(theta2);
364	Double_t phi = TMath::ATan2(fPy, fPx) * TMath::RadToDeg();
365	Double_t theta = TMath::ACos(GetPt()/p0) * TMath::RadToDeg();
366	TGeoRotation r("rot", phi+90., theta, 0.);
367	Double_t loc[3], vect[3];
368	p0 = TMath::Sqrt(px1px1+py1py1+pz1*pz1);
369	loc[0] = px1/p0;
370	loc[1] = py1/p0;
371	loc[2] = pz1/p0;
372	r.LocalToMasterVect(loc, vect);
373	px1 = vect[0]*p0;
374	py1 = vect[1]*p0;
375	pz1 = vect[2]*p0;
376	// t1 = new AnaTrack(1., fVertex);
377	p0 = TMath::Sqrt(px2px2+py2py2+pz2*pz2);
378	loc[0] = px2/p0;
379	loc[1] = py2/p0;
380	loc[2] = pz2/p0;
381	r.LocalToMasterVect(loc, vect);
382	px2 = vect[0]*p0;
383	py2 = vect[1]*p0;
384	pz2 = vect[2]*p0;
385	// t2 = new AnaTrack(1., fVertex);
386	return kTRUE;
387	}
388
389	//______________________________________________________________________________
390	ClassImp(AnaEvent)
391
392	TClonesArray *AnaEvent::fgTracks = 0;
393
394	//______________________________________________________________________________
395	AnaEvent::AnaEvent()
396	{
397	// Ctor
398	if (!fgTracks) fgTracks = new TClonesArray("AnaTrack", 2000);
399	fTracks = fgTracks;
400	fEventNumber = 0;
401	fNtracks = 0;
402	}
403
404	//______________________________________________________________________________
405	AnaTrack AnaEvent::AddTrack(Double_t rnd, Double_t vert)
406	{
407	// Add a random track
408	// printf("track %d\n", fNtracks);
409	TClonesArray &tracks = *fTracks;
410	AnaTrack *track = new(tracks[fNtracks++]) AnaTrack(rnd, vert);
411	return track;
412	}
413
414	//______________________________________________________________________________
415	void AnaEvent::Clear(Option_t *)
416	{
417	// Clears current event.
418	fTracks->Clear();
419	fNtracks = 0;
420	fEventNumber = 0;
421	}
422
423	//______________________________________________________________________________
424	Int_t AnaEvent::Build(Int_t ev)
425	{
426	// Create a random event
427	Clear();
428	fEventNumber = ev;
429	Int_t ntracks = Int_t(gRandom->Gaus(500., 100.));
430	if (ntracks < 1) ntracks = 1;
431	if (ntracks>1000) ntracks = 1000;
432	AnaTrack track, track0;
433	for (Int_t i=0; i<ntracks; i++) {
434	Double_t rnd = gRandom->Rndm();
435	if (rnd>=0.90 && rnd<0.95) {
436	// Pi0 -> decay the track in 2 gammas
437	track0 = new AnaTrack(rnd);
438	Double_t vert[3];
439	vert[0] = track0->GetVertex(0);
440	vert[1] = track0->GetVertex(1);
441	vert[2] = track0->GetVertex(2);
442	Double_t px1,py1,pz1,px2,py2,pz2;
443	if (track0->Decay(px1,py1,pz1,px2,py2,pz2)) {
444	track = AddTrack(1.,vert);
445	track->SetPx(px1);
446	track->SetPy(py1);
447	track->SetPz(pz1);
448	track = AddTrack(1.,vert);
449	track->SetPx(px2);
450	track->SetPy(py2);
451	track->SetPz(pz2);
452	}
453	delete track0;
454	} else {
455	track = AddTrack(rnd);
456	}
457	}
458	return fNtracks;
459	}
460
461	//______________________________________________________________________________
462	void AnaEvent::CreateEvents(Int_t nevents, const char *filename)
463	{
464	// Create nevents in one tree and put them in filename.
465	TFile *hfile = new TFile(filename, "RECREATE", "Some AnaEvents...");
466	TTree *tree = new TTree("T", "Tree of AnaEvents");
467	tree->SetAutoSave(1000000000); // autosave when 1 Gbyte written
468	Int_t bufsize = 16000;
469	AnaEvent *event = new AnaEvent();
470	TBranch *branch = tree->Branch("event", &event, bufsize,1);
471	branch->SetAutoDelete(kFALSE);
472
473	for (Int_t ev=0; ev<nevents; ev++) {
474	Int_t ntracks = event->Build(ev);
475	if (ev%100 == 0) printf("event: %d ntracks=%d\n", ev, ntracks);
476	tree->Fill();
477	}
478	hfile->Write();
479	tree->Print();
480	hfile->Close();
481	}
482