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3928b038 | 1 | // Example: generation of kinematics tree with selected properties. |
2 | // Below we select events containing the decays D* -> D0 pi, D0 -> K- pi+ | |
3 | // inside the barrel part of the ALICE detector (45 < theta < 135) | |
4 | ||
5 | #if !defined(__CINT__) || defined(__MAKECINT__) | |
6 | #include <Riostream.h> | |
7 | #include <TH1F.h> | |
8 | #include <TStopwatch.h> | |
9 | #include <TDatime.h> | |
10 | #include <TRandom.h> | |
11 | #include <TDatabasePDG.h> | |
12 | #include <TParticle.h> | |
13 | #include <TArrayI.h> | |
14 | ||
15 | #include "AliGenerator.h" | |
16 | #include "AliPDG.h" | |
17 | #include "AliRunLoader.h" | |
18 | #include "AliRun.h" | |
19 | #include "AliStack.h" | |
20 | #include "AliHeader.h" | |
21 | #include "PYTHIA6/AliGenPythia.h" | |
22 | #include "PYTHIA6/AliPythia.h" | |
23 | #endif | |
24 | ||
25 | Float_t EtaToTheta(Float_t arg); | |
26 | void GetFinalDecayProducts(Int_t ind, AliStack & stack , TArrayI & ar); | |
27 | ||
28 | void fastGen(Int_t nev = 1, char* filename = "galice.root") | |
29 | { | |
30 | AliPDG::AddParticlesToPdgDataBase(); | |
31 | TDatabasePDG* pPdg = TDatabasePDG::Instance(); | |
32 | ||
33 | ||
34 | ||
35 | // Run loader | |
36 | AliRunLoader* rl = AliRunLoader::Open("galice.root","FASTRUN","recreate"); | |
37 | ||
38 | rl->SetCompressionLevel(2); | |
39 | rl->SetNumberOfEventsPerFile(nev); | |
40 | rl->LoadKinematics("RECREATE"); | |
41 | rl->MakeTree("E"); | |
42 | gAlice->SetRunLoader(rl); | |
43 | ||
44 | // Create stack | |
45 | rl->MakeStack(); | |
46 | AliStack* stack = rl->Stack(); | |
47 | ||
48 | // Header | |
49 | AliHeader* header = rl->GetHeader(); | |
50 | ||
51 | // Create and Initialize Generator | |
52 | ||
53 | // Example of charm generation taken from Config_PythiaHeavyFlavours.C | |
54 | AliGenPythia *gener = new AliGenPythia(-1); | |
55 | gener->SetEnergyCMS(14000.); | |
56 | gener->SetMomentumRange(0,999999); | |
57 | gener->SetPhiRange(0., 360.); | |
58 | gener->SetThetaRange(0.,180.); | |
59 | // gener->SetProcess(kPyCharmppMNR); // Correct Pt distribution, wrong mult | |
60 | gener->SetProcess(kPyMb); // Correct multiplicity, wrong Pt | |
61 | gener->SetStrucFunc(kCTEQ4L); | |
62 | gener->SetPtHard(2.1,-1.0); | |
63 | gener->SetFeedDownHigherFamily(kFALSE); | |
64 | gener->SetStack(stack); | |
65 | gener->Init(); | |
66 | ||
67 | // Go to galice.root | |
68 | rl->CdGAFile(); | |
69 | ||
70 | // Forbid some decays. Do it after gener->Init(0, because | |
71 | // the initialization of the generator includes reading of the decay table. | |
72 | ||
73 | AliPythia * py= AliPythia::Instance(); | |
74 | py->SetMDME(731,1,0); //forbid D*+->D+ + pi0 | |
75 | py->SetMDME(732,1,0);//forbid D*+->D+ + gamma | |
76 | ||
77 | // Forbid all D0 decays except D0->K- pi+ | |
78 | for(Int_t d=741; d<=756; d++){ | |
79 | py->SetMDME(d,1,0); | |
80 | } | |
81 | // decay 757 is D0->K- pi+ | |
82 | for(Int_t d=758; d<=801; d++){ | |
83 | py->SetMDME(d,1,0); | |
84 | } | |
85 | ||
86 | // | |
87 | // Event Loop | |
88 | // | |
89 | ||
90 | TStopwatch timer; | |
91 | timer.Start(); | |
92 | for (Int_t iev = 0; iev < nev; iev++) { | |
93 | ||
94 | cout <<"Event number "<< iev << endl; | |
95 | ||
96 | // Initialize event | |
97 | header->Reset(0,iev); | |
98 | rl->SetEventNumber(iev); | |
99 | stack->Reset(); | |
100 | rl->MakeTree("K"); | |
101 | ||
102 | // Generate event | |
103 | Int_t nprim = 0; | |
104 | Int_t ntrial = 0; | |
105 | Int_t minmult = 1000; | |
106 | Int_t ndstar = 0; | |
107 | ||
108 | ||
109 | ||
110 | //------------------------------------------------------------------------------------- | |
111 | ||
112 | while(!ndstar) { | |
113 | // Selection of events with multiplicity | |
114 | // bigger than "minmult" | |
115 | stack->Reset(); | |
116 | gener->Generate(); | |
117 | ntrial++; | |
118 | nprim = stack->GetNprimary(); | |
119 | ||
120 | for(Int_t ipart =0; ipart < nprim; ipart++){ | |
121 | TParticle * part = stack->Particle(ipart); | |
122 | if(part) { | |
123 | ||
124 | if (TMath::Abs(part->GetPdgCode())== 413) { | |
125 | ||
126 | TArrayI daughtersId; | |
127 | ||
128 | GetFinalDecayProducts(ipart,*stack,daughtersId); | |
129 | ||
130 | Bool_t kineOK = kTRUE; | |
131 | ||
132 | Double_t thetaMin = TMath::Pi()/4; | |
133 | Double_t thetaMax = 3*TMath::Pi()/4; | |
134 | ||
135 | for (Int_t id=1; id<=daughtersId[0]; id++) { | |
136 | TParticle * daughter = stack->Particle(daughtersId[id]); | |
137 | if (!daughter) { | |
138 | kineOK = kFALSE; | |
139 | break; | |
140 | } | |
141 | ||
142 | Double_t theta = daughter->Theta(); | |
143 | if (theta<thetaMin || theta>thetaMax) { | |
144 | kineOK = kFALSE; | |
145 | break; | |
146 | } | |
147 | } | |
148 | ||
149 | if (!kineOK) continue; | |
150 | ||
151 | part->Print(); | |
152 | ndstar++; | |
153 | ||
154 | } | |
155 | } | |
156 | } | |
157 | } | |
158 | ||
159 | cout << "Number of particles " << nprim << endl; | |
160 | cout << "Number of trials " << ntrial << endl; | |
161 | ||
162 | // Finish event | |
163 | header->SetNprimary(stack->GetNprimary()); | |
164 | header->SetNtrack(stack->GetNtrack()); | |
165 | ||
166 | // I/O | |
167 | stack->FinishEvent(); | |
168 | header->SetStack(stack); | |
169 | rl->TreeE()->Fill(); | |
170 | rl->WriteKinematics("OVERWRITE"); | |
171 | ||
172 | } // event loop | |
173 | timer.Stop(); | |
174 | timer.Print(); | |
175 | ||
176 | // Termination | |
177 | // Generator | |
178 | gener->FinishRun(); | |
179 | // Stack | |
180 | stack->FinishRun(); | |
181 | // Write file | |
182 | rl->WriteHeader("OVERWRITE"); | |
183 | gener->Write(); | |
184 | rl->Write(); | |
185 | } | |
186 | ||
187 | ||
188 | ||
189 | Float_t EtaToTheta(Float_t arg){ | |
190 | return (180./TMath::Pi())*2.*atan(exp(-arg)); | |
191 | } | |
192 | ||
193 | ||
194 | void GetFinalDecayProducts(Int_t ind, AliStack & stack , TArrayI & ar){ | |
195 | ||
196 | // Recursive algorithm to get the final decay products of a particle | |
197 | // | |
198 | // ind is the index of the particle in the AliStack | |
199 | // stack is the particle stack from the generator | |
200 | // ar contains the indexes of the final decay products | |
201 | // ar[0] is the number of final decay products | |
202 | ||
203 | if (ind<0 || ind>stack.GetNtrack()) { | |
204 | cerr << "Invalid index of the particle " << ind << endl; | |
205 | return; | |
206 | } | |
207 | if (ar.GetSize()==0) { | |
208 | ar.Set(10); | |
209 | ar[0] = 0; | |
210 | } | |
211 | ||
212 | TParticle * part = stack.Particle(ind); | |
213 | ||
214 | Int_t iFirstDaughter = part->GetFirstDaughter(); | |
215 | if( iFirstDaughter<0) { | |
216 | // This particle is a final decay product, add its index to the array | |
217 | ar[0]++; | |
218 | if (ar.GetSize() <= ar[0]) ar.Set(ar.GetSize()+10); // resize if needed | |
219 | ar[ar[0]] = ind; | |
220 | return; | |
221 | } | |
222 | ||
223 | Int_t iLastDaughter = part->GetLastDaughter(); | |
224 | ||
225 | for (Int_t id=iFirstDaughter; id<=iLastDaughter;id++) { | |
226 | // Now search for final decay products of the daughters | |
227 | GetFinalDecayProducts(id,stack,ar); | |
228 | } | |
229 | } |