Possibility to have different binaries in the same tree introduced
[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
1 #include "AliGenerator.h"
2 #include "AliGenPythia.h"
3 #include "AliRun.h"
4 #include "AliPythia.h"
5 #include <TDirectory.h>
6 #include <TFile.h>
7 #include <TTree.h>
8 #include <stdlib.h>
9 #include <AliPythia.h>
10 #include <TParticle.h>
11 //#include <GParticle.h>
12  ClassImp(AliGenPythia)
13
14 AliGenPythia::AliGenPythia()
15                  :AliGenerator()
16 {
17 }
18
19 AliGenPythia::AliGenPythia(Int_t npart)
20                  :AliGenerator(npart)
21 {
22 // default charm production at 5. 5 TeV
23 // semimuonic decay
24 // structure function GRVHO
25 //
26     fXsection  = 0.;
27     fParentSelect.Set(5);
28     fChildSelect.Set(5);
29     for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
30     SetProcess();
31     SetStrucFunc();
32     ForceDecay();
33     SetPtHard();
34     SetEnergyCMS();
35 }
36
37 AliGenPythia::~AliGenPythia()
38 {
39 }
40
41 void AliGenPythia::Init()
42 {
43     SetMC(new AliPythia());
44     fPythia=(AliPythia*) fgMCEvGen;
45 //
46     fParentWeight=1./Float_t(fNpart);
47 //
48 //  Forward Paramters to the AliPythia object
49     fPythia->DefineParticles();
50     fPythia->SetCKIN(3,fPtHardMin);
51     fPythia->SetCKIN(4,fPtHardMax);    
52     fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
53     fPythia->ForceDecay(fForceDecay);
54     fPythia->LuList(0);
55     fPythia->PyStat(2);
56 //  Parent and Children Selection
57     switch (fProcess) 
58     {
59     case charm:
60
61         fParentSelect[0]=411;
62         fParentSelect[1]=421;
63         fParentSelect[2]=431;
64         fParentSelect[3]=4122;  
65         break;
66     case charm_unforced:
67
68         fParentSelect[0]=411;
69         fParentSelect[1]=421;
70         fParentSelect[2]=431;
71         fParentSelect[3]=4122;  
72         break;
73     case beauty:
74         fParentSelect[0]=511;
75         fParentSelect[1]=521;
76         fParentSelect[2]=531;
77         fParentSelect[3]=5122;  
78         break;
79     case beauty_unforced:
80         fParentSelect[0]=511;
81         fParentSelect[1]=521;
82         fParentSelect[2]=531;
83         fParentSelect[3]=5122;  
84         break;
85     case jpsi_chi:
86     case jpsi:
87         fParentSelect[0]=443;
88         break;
89     case mb:
90         break;
91     }
92
93     switch (fForceDecay) 
94     {
95     case semielectronic:
96     case dielectron:
97     case b_jpsi_dielectron:
98     case b_psip_dielectron:
99         fChildSelect[0]=11;     
100         break;
101     case semimuonic:
102     case dimuon:
103     case b_jpsi_dimuon:
104     case b_psip_dimuon:
105     case pitomu:
106     case katomu:
107         fChildSelect[0]=13;
108         break;
109     }
110 }
111
112 void AliGenPythia::Generate()
113 {
114
115     Float_t polar[3] =   {0,0,0};
116     Float_t origin[3]=   {0,0,0};
117     Float_t origin_p[3]= {0,0,0};
118     Float_t origin0[3]=  {0,0,0};
119     Float_t p[3], p_p[4], random[6];
120 //  converts from mm/c to s
121     const Float_t kconv=0.001/2.999792458e8;
122     
123     
124 //
125     Int_t nt=0;
126     Int_t nt_p=0;
127     Int_t jev=0;
128     Int_t j;
129     
130     fTrials=0;
131     for (j=0;j<3;j++) origin0[j]=fOrigin[j];
132     if(fVertexSmear==perEvent) {
133         gMC->Rndm(random,6);
134         for (j=0;j<3;j++) {
135             origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
136                 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
137             fPythia->SetMSTP(151,0);
138         }
139     } else if (fVertexSmear==perTrack) {
140         fPythia->SetMSTP(151,0);
141         for (j=0;j<3;j++) {
142             fPythia->SetPARP(151+j, fOsigma[j]*10.);
143         }
144     }
145     while(1)
146     {
147         fPythia->PyEvnt();
148         fTrials++;
149         TObjArray* particles = fPythia->ImportParticles();
150         Int_t np = particles->GetEntriesFast();
151         printf("\n **************************************************%d\n",np);
152         Int_t nc=0;
153         if (np == 0 ) continue;
154         if (fProcess != mb) {
155             for (Int_t i = 0; i<np; i++) {
156                 TParticle *  iparticle = (TParticle *) particles->At(i);
157                 Int_t kf = iparticle->GetPdgCode();
158                 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;     
159 //
160 // Parent
161                 if (ParentSelected(TMath::Abs(kf))) {
162                     if (KinematicSelection(iparticle)) {
163                         if (nc==0) {
164 //
165 // Store information concerning the hard scattering process
166 //
167                             Float_t mass_p = fPythia->GetPARI(13);
168                             Float_t   pt_p = fPythia->GetPARI(17);
169                             Float_t    y_p = fPythia->GetPARI(37);
170                             Float_t  xmt_p = sqrt(pt_p*pt_p+mass_p*mass_p);
171                             Float_t     ty = Float_t(TMath::TanH(y_p));
172                             p_p[0] = pt_p;
173                             p_p[1] = 0;
174                             p_p[2] = xmt_p*ty/sqrt(1.-ty*ty);
175                             p_p[3] = mass_p;
176                             gAlice->SetTrack(0,-1,-1,
177                                              p_p,origin_p,polar,
178                                              0,"Hard Scat.",nt_p,fParentWeight);
179                             gAlice->KeepTrack(nt_p);
180                         }
181                         nc++;
182 //
183 // store parent track information
184                         p[0]=iparticle->Px();
185                         p[1]=iparticle->Py();
186                         p[2]=iparticle->Pz();
187                         origin[0]=origin0[0]+iparticle->Vx()/10;
188                         origin[1]=origin0[1]+iparticle->Vy()/10;
189                         origin[2]=origin0[2]+iparticle->Vz()/10;
190
191                         Int_t ifch=iparticle->GetFirstDaughter();
192                         Int_t ilch=iparticle->GetLastDaughter();        
193                         if (ifch !=0 && ilch !=0) {
194                             gAlice->SetTrack(0,nt_p,kf,
195                                              p,origin,polar,
196                                              0,"Primary",nt,fParentWeight);
197                             gAlice->KeepTrack(nt);
198                             Int_t iparent = nt;
199 //
200 // Children         
201
202                             for (Int_t j=ifch; j<=ilch; j++)
203                             {
204                                 TParticle *  ichild = 
205                                     (TParticle *) particles->At(j-1);
206                                 Int_t kf = ichild->GetPdgCode();
207 //
208 // 
209                                 if (ChildSelected(TMath::Abs(kf))) {
210                                     origin[0]=ichild->Vx();
211                                     origin[1]=ichild->Vy();
212                                     origin[2]=ichild->Vz();             
213                                     p[0]=ichild->Px();
214                                     p[1]=ichild->Py();
215                                     p[2]=ichild->Pz();
216                                     Float_t tof=kconv*ichild->T();
217                                     gAlice->SetTrack(fTrackIt, iparent, kf,
218                                                      p,origin,polar,
219                                                      tof,"Decay",nt,fChildWeight);
220                                     gAlice->KeepTrack(nt);
221                                 } // select child
222                             } // child loop
223                         }
224                     } // kinematic selection
225                 } // select particle
226             } // particle loop
227         } else {
228             for (Int_t i = 0; i<np; i++) {
229                 TParticle *  iparticle = (TParticle *) particles->At(i);
230                 Int_t kf = iparticle->GetPdgCode();
231                 Int_t ks = iparticle->GetStatusCode();
232                 if (ks==1 && kf!=0 && KinematicSelection(iparticle)) {
233                         nc++;
234 //
235 // store track information
236                         p[0]=iparticle->Px();
237                         p[1]=iparticle->Py();
238                         p[2]=iparticle->Pz();
239                         origin[0]=origin0[0]+iparticle->Vx()/10;
240                         origin[1]=origin0[1]+iparticle->Vy()/10;
241                         origin[2]=origin0[2]+iparticle->Vz()/10;
242                         Float_t tof=kconv*iparticle->T();
243                         gAlice->SetTrack(fTrackIt,-1,kf,p,origin,polar,
244                                          tof,"Primary",nt);
245                         gAlice->KeepTrack(nt);
246                 } // select particle
247             } // particle loop 
248             printf("\n I've put %i particles on the stack \n",nc);
249         } // mb ?
250         if (nc > 0) {
251             jev+=nc;
252             if (jev >= fNpart) {
253                 fKineBias=Float_t(fNpart)/Float_t(fTrials);
254                 printf("\n Trials: %i\n",fTrials);
255                 break;
256             }
257         }
258     } // event loop
259 //  adjust weight due to kinematic selection
260     AdjustWeights();
261 //  get cross-section
262     fXsection=fPythia->GetPARI(1);
263 }
264
265 Bool_t AliGenPythia::ParentSelected(Int_t ip)
266 {
267     for (Int_t i=0; i<5; i++)
268     {
269         if (fParentSelect[i]==ip) return kTRUE;
270     }
271     return kFALSE;
272 }
273
274 Bool_t AliGenPythia::ChildSelected(Int_t ip)
275 {
276     for (Int_t i=0; i<5; i++)
277     {
278         if (fChildSelect[i]==ip) return kTRUE;
279     }
280     return kFALSE;
281 }
282
283 Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
284 {
285     Float_t px=particle->Px();
286     Float_t py=particle->Py();
287     Float_t pz=particle->Pz();
288     Float_t  e=particle->Energy();
289
290 //
291 //  transverse momentum cut    
292     Float_t pt=TMath::Sqrt(px*px+py*py);
293     if (pt > fPtMax || pt < fPtMin) 
294     {
295 //      printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
296         return kFALSE;
297     }
298 //
299 // momentum cut
300     Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
301     if (p > fPMax || p < fPMin) 
302     {
303 //      printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
304         return kFALSE;
305     }
306     
307 //
308 // theta cut
309     Float_t  theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
310     if (theta > fThetaMax || theta < fThetaMin) 
311     {
312 //      printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
313         return kFALSE;
314     }
315
316 //
317 // rapidity cut
318     Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
319     if (y > fYMax || y < fYMin)
320     {
321 //      printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
322         return kFALSE;
323     }
324
325 //
326 // phi cut
327     Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
328     if (phi > fPhiMax || phi < fPhiMin)
329     {
330 //      printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
331         return kFALSE;
332     }
333
334     return kTRUE;
335 }
336 void AliGenPythia::AdjustWeights()
337 {
338     TClonesArray *PartArray = gAlice->Particles();
339     TParticle *Part;
340     Int_t ntrack=gAlice->GetNtrack();
341     for (Int_t i=0; i<ntrack; i++) {
342         Part= (TParticle*) PartArray->UncheckedAt(i);
343         Part->SetWeight(Part->GetWeight()*fKineBias);
344     }
345 }
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