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[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
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fe4da5cc 1#include "AliGenerator.h"
2#include "AliGenPythia.h"
3#include "TGeant3.h"
4#include "AliRun.h"
5#include "AliPythia.h"
6#include <TDirectory.h>
7#include <TFile.h>
8#include <TTree.h>
9#include <stdlib.h>
10#include <AliPythia.h>
11#include <TMCParticle.h>
12#include <GParticle.h>
13 ClassImp(AliGenPythia)
14
15AliGenPythia::AliGenPythia()
16 :AliGenerator()
17{
18}
19
20AliGenPythia::AliGenPythia(Int_t npart)
21 :AliGenerator(npart)
22{
23// default charm production at 5. 5 TeV
24// semimuonic decay
25// structure function GRVHO
26//
27 fXsection = 0.;
28 fParentSelect.Set(5);
29 fChildSelect.Set(5);
30 for (Int_t i=0; i<5; i++) fParentSelect[i]=fChildSelect[i]=0;
31 SetProcess();
32 SetStrucFunc();
33 ForceDecay();
34 SetPtHard();
35 SetEnergyCMS();
36}
37
38AliGenPythia::~AliGenPythia()
39{
40}
41
42void AliGenPythia::Init()
43{
44 SetMC(new AliPythia());
45 fPythia=(AliPythia*) fgMCEvGen;
46//
47 fParentWeight=1./Float_t(fNpart);
48//
49// Forward Paramters to the AliPythia object
50 fPythia->DefineParticles();
51 fPythia->ForceDecay(fForceDecay);
52 fPythia->SetCKIN(3,fPtHardMin);
53 fPythia->SetCKIN(4,fPtHardMax);
54 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
55 fPythia->LuList(0);
56 fPythia->PyStat(2);
57// Parent and Children Selection
58 switch (fProcess)
59 {
60 case charm:
61
62 fParentSelect[0]=411;
63 fParentSelect[1]=421;
64 fParentSelect[2]=431;
65 fParentSelect[3]=4122;
66 break;
67 case charm_unforced:
68
69 fParentSelect[0]=411;
70 fParentSelect[1]=421;
71 fParentSelect[2]=431;
72 fParentSelect[3]=4122;
73 break;
74 case beauty:
75 fParentSelect[0]=511;
76 fParentSelect[1]=521;
77 fParentSelect[2]=531;
78 fParentSelect[3]=5122;
79 break;
80 case beauty_unforced:
81 fParentSelect[0]=511;
82 fParentSelect[1]=521;
83 fParentSelect[2]=531;
84 fParentSelect[3]=5122;
85 break;
86 case jpsi_chi:
87 case jpsi:
88 fParentSelect[0]=443;
89 break;
90 }
91
92 switch (fForceDecay)
93 {
94 case semielectronic:
95 case dielectron:
96 case b_jpsi_dielectron:
97 case b_psip_dielectron:
98 fChildSelect[0]=11;
99 break;
100 case semimuonic:
101 case dimuon:
102 case b_jpsi_dimuon:
103 case b_psip_dimuon:
104 fChildSelect[0]=13;
105 break;
106 }
107}
108
109void AliGenPythia::Generate()
110{
111 AliMC* pMC = AliMC::GetMC();
112
113 Float_t polar[3] = {0,0,0};
114 Float_t origin[3]= {0,0,0};
115 Float_t origin0[3]= {0,0,0};
116 Float_t p[3], random[6];
117
118
119//
120 printf("Generate event");
121 Int_t nt=0;
122 Int_t jev=0;
123 Int_t j;
124
125 fTrials=0;
126 for (j=0;j<3;j++) origin0[j]=fOrigin[j];
127 if(fVertexSmear==perEvent) {
128 pMC->Rndm(random,6);
129 for (j=0;j<3;j++) {
130 origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
131 TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
132 fPythia->SetMSTP(151,0);
133 }
134 } else if (fVertexSmear==perTrack) {
135 fPythia->SetMSTP(151,0);
136 for (j=0;j<3;j++) {
137 fPythia->SetPARP(151+j, fOsigma[j]*10.);
138 }
139 }
140
141
142 while(1)
143 {
144 fPythia->PyEvnt();
145 fTrials++;
146 TObjArray* particles = fPythia->GetPrimaries() ;
147 Int_t np = particles->GetEntriesFast();
148 printf("\n **************************************************%d\n",np);
149 Int_t nc=0;
150 if (np == 0 ) continue;
151 for (Int_t i = 0; i<np; i++) {
152 TMCParticle * iparticle = (TMCParticle *) particles->At(i);
153 Int_t kf = iparticle->GetKF();
154 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
155//
156// Parent
157 if (ParentSelected(TMath::Abs(kf))) {
158
159 if (KinematicSelection(iparticle)) {
160 nc++;
161//
162// store parent track information
163 p[0]=iparticle->GetPx();
164 p[1]=iparticle->GetPy();
165 p[2]=iparticle->GetPz();
166 origin[0]=origin0[0]+iparticle->GetVx()/10;
167 origin[1]=origin0[1]+iparticle->GetVy()/10;
168 origin[2]=origin0[2]+iparticle->GetVz()/10;
169
170 Int_t ifch=iparticle->GetFirstChild();
171 Int_t ilch=iparticle->GetLastChild();
172 if (ifch !=0 && ilch !=0) {
173 gAlice->SetTrack(0,-1,fPythia->GetGeantCode(kf),
174 p,origin,polar,
175 0,"Primary",nt,fParentWeight);
176 Int_t iparent = nt;
177//
178// Children
179
180 for (Int_t j=ifch; j<=ilch; j++)
181 {
182 TMCParticle * ichild =
183 (TMCParticle *) particles->At(j-1);
184 Int_t kf = ichild->GetKF();
185//
186//
187 if (ChildSelected(TMath::Abs(kf))) {
188 Int_t kg=fPythia->GetGeantCode(kf);
189 origin[0]=ichild->GetVx();
190 origin[1]=ichild->GetVy();
191 origin[2]=ichild->GetVz();
192 p[0]=ichild->GetPx();
193 p[1]=ichild->GetPy();
194 p[2]=ichild->GetPz();
195 Float_t tof=ichild->GetTime();
196 gAlice->SetTrack(1, iparent, kg,
197 p,origin,polar,
198 tof,"Decay",nt,fChildWeight);
199 gAlice->KeepTrack(nt);
200 } // select child
201 } // child loop
202 }
203 } // kinematic selection
204 } // select particle
205 } // particles
206 if (nc > 0) {
207 jev++;
208 if (jev >= fNpart) {
209 fKineBias=Float_t(fNpart)/Float_t(fTrials);
210 printf("\n Trials: %i\n",fTrials);
211 break;
212 }
213 }
214 } // event loop
215// adjust weight due to kinematic selection
216 AdjustWeights();
217// get cross-section
218 fXsection=fPythia->GetPARI(1);
219}
220
221Bool_t AliGenPythia::ParentSelected(Int_t ip)
222{
223 for (Int_t i=0; i<5; i++)
224 {
225 if (fParentSelect[i]==ip) return kTRUE;
226 }
227 return kFALSE;
228}
229
230Bool_t AliGenPythia::ChildSelected(Int_t ip)
231{
232 for (Int_t i=0; i<5; i++)
233 {
234 if (fChildSelect[i]==ip) return kTRUE;
235 }
236 return kFALSE;
237}
238
239Bool_t AliGenPythia::KinematicSelection(TMCParticle *particle)
240{
241 Float_t px=particle->GetPx();
242 Float_t py=particle->GetPy();
243 Float_t pz=particle->GetPz();
244 Float_t e=particle->GetEnergy();
245
246//
247// transverse momentum cut
248 Float_t pt=TMath::Sqrt(px*px+py*py);
249 if (pt > fPtMax || pt < fPtMin)
250 {
251// printf("\n failed pt cut %f %f %f \n",pt,fPtMin,fPtMax);
252 return kFALSE;
253 }
254//
255// momentum cut
256 Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
257 if (p > fPMax || p < fPMin)
258 {
259// printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
260 return kFALSE;
261 }
262
263//
264// theta cut
265 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
266 if (theta > fThetaMax || theta < fThetaMin)
267 {
268// printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
269 return kFALSE;
270 }
271
272//
273// rapidity cut
274 Float_t y = 0.5*TMath::Log((e+pz)/(e-pz));
275 if (y > fYMax || y < fYMin)
276 {
277// printf("\n failed y cut %f %f %f \n",y,fYMin,fYMax);
278 return kFALSE;
279 }
280
281//
282// phi cut
283 Float_t phi=Float_t(TMath::ATan2(Double_t(py),Double_t(px)))+TMath::Pi();
284 if (phi > fPhiMax || phi < fPhiMin)
285 {
286// printf("\n failed phi cut %f %f %f \n",phi,fPhiMin,fPhiMax);
287 return kFALSE;
288 }
289
290 return kTRUE;
291}
292void AliGenPythia::AdjustWeights()
293{
294 TClonesArray *PartArray = gAlice->Particles();
295 GParticle *Part;
296 Int_t ntrack=gAlice->GetNtrack();
297 for (Int_t i=0; i<ntrack; i++) {
298 Part= (GParticle*) PartArray->UncheckedAt(i);
299 Part->SetWgt(Part->GetWgt()*fKineBias);
300 }
301}
302
303
304
305
306