Adding doc and etc to save
[u/mrichter/AliRoot.git] / EVGEN / AliGenPythia.cxx
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fe4da5cc 1#include "AliGenerator.h"
2#include "AliGenPythia.h"
fe4da5cc 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>
1578254f 10#include <TParticle.h>
11//#include <GParticle.h>
fe4da5cc 12 ClassImp(AliGenPythia)
13
14AliGenPythia::AliGenPythia()
15 :AliGenerator()
16{
17}
18
19AliGenPythia::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
37AliGenPythia::~AliGenPythia()
38{
39}
40
41void 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();
fe4da5cc 50 fPythia->SetCKIN(3,fPtHardMin);
51 fPythia->SetCKIN(4,fPtHardMax);
52 fPythia->ProcInit(fProcess,fEnergyCMS,fStrucFunc);
5be1fe76 53 fPythia->ForceDecay(fForceDecay);
fe4da5cc 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;
5be1fe76 89 case mb:
90 break;
fe4da5cc 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:
5be1fe76 105 case pitomu:
106 case katomu:
fe4da5cc 107 fChildSelect[0]=13;
108 break;
109 }
110}
111
112void AliGenPythia::Generate()
113{
fe4da5cc 114
5be1fe76 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;
fe4da5cc 122
123
124//
fe4da5cc 125 Int_t nt=0;
5be1fe76 126 Int_t nt_p=0;
fe4da5cc 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) {
cfce8870 133 gMC->Rndm(random,6);
fe4da5cc 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 }
fe4da5cc 145 while(1)
146 {
147 fPythia->PyEvnt();
148 fTrials++;
1578254f 149 TObjArray* particles = fPythia->ImportParticles();
fe4da5cc 150 Int_t np = particles->GetEntriesFast();
151 printf("\n **************************************************%d\n",np);
152 Int_t nc=0;
153 if (np == 0 ) continue;
5be1fe76 154 if (fProcess != mb) {
155 for (Int_t i = 0; i<np; i++) {
1578254f 156 TParticle * iparticle = (TParticle *) particles->At(i);
157 Int_t kf = iparticle->GetPdgCode();
5be1fe76 158 fChildWeight=(fPythia->GetBraPart(kf))*fParentWeight;
fe4da5cc 159//
160// Parent
5be1fe76 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++;
fe4da5cc 182//
183// store parent track information
1578254f 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;
fe4da5cc 190
1578254f 191 Int_t ifch=iparticle->GetFirstDaughter();
192 Int_t ilch=iparticle->GetLastDaughter();
5be1fe76 193 if (ifch !=0 && ilch !=0) {
1578254f 194 gAlice->SetTrack(0,nt_p,kf,
5be1fe76 195 p,origin,polar,
196 0,"Primary",nt,fParentWeight);
197 gAlice->KeepTrack(nt);
198 Int_t iparent = nt;
fe4da5cc 199//
200// Children
201
5be1fe76 202 for (Int_t j=ifch; j<=ilch; j++)
203 {
1578254f 204 TParticle * ichild =
205 (TParticle *) particles->At(j-1);
206 Int_t kf = ichild->GetPdgCode();
fe4da5cc 207//
208//
5be1fe76 209 if (ChildSelected(TMath::Abs(kf))) {
1578254f 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,
5be1fe76 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++) {
1578254f 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)) {
5be1fe76 233 nc++;
234//
235// store track information
1578254f 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,
5be1fe76 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 ?
fe4da5cc 250 if (nc > 0) {
5be1fe76 251 jev+=nc;
fe4da5cc 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
265Bool_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
274Bool_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
1578254f 283Bool_t AliGenPythia::KinematicSelection(TParticle *particle)
fe4da5cc 284{
1578254f 285 Float_t px=particle->Px();
286 Float_t py=particle->Py();
287 Float_t pz=particle->Pz();
288 Float_t e=particle->Energy();
fe4da5cc 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
5be1fe76 309 Float_t theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(pz)));
fe4da5cc 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}
336void AliGenPythia::AdjustWeights()
337{
338 TClonesArray *PartArray = gAlice->Particles();
1578254f 339 TParticle *Part;
fe4da5cc 340 Int_t ntrack=gAlice->GetNtrack();
341 for (Int_t i=0; i<ntrack; i++) {
1578254f 342 Part= (TParticle*) PartArray->UncheckedAt(i);
343 Part->SetWeight(Part->GetWeight()*fKineBias);
fe4da5cc 344 }
345}
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