Unique names for functions enforced.
[u/mrichter/AliRoot.git] / EVGEN / AliGenParam.cxx
1 /**************************************************************************
2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3  *                                                                        *
4  * Author: The ALICE Off-line Project.                                    *
5  * Contributors are mentioned in the code where appropriate.              *
6  *                                                                        *
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8  * documentation strictly for non-commercial purposes is hereby granted   *
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10  * copies and that both the copyright notice and this permission notice   *
11  * appear in the supporting documentation. The authors make no claims     *
12  * about the suitability of this software for any purpose. It is          *
13  * provided "as is" without express or implied warranty.                  *
14  **************************************************************************/
15
16 /* $Id$ */
17
18 // Class to generate particles from using paramtrized pT and y distributions.
19 // Distributions are obtained from pointer to object of type AliGenLib.
20 // (For example AliGenMUONlib)
21 // Decays are performed using Pythia.
22 // andreas.morsch@cern.ch
23
24 #include "AliGenParam.h"
25 #include "AliDecayer.h"
26 #include "AliGenMUONlib.h"
27 #include "AliRun.h"
28 #include <TParticle.h>
29 #include <TParticlePDG.h>
30 #include <TDatabasePDG.h>
31 #include <TLorentzVector.h>
32 #include <TVirtualMC.h>
33
34 #include <TF1.h>
35 #include <TCanvas.h>
36 #include <TH1.h>
37 #include "AliMC.h"
38
39 ClassImp(AliGenParam)
40
41 //------------------------------------------------------------
42
43   //Begin_Html
44   /*
45     <img src="picts/AliGenParam.gif">
46   */
47   //End_Html
48
49 //____________________________________________________________
50 //____________________________________________________________
51 AliGenParam::AliGenParam()
52 {
53 // Deafault constructor
54     fPtPara = 0;
55     fYPara  = 0;
56     fParam  = 0;
57     fAnalog = kAnalog;
58     SetDeltaPt();
59     fDecayer = 0;
60
61
62 }
63
64 AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Int_t param, char* tname):AliGenMC(npart)
65 {
66 // Constructor using number of particles parameterisation id and library
67     fName = "Param";
68     fTitle= "Particle Generator using pT and y parameterisation";
69     
70     fPtParaFunc = Library->GetPt(param, tname);
71     fYParaFunc  = Library->GetY (param, tname);
72     fIpParaFunc = Library->GetIp(param, tname);
73     
74     fPtPara = 0;
75     fYPara  = 0;
76     fParam  = param;
77     fAnalog = kAnalog;
78     SetForceDecay();
79     SetDeltaPt(); 
80 }
81
82 //____________________________________________________________
83
84 AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(npart)
85 {
86 // Constructor using parameterisation id and number of particles
87 //
88     fName = "Param";
89     fTitle= "Particle Generator using pT and y parameterisation";
90       
91     AliGenLib* pLibrary = new AliGenMUONlib();
92  
93     fPtParaFunc = pLibrary->GetPt(param, tname);
94     fYParaFunc  = pLibrary->GetY (param, tname);
95     fIpParaFunc = pLibrary->GetIp(param, tname);
96     
97     fPtPara = 0;
98     fYPara  = 0;
99     fParam  = param;
100     fAnalog = kAnalog;
101     fChildSelect.Set(5);
102     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
103     SetForceDecay();
104     SetCutOnChild();
105     SetChildMomentumRange();
106     SetChildPtRange();
107     SetChildPhiRange();
108     SetChildThetaRange(); 
109     SetDeltaPt(); 
110 }
111
112 AliGenParam::AliGenParam(Int_t npart, Int_t param,
113                          Double_t (*PtPara) (Double_t*, Double_t*),
114                          Double_t (*YPara ) (Double_t* ,Double_t*),
115                          Int_t    (*IpPara) (TRandom *))                 
116     :AliGenMC(npart)
117 {
118 // Constructor
119 // Gines Martinez 1/10/99 
120     fName = "Param";
121     fTitle= "Particle Generator using pT and y parameterisation";
122
123     fPtParaFunc = PtPara; 
124     fYParaFunc  = YPara;  
125     fIpParaFunc = IpPara;
126 //  
127     fPtPara = 0;
128     fYPara  = 0;
129     fParam  = param;
130     fAnalog = kAnalog;
131     fChildSelect.Set(5);
132     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
133     SetForceDecay();
134     SetCutOnChild();
135     SetChildMomentumRange();
136     SetChildPtRange();
137     SetChildPhiRange();
138     SetChildThetaRange();  
139     SetDeltaPt();
140 }
141
142
143 AliGenParam::AliGenParam(const AliGenParam & Param)
144     :AliGenMC(Param)
145 {
146 // Copy constructor
147     Param.Copy(*this);
148 }
149
150 //____________________________________________________________
151 AliGenParam::~AliGenParam()
152 {
153 // Destructor
154     delete  fPtPara;
155     delete  fYPara;
156 }
157
158 //____________________________________________________________
159 void AliGenParam::Init()
160 {
161 // Initialisation
162
163     if (gMC) fDecayer = gMC->GetDecayer();
164   //Begin_Html
165   /*
166     <img src="picts/AliGenParam.gif">
167   */
168   //End_Html
169     char name[256];
170     sprintf(name, "pt-parameterisation for %s", GetName());
171     
172     fPtPara = new TF1(name, fPtParaFunc, fPtMin, fPtMax,0);
173 //  Set representation precision to 10 MeV
174     Int_t npx= Int_t((fPtMax - fPtMin) / fDeltaPt);
175     
176     fPtPara->SetNpx(npx);
177
178     sprintf(name, "y-parameterisation  for %s", GetName());
179     fYPara  = new TF1(name, fYParaFunc, fYMin, fYMax, 0);
180     
181     sprintf(name, "pt-for-%s", GetName());
182     TF1 ptPara(name ,fPtParaFunc, 0, 15, 0);
183     sprintf(name, "y-for-%s", GetName());
184     TF1 yPara(name, fYParaFunc, -6, 6, 0);
185
186 //
187 // dN/dy| y=0
188     Double_t y1=0;
189     Double_t y2=0;
190     
191     fdNdy0=fYParaFunc(&y1,&y2);
192 //
193 // Integral over generation region
194     Float_t intYS  = yPara.Integral(fYMin, fYMax);
195     Float_t intPt0 = ptPara.Integral(0,15);
196     Float_t intPtS = ptPara.Integral(fPtMin,fPtMax);
197     Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
198     if (fAnalog == kAnalog) {
199         fYWgt  = intYS/fdNdy0;
200         fPtWgt = intPtS/intPt0;
201         fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
202     } else {
203         fYWgt = intYS/fdNdy0;
204         fPtWgt = (fPtMax-fPtMin)/intPt0;
205         fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
206     }
207 //
208 // particle decay related initialization
209     fDecayer->SetForceDecay(fForceDecay);
210     fDecayer->Init();
211
212 //
213     AliGenMC::Init();
214 }
215
216 //____________________________________________________________
217 void AliGenParam::Generate()
218 {
219 //
220 // Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
221 // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and 
222 // antineutrons in the the desired theta, phi and momentum windows; 
223 // Gaussian smearing on the vertex is done if selected. 
224 // The decay of heavy mesons is done using lujet, 
225 //    and the childern particle are tracked by GEANT
226 // However, light mesons are directly tracked by GEANT 
227 // setting fForceDecay = nodecay (SetForceDecay(nodecay)) 
228 //
229 //
230 //  Reinitialize decayer
231     fDecayer->Init();
232 //
233   Float_t polar[3]= {0,0,0};  // Polarisation of the parent particle (for GEANT tracking)
234   Float_t origin0[3];         // Origin of the generated parent particle (for GEANT tracking)
235   Float_t pt, pl, ptot;       // Transverse, logitudinal and total momenta of the parent particle
236   Float_t phi, theta;         // Phi and theta spherical angles of the parent particle momentum
237   Float_t p[3], pc[3], 
238           och[3];             // Momentum, polarisation and origin of the children particles from lujet
239   Double_t ty, xmt;
240   Int_t nt, i, j;
241   Float_t  wgtp, wgtch;
242   Double_t dummy;
243   static TClonesArray *particles;
244   //
245   if(!particles) particles = new TClonesArray("TParticle",1000);
246   
247   TDatabasePDG *pDataBase = TDatabasePDG::Instance();
248   //
249   Float_t random[6];
250  
251 // Calculating vertex position per event
252   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
253   if(fVertexSmear==kPerEvent) {
254       Vertex();
255       for (j=0;j<3;j++) origin0[j]=fVertex[j];
256   }
257   
258   Int_t ipa=0;
259   
260 // Generating fNpart particles
261   while (ipa<fNpart) {
262       while(1) {
263 //
264 // particle type
265           Int_t iPart = fIpParaFunc(fRandom);
266           fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;          
267           TParticlePDG *particle = pDataBase->GetParticle(iPart);
268           Float_t am = particle->Mass();
269           
270           Rndm(random,2);
271 //
272 // phi
273           phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
274 //
275 // y
276           ty = TMath::TanH(fYPara->GetRandom());
277 //
278 // pT
279           if (fAnalog == kAnalog) {
280               pt=fPtPara->GetRandom();
281               wgtp=fParentWeight;
282               wgtch=fChildWeight;
283           } else {
284               pt=fPtMin+random[1]*(fPtMax-fPtMin);
285               Double_t ptd=pt;
286               wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
287               wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
288           }
289           xmt=sqrt(pt*pt+am*am);
290           if (TMath::Abs(ty)==1.) {
291               ty=0.;
292               Fatal("AliGenParam", 
293                     "Division by 0: Please check you rapidity range !");
294           }
295           
296           pl=xmt*ty/sqrt(1.-ty*ty);
297           theta=TMath::ATan2(pt,pl);
298 // Cut on theta
299           if(theta<fThetaMin || theta>fThetaMax) continue;
300           ptot=TMath::Sqrt(pt*pt+pl*pl);
301 // Cut on momentum
302           if(ptot<fPMin || ptot>fPMax) continue;
303 //
304           p[0]=pt*TMath::Cos(phi);
305           p[1]=pt*TMath::Sin(phi);
306           p[2]=pl;
307           if(fVertexSmear==kPerTrack) {
308               Rndm(random,6);
309               for (j=0;j<3;j++) {
310                   origin0[j]=
311                       fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
312                       TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
313               }
314           }
315           
316 // Looking at fForceDecay : 
317 // if fForceDecay != none Primary particle decays using 
318 // AliPythia and children are tracked by GEANT
319 //
320 // if fForceDecay == none Primary particle is tracked by GEANT 
321 // (In the latest, make sure that GEANT actually does all the decays you want)    
322 //
323
324           if (fForceDecay != kNoDecay) {
325 // Using lujet to decay particle
326               Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
327               TLorentzVector pmom(p[0], p[1], p[2], energy);
328               fDecayer->Decay(iPart,&pmom);
329 //
330 // select decay particles
331               Int_t np=fDecayer->ImportParticles(particles);
332
333               //  Selecting  GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
334               if (fGeometryAcceptance) 
335                 if (!CheckAcceptanceGeometry(np,particles)) continue;
336               Int_t ncsel=0;
337               Int_t* pFlag      = new Int_t[np];
338               Int_t* pParent    = new Int_t[np];
339               Int_t* pSelected  = new Int_t[np];
340               Int_t* trackIt    = new Int_t[np];
341
342               for (i=0; i<np; i++) {
343                   pFlag[i]     =  0;
344                   pSelected[i] =  0;
345                   pParent[i]   = -1;
346               }
347               
348               if (np >1) {
349                   TParticle* iparticle =  (TParticle *) particles->At(0);
350                   Int_t ipF, ipL;
351                   for (i = 1; i<np ; i++) {
352                       trackIt[i] = 1;
353                       iparticle = (TParticle *) particles->At(i);
354                       Int_t kf = iparticle->GetPdgCode();
355                       Int_t ks = iparticle->GetStatusCode();
356 // flagged particle
357
358                       if (pFlag[i] == 1) {
359                           ipF = iparticle->GetFirstDaughter();
360                           ipL = iparticle->GetLastDaughter();   
361                           if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
362                           continue;
363                       }
364
365 // flag decay products of particles with long life-time (c tau > .3 mum)                      
366                       
367                       if (ks != 1) { 
368 //                        TParticlePDG *particle = pDataBase->GetParticle(kf);
369                           
370                           Double_t lifeTime = fDecayer->GetLifetime(kf);
371 //                        Double_t mass     = particle->Mass();
372 //                        Double_t width    = particle->Width();
373                           if (lifeTime > (Double_t) fMaxLifeTime) {
374                               ipF = iparticle->GetFirstDaughter();
375                               ipL = iparticle->GetLastDaughter();       
376                               if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
377                           } else{
378                               trackIt[i]     = 0;
379                               pSelected[i]   = 1;
380                           }
381                       } // ks==1 ?
382 //
383 // children
384                       
385                       if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll && trackIt[i])
386                       {
387                           if (fCutOnChild) {
388                               pc[0]=iparticle->Px();
389                               pc[1]=iparticle->Py();
390                               pc[2]=iparticle->Pz();
391                               Bool_t  childok = KinematicSelection(iparticle, 1);
392                               if(childok) {
393                                   pSelected[i]  = 1;
394                                   ncsel++;
395                               } else {
396                                   ncsel=-1;
397                                   break;
398                               } // child kine cuts
399                           } else {
400                               pSelected[i]  = 1;
401                               ncsel++;
402                           } // if child selection
403                       } // select muon
404                   } // decay particle loop
405               } // if decay products
406               
407               Int_t iparent;
408               if ((fCutOnChild && ncsel >0) || !fCutOnChild){
409                   ipa++;
410 //
411 // Parent
412                   PushTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp);
413                   pParent[0] = nt;
414                   KeepTrack(nt); 
415 //
416 // Decay Products
417 //                
418                   for (i = 1; i < np; i++) {
419                       if (pSelected[i]) {
420                           TParticle* iparticle = (TParticle *) particles->At(i);
421                           Int_t kf  = iparticle->GetPdgCode();
422                           Int_t ipa = iparticle->GetFirstMother()-1;
423                           
424                           och[0] = origin0[0]+iparticle->Vx()/10;
425                           och[1] = origin0[1]+iparticle->Vy()/10;
426                           och[2] = origin0[2]+iparticle->Vz()/10;
427                           pc[0]  = iparticle->Px();
428                           pc[1]  = iparticle->Py();
429                           pc[2]  = iparticle->Pz();
430                           
431                           if (ipa > -1) {
432                               iparent = pParent[ipa];
433                           } else {
434                               iparent = -1;
435                           }
436                          
437                           PushTrack(fTrackIt*trackIt[i], iparent, kf,
438                                            pc, och, polar,
439                                            0, kPDecay, nt, wgtch);
440                           pParent[i] = nt;
441                           KeepTrack(nt); 
442                       } // Selected
443                   } // Particle loop 
444               }  // Decays by Lujet
445               particles->Clear();
446               if (pFlag)      delete[] pFlag;
447               if (pParent)    delete[] pParent;
448               if (pSelected)  delete[] pSelected;          
449               if (trackIt)    delete[] trackIt;
450           } // kinematic selection
451           else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
452           {
453             gAlice->GetMCApp()->
454                 PushTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
455             ipa++; 
456           }
457           break;
458     } // while
459   } // event loop
460   SetHighWaterMark(nt);
461 }
462
463 void AliGenParam::Draw( const char * /*opt*/)
464 {
465     //
466     // Draw the pT and y Distributions
467     //
468      TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
469      c0->Divide(2,1);
470      c0->cd(1);
471      fPtPara->Draw();
472      fPtPara->GetHistogram()->SetXTitle("p_{T} (GeV)");     
473      c0->cd(2);
474      fYPara->Draw();
475      fYPara->GetHistogram()->SetXTitle("y");     
476 }
477
478 AliGenParam& AliGenParam::operator=(const  AliGenParam& rhs)
479 {
480 // Assignment operator
481     rhs.Copy(*this);
482     return *this;
483 }
484
485
486