PYTHIA8/AliTPythia8.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  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
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  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 // Author: Andreas Morsch   27/10/2007
  17 ////////////////////////////////////////////////////////////////////////////////
  18 //                                                                            //
  19 // TPythia8                                                                   //
  20 //                                                                            //
  21 // TPythia is an interface class to C++ version of Pythia 8.1                 //
  22 // event generators, written by T.Sjostrand.                                  //
  23 //                                                                            //
  24 // The user is assumed to be familiar with the Pythia package.                //
  25 // This class includes only a basic interface to Pythia8. Because Pythia8 is  //
  26 // also written in C++, its functions/classes can be called directly from a   //
  27 // compiled C++ script.                                                       //
  28 // To call Pythia functions not available in this interface a dictionary must //
  29 // be generated.                                                              //
  30 // see $ROOTSYS/tutorials/pythia/pythia8.C for an example of use from CINT.   //
  31 //                                                                            //
  32 ////////////////////////////////////////////////////////////////////////////////
  33 /*
  34 *------------------------------------------------------------------------------------*
  35  |                                                                                    |
  36  |  *------------------------------------------------------------------------------*  |
  37  |  |                                                                              |  |
  38  |  |                                                                              |  |
  39  |  |   PPP   Y   Y  TTTTT  H   H  III    A      Welcome to the Lund Monte Carlo!  |  |
  40  |  |   P  P   Y Y     T    H   H   I    A A     This is PYTHIA version 8.100      |  |
  41  |  |   PPP     Y      T    HHHHH   I   AAAAA    Last date of change: 20 Oct 2007  |  |
  42  |  |   P       Y      T    H   H   I   A   A                                      |  |
  43  |  |   P       Y      T    H   H  III  A   A    Now is 27 Oct 2007 at 18:26:53    |  |
  44  |  |                                                                              |  |
  45  |  |   Main author: Torbjorn Sjostrand; CERN/PH, CH-1211 Geneva, Switzerland,     |  |
  46  |  |     and Department of Theoretical Physics, Lund University, Lund, Sweden;    |  |
  47  |  |     phone: + 41 - 22 - 767 82 27; e-mail: torbjorn@thep.lu.se                |  |
  48  |  |   Author: Stephen Mrenna; Computing Division, Simulations Group,             |  |
  49  |  |     Fermi National Accelerator Laboratory, MS 234, Batavia, IL 60510, USA;   |  |
  50  |  |     phone: + 1 - 630 - 840 - 2556; e-mail: mrenna@fnal.gov                   |  |
  51  |  |   Author: Peter Skands; CERN/PH, CH-1211 Geneva, Switzerland,                |  |
  52  |  |     and Theoretical Physics Department,                                      |  |
  53  |  |     Fermi National Accelerator Laboratory, MS 106, Batavia, IL 60510, USA;   |  |
  54  |  |     phone: + 41 - 22 - 767 24 59; e-mail: skands@fnal.gov                    |  |
  55  |  |                                                                              |  |
  56  |  |   The main program reference is the 'Brief Introduction to PYTHIA 8.1',      |  |
  57  |  |   T. Sjostrand, S. Mrenna and P. Skands, arXiv:0710.3820                     |  |
  58  |  |                                                                              |  |
  59  |  |   The main physics reference is the 'PYTHIA 6.4 Physics and Manual',         |  |
  60  |  |   T. Sjostrand, S. Mrenna and P. Skands, JHEP05 (2006) 026 [hep-ph/0603175]. |  |
  61  |  |                                                                              |  |
  62  |  |   An archive of program versions and documentation is found on the web:      |  |
  63  |  |   http://www.thep.lu.se/~torbjorn/Pythia.html                                |  |
  64  |  |                                                                              |  |
  65  |  |   This program is released under the GNU General Public Licence version 2.   |  |
  66  |  |   Please respect the MCnet Guidelines for Event Generator Authors and Users. |  |
  67  |  |                                                                              |  |
  68  |  |   Disclaimer: this program comes without any guarantees.                     |  |
  69  |  |   Beware of errors and use common sense when interpreting results.           |  |
  70  |  |                                                                              |  |
  71  |  |   Copyright (C) 2007 Torbjorn Sjostrand                                      |  |
  72  |  |                                                                              |  |
  73  |  |                                                                              |  |
  74  |  *------------------------------------------------------------------------------*  |
  75  |                                                                                    |
  76  *------------------------------------------------------------------------------------*
  77 */
  78
  79 #include "AliTPythia8.h"
  80
  81 #include "TClonesArray.h"
  82 #include "TParticle.h"
  83 #include "TDatabasePDG.h"
  84 #include "TLorentzVector.h"
  85
  86 ClassImp(AliTPythia8)
  87
  88 AliTPythia8*  AliTPythia8::fgInstance = 0;
  89
  90 //___________________________________________________________________________
  91 AliTPythia8::AliTPythia8():
  92     TGenerator("AliTPythia8", "AliTPythia8"),
  93     fPythia(0),
  94     fNumberOfParticles(0)
  95 {
  96    // Constructor
  97    if (fgInstance)
  98       Fatal("AliTPythia8", "There's already an instance of AliTPythia8");
  99
 100    delete fParticles; // was allocated as TObjArray in TGenerator
 101
 102    fParticles = new TClonesArray("TParticle",50);
 103    fPythia    = new Pythia8::Pythia();
 104 }
 105
 106 //___________________________________________________________________________
 107 AliTPythia8::AliTPythia8(const char *xmlDir):
 108     TGenerator("AliTPythia8", "AliTPythia8"),
 109     fPythia(0),
 110     fNumberOfParticles(0)
 111 {
 112    // Constructor with an xmlDir (eg "../xmldoc"
 113    if (fgInstance)
 114       Fatal("AliTPythia8", "There's already an instance of AliTPythia8");
 115
 116    delete fParticles; // was allocated as TObjArray in TGenerator
 117
 118    fParticles = new TClonesArray("TParticle",50);
 119    fPythia    = new Pythia8::Pythia(xmlDir);
 120 }
 121
 122 //___________________________________________________________________________
 123 AliTPythia8::~AliTPythia8()
 124 {
 125    // Destructor
 126    if (fParticles) {
 127       fParticles->Delete();
 128       delete fParticles;
 129       fParticles = 0;
 130    }
 131    delete fPythia;
 132 }
 133
 134 //___________________________________________________________________________
 135 AliTPythia8* AliTPythia8::Instance()
 136 {
 137    // Return an instance of AliTPythia8
 138    return fgInstance ? fgInstance : (fgInstance = new AliTPythia8()) ;
 139 }
 140
 141 //___________________________________________________________________________
 142 Bool_t AliTPythia8::Initialize(Int_t idAin, Int_t idBin, Double_t ecms)
 143 {
 144    // Initialization
 145    AddParticlesToPdgDataBase();
 146    return fPythia->init(idAin, idBin, ecms);
 147 }
 148
 149 //___________________________________________________________________________
 150 void AliTPythia8::GenerateEvent()
 151 {
 152    // Generate the next event
 153    fPythia->next();
 154    fNumberOfParticles  = fPythia->event.size() - 1;
 155    ImportParticles();
 156 }
 157
 158 //___________________________________________________________________________
 159 Int_t AliTPythia8::ImportParticles(TClonesArray *particles, Option_t *option)
 160 {
 161    // Import particles from Pythia stack
 162    if (particles == 0) return 0;
 163    TClonesArray &clonesParticles = *particles;
 164    clonesParticles.Clear();
 165    Int_t nparts=0;
 166    Int_t i;
 167    Int_t ioff = 0;
 168    fNumberOfParticles  = fPythia->event.size();
 169    if (fPythia->event[0].id() == 90) {
 170      ioff = -1;
 171    }
 172
 173    if (!strcmp(option,"") || !strcmp(option,"Final")) {
 174       for (i = 0; i < fNumberOfParticles; i++) {
 175         if (fPythia->event[i].id() == 90) continue;
 176          if (fPythia->event[i].isFinal()) {
 177             new(clonesParticles[nparts]) TParticle(
 178                 fPythia->event[i].id(),
 179                 fPythia->event[i].isFinal(),
 180                 fPythia->event[i].mother1() + ioff,
 181                 fPythia->event[i].mother2() + ioff,
 182                 fPythia->event[i].daughter1() + ioff,
 183                 fPythia->event[i].daughter2() + ioff,
 184                 fPythia->event[i].px(),     // [GeV/c]
 185                 fPythia->event[i].py(),     // [GeV/c]
 186                 fPythia->event[i].pz(),     // [GeV/c]
 187                 fPythia->event[i].e(),      // [GeV]
 188                 fPythia->event[i].xProd(),  // [mm]
 189                 fPythia->event[i].yProd(),  // [mm]
 190                 fPythia->event[i].zProd(),  // [mm]
 191                 fPythia->event[i].tProd()); // [mm/c]
 192                 nparts++;
 193             } // final state partice
 194         } // particle loop
 195     } else if (!strcmp(option,"All")) {
 196         for (i = 0; i < fNumberOfParticles; i++) {
 197           if (fPythia->event[i].id() == 90) continue;
 198             new(clonesParticles[nparts]) TParticle(
 199                 fPythia->event[i].id(),
 200                 fPythia->event[i].isFinal(),
 201                 fPythia->event[i].mother1() + ioff,
 202                 fPythia->event[i].mother2() + ioff,
 203                 fPythia->event[i].daughter1() + ioff,
 204                 fPythia->event[i].daughter2() + ioff,
 205                 fPythia->event[i].px(),       // [GeV/c]
 206                 fPythia->event[i].py(),       // [GeV/c]
 207                 fPythia->event[i].pz(),       // [GeV/c]
 208                 fPythia->event[i].e(),        // [GeV]
 209                 fPythia->event[i].xProd(),    // [mm]
 210                 fPythia->event[i].yProd(),    // [mm]
 211                 fPythia->event[i].zProd(),    // [mm]
 212                 fPythia->event[i].tProd());   // [mm/c]
 213                 nparts++;
 214         } // particle loop
 215     }
 216     if(ioff==-1)     fNumberOfParticles--;
 217     return nparts;
 218 }
 219
 220 //___________________________________________________________________________
 221 TObjArray* AliTPythia8::ImportParticles(Option_t* /* option */)
 222 {
 223    // Import particles from Pythia stack
 224    fParticles->Clear();
 225    Int_t nparts = 0;
 226    Int_t ioff = 0;
 227    fNumberOfParticles  = fPythia->event.size();
 228    if (fPythia->event[0].id() == 90) {
 229      ioff = -1;
 230    }
 231
 232
 233    TClonesArray &a = *((TClonesArray*)fParticles);
 234    for (Int_t i = 0; i < fNumberOfParticles; i++) {
 235      if (fPythia->event[i].id() == 90) continue;
 236       new(a[nparts]) TParticle(
 237          fPythia->event[i].id(),
 238          fPythia->event[i].isFinal(),
 239          fPythia->event[i].mother1()   + ioff,
 240          fPythia->event[i].mother2()   + ioff,
 241          fPythia->event[i].daughter1() + ioff,
 242          fPythia->event[i].daughter2() + ioff,
 243          fPythia->event[i].px(),       // [GeV/c]
 244          fPythia->event[i].py(),       // [GeV/c]
 245          fPythia->event[i].pz(),       // [GeV/c]
 246          fPythia->event[i].e(),        // [GeV]
 247          fPythia->event[i].xProd(),    // [mm]
 248          fPythia->event[i].yProd(),    // [mm]
 249          fPythia->event[i].zProd(),    // [mm]
 250          fPythia->event[i].tProd());   // [mm/c]
 251       nparts++;
 252    }
 253    if (ioff == -1) fNumberOfParticles--;
 254    return fParticles;
 255 }
 256
 257 //___________________________________________________________________________
 258 Int_t AliTPythia8::GetN() const
 259 {
 260    // Initialization
 261    return (fPythia->event.size() - 1);
 262 }
 263
 264 //___________________________________________________________________________
 265 void AliTPythia8::ReadString(const char* string) const
 266 {
 267    // Configuration
 268    fPythia->readString(string);
 269 }
 270
 271 //___________________________________________________________________________
 272 void  AliTPythia8::ReadConfigFile(const char* string) const
 273 {
 274   // Configuration
 275   fPythia->readFile(string);
 276 }
 277
 278 //___________________________________________________________________________
 279 void AliTPythia8::PrintStatistics() const
 280 {
 281    // Print end of run statistics
 282    fPythia->statistics();
 283 }
 284
 285 //___________________________________________________________________________
 286 void AliTPythia8::EventListing() const
 287 {
 288    // Event listing
 289    fPythia->event.list();
 290 }
 291
 292 //___________________________________________________________________________
 293 void AliTPythia8::AddParticlesToPdgDataBase() const
 294 {
 295    // Add some pythia specific particle code to the data base
 296
 297    TDatabasePDG *pdgDB = TDatabasePDG::Instance();
 298    pdgDB->AddParticle("string","string", 0, kTRUE,
 299                       0, 0, "QCD string", 90);
 300    pdgDB->AddParticle("rho_diff0", "rho_diff0", 0, kTRUE,
 301                       0, 0, "QCD diffr. state", 9900110);
 302    pdgDB->AddParticle("pi_diffr+", "pi_diffr+", 0, kTRUE,
 303                       0, 1, "QCD diffr. state", 9900210);
 304    pdgDB->AddParticle("omega_di", "omega_di", 0, kTRUE,
 305                       0, 0, "QCD diffr. state", 9900220);
 306    pdgDB->AddParticle("phi_diff","phi_diff", 0, kTRUE,
 307                       0, 0, "QCD diffr. state", 9900330);
 308    pdgDB->AddParticle("J/psi_di", "J/psi_di", 0, kTRUE,
 309                       0, 0, "QCD diffr. state", 9900440);
 310    pdgDB->AddParticle("n_diffr0","n_diffr0",0,kTRUE,
 311                       0, 0, "QCD diffr. state", 9902110);
 312    pdgDB->AddParticle("p_diffr+","p_diffr+", 0, kTRUE,
 313                       0, 1, "QCD diffr. state", 9902210);
 314 }
 315