AliGenCocktail.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

// Container class for AliGenerator through recursion.
// Container is itself an AliGenerator.
// What is stored are not the pointers to the generators directly but to objects of type
// AliGenCocktail entry.
// The class provides also iterator functionality.
// Author: andreas.morsch@cern.ch
//

#include <TList.h>
#include <TObjArray.h>
#include <TFormula.h>

#include "AliGenCocktail.h"
#include "AliGenCocktailEntry.h"
#include "AliCollisionGeometry.h"
#include "AliRun.h"
#include "AliLog.h"
#include "AliMC.h"
#include "AliHeader.h"
#include "AliVertexGenFile.h"
#include "AliGenCocktailEventHeader.h"
#include "AliGenHijingEventHeader.h"
#include "AliGenDPMjetEventHeader.h"

ClassImp(AliGenCocktail)

AliGenCocktail::AliGenCocktail()
  :AliGenerator(),
  fNGenerators(0),
  fTotalRate(0.),
  fSRandom(kFALSE),
  fUseSingleInjectionPerEvent(kFALSE),
  fUsePerEventRate(kFALSE),
  fProb(0),
  fEntries(0),
  flnk1(0),
  flnk2(0),
  fHeader(0),
  fSeed(0)
{
  // Constructor
  fName = "Cocktail";
  fTitle= "Particle Generator using cocktail of generators";
}

AliGenCocktail::~AliGenCocktail()
{
  // Destructor
  delete fEntries;
  fEntries = 0;
  //    delete fHeader; // It is removed in AliRunLoader
  fHeader = 0;
}

void AliGenCocktail::
AddGenerator(AliGenerator *Generator, const char* Name, Float_t RateExp, TFormula* formula, Int_t ntimes)
{
  //
  // Add a generator to the list
  // First check that list exists
  if (!fEntries) fEntries = new TList();
  fTotalRate += RateExp;
  //
  //  Forward parameters to the new generator
  if(TestBit(kPtRange) && !(Generator->TestBit(kPtRange)) && !(Generator->TestBit(kMomentumRange)))
    Generator->SetPtRange(fPtMin,fPtMax);
  if(TestBit(kMomentumRange) && !(Generator->TestBit(kPtRange)) && !(Generator->TestBit(kMomentumRange)))
    Generator->SetMomentumRange(fPMin,fPMax);

  if (TestBit(kYRange) && !(Generator->TestBit(kYRange)))
    Generator->SetYRange(fYMin,fYMax);
  if (TestBit(kPhiRange) && !(Generator->TestBit(kPhiRange)))
    Generator->SetPhiRange(fPhiMin*180/TMath::Pi(),fPhiMax*180/TMath::Pi());
  if (TestBit(kThetaRange) && !(Generator->TestBit(kThetaRange)) && !(Generator->TestBit(kEtaRange)))
    Generator->SetThetaRange(fThetaMin*180/TMath::Pi(),fThetaMax*180/TMath::Pi());
  if (!(Generator->TestBit(kVertexRange))) {
    Generator->SetOrigin(fOrigin[0], fOrigin[1], fOrigin[2]);
    Generator->SetSigma(fOsigma[0], fOsigma[1], fOsigma[2]);
    Generator->SetVertexSmear(fVertexSmear);
    Generator->SetVertexSource(kContainer);
  }
  Generator->SetTrackingFlag(fTrackIt);
  Generator->SetContainer(this);


  //
  //  Add generator to list
  char theName[256];
  snprintf(theName, 256, "%s_%d",Name, fNGenerators);
  Generator->SetName(theName);

  AliGenCocktailEntry *entry =
    new AliGenCocktailEntry(Generator, Name, RateExp);
  if (formula) entry->SetFormula(formula);
  entry->SetNTimes(ntimes);
  fEntries->Add(entry);
  fNGenerators++;
  flnk1 = 0;
  flnk2 = 0;
  fSRandom  = kFALSE;
  fHeader  = 0;
}

void AliGenCocktail::Init()
{
  // Initialisation
  TIter next(fEntries);
  AliGenCocktailEntry *entry;
  //
  // Loop over generators and initialize
  while((entry = (AliGenCocktailEntry*)next())) {
    if (fStack)  entry->Generator()->SetStack(fStack);
    if (fSeed)   entry->Generator()->SetSeed(fSeed);
    entry->Generator()->Init();
  }

  next.Reset();

  if (fSRandom) {
    fProb.Set(fNGenerators);
    next.Reset();
    Float_t sum = 0.;
    while((entry = (AliGenCocktailEntry*)next())) {
      sum += entry->Rate();
    }

    next.Reset();
    Int_t i = 0;
    Float_t psum = 0.;
    while((entry = (AliGenCocktailEntry*)next())) {
      psum +=  entry->Rate() / sum;
      fProb[i++] = psum;
    }
  }
  next.Reset();
}

void AliGenCocktail::FinishRun()
{
  // Initialisation
  TIter next(fEntries);
  AliGenCocktailEntry *entry;
  //
  // Loop over generators and initialize
  while((entry = (AliGenCocktailEntry*)next())) {
    entry->Generator()->FinishRun();
  }
}

void AliGenCocktail::Generate()
{
  //
  // Generate event
  TIter next(fEntries);
  AliGenCocktailEntry *entry = 0;
  AliGenCocktailEntry *preventry = 0;
  AliGenCocktailEntry *collentry = 0;
  AliGenerator* gen = 0;
  if (fHeader) delete fHeader;


  fHeader = new AliGenCocktailEventHeader("Cocktail Header");

  const TObjArray *partArray = gAlice->GetMCApp()->Particles();

  //
  //  Generate the vertex position used by all generators
  //
  if(fVertexSmear == kPerEvent) Vertex();

  TArrayF eventVertex;
  eventVertex.Set(3);
  for (Int_t j=0; j < 3; j++) eventVertex[j] = fVertex[j];

  if (!fSRandom) {
    //
    // Loop over generators and generate events
    Int_t igen = 0;
    int inj_gen = fUseSingleInjectionPerEvent ? TMath::Floor(gRandom->Uniform(1,fNGenerators)) : 0;
    while((entry = (AliGenCocktailEntry*)next())) {
      Int_t ntimes = entry->NTimes();
      if (fUsePerEventRate && (gRandom->Rndm() > entry->Rate())) continue;
      igen++;
      if (igen==1) {
        entry->SetFirst(0);
      } else {
        if (fUseSingleInjectionPerEvent && igen != inj_gen + 1) continue;
        entry->SetFirst((partArray->GetEntriesFast())+1);
      }

      gen = entry->Generator();
      if (gen->ProvidesCollisionGeometry()) collentry = entry;
      //
      //      Handle case in which current generator needs collision geometry from previous generator
      //
      if (gen->NeedsCollisionGeometry() && (entry->Formula() == 0))
      {
        if (preventry && preventry->Generator()->ProvidesCollisionGeometry())
        {
          gen->SetCollisionGeometry(preventry->Generator()->CollisionGeometry());
        } else {
          Fatal("Generate()", "No Collision Geometry Provided");
        }
      }
      //
      //      Number of signals is calculated from Collision Geometry
      //      and entry with given centrality bin is selected
      //
      if (entry->Formula() != 0)
      {
        AliCollisionGeometry* coll = NULL;
	
	if (!collentry) {
	  const AliVertexGenFile* vtxGen =  (AliVertexGenFile*)gAlice->GetMCApp()->Generator()->GetVertexGenerator();
	  if(vtxGen){
	    const AliHeader* hBg = vtxGen->GetHeader();
	    if (hBg) {
	      AliGenEventHeader* genHeader = hBg->GenEventHeader();
	      coll = dynamic_cast<AliCollisionGeometry*>(genHeader);
	      if (!coll) {
		AliFatalF("Header %s does not provide collision geometry",genHeader->IsA()->GetName());
	      }
	    }
	  }
	}
	else{
	  coll = (collentry->Generator())->CollisionGeometry();
	}
	
	if (!coll) {
          Fatal("Generate()", "No Collision Geometry Provided");
          return;
        }
	
        Float_t b  = coll->ImpactParameter();
        Int_t nsig = Int_t(entry->Formula()->Eval(b));
        Int_t bin = entry->Bin() - 100;
        if (bin > 0) {
          if (bin != nsig) continue;
        } else {
          if (nsig < 1) nsig = 1;
          AliInfo(Form("Signal Events %13.3f %5d %5d\n", b, coll->HardScatters(), nsig));
          ntimes = nsig;
        }
      }
      AliInfo(Form("Generator %d: %s; ntimes=%d; Vertex (%f,%f,%f) cm   Time %f ns",
		   igen,gen->ClassName(),ntimes,fVertex.At(0), fVertex.At(1), fVertex.At(2), fTime*1e9));
      gen->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2), fTime);

      gen->GenerateN(ntimes);
      entry->SetLast(partArray->GetEntriesFast());
      preventry = entry;
    }
  } else if (fSRandom) {
    //
    // Select a generator randomly
    //
    Int_t i;
    Float_t p0 =  gRandom->Rndm();

    for (i = 0; i < fNGenerators; i++) {
      if (p0 < fProb[i]) break;
    }

    entry = (AliGenCocktailEntry*) fEntries->At(i);
    entry->SetFirst(0);
    gen = entry->Generator();
    gen->SetVertex(fVertex.At(0), fVertex.At(1), fVertex.At(2), fTime);
    gen->Generate();
    entry->SetLast(partArray->GetEntriesFast());
  }

  next.Reset();

  // Event Vertex
  fHeader->SetPrimaryVertex(eventVertex);
  fHeader->SetInteractionTime(fTime);
  fHeader->CalcNProduced();
  if (fContainer) {
    fHeader->SetName(fName);
    fContainer->AddHeader(fHeader);
  } else {
    gAlice->SetGenEventHeader(fHeader);
  }
}

void AliGenCocktail::SetVertexSmear(VertexSmear_t smear)
{
  // Set vertex smearing and propagate it to the generators

  AliGenerator::SetVertexSmear(smear);
  TIter next(fEntries);
  while (AliGenCocktailEntry* entry = (AliGenCocktailEntry*)next()) {
    entry->Generator()->SetVertexSmear(smear);
  }
}

AliGenCocktailEntry *  AliGenCocktail::FirstGenerator()
{
  // Iterator over generators: Initialisation
  flnk1 = fEntries->FirstLink();
  if (flnk1) {
    return (AliGenCocktailEntry*) (flnk1->GetObject());
  } else {
    return 0;
  }
}

AliGenCocktailEntry*  AliGenCocktail::NextGenerator()
{
  // Iterator over generators: Increment
  flnk1 = flnk1->Next();
  if (flnk1) {
    return (AliGenCocktailEntry*) (flnk1->GetObject());
  } else {
    return 0;
  }
}

void AliGenCocktail::
FirstGeneratorPair(AliGenCocktailEntry*& e1, AliGenCocktailEntry*& e2)
{
  // Iterator over generator pairs: Initialisation
  flnk2 = flnk1 = fEntries->FirstLink();
  if (flnk1) {
    e2 = e1 = (AliGenCocktailEntry*) (flnk1->GetObject());
  } else {
    e2= e1 = 0;
  }
}

void AliGenCocktail::
NextGeneratorPair(AliGenCocktailEntry*& e1, AliGenCocktailEntry*& e2)
{
  // Iterator over generators: Increment
  flnk2 = flnk2->Next();
  if (flnk2) {
    e1 = (AliGenCocktailEntry*) (flnk1->GetObject());
    e2 = (AliGenCocktailEntry*) (flnk2->GetObject());
  } else {
    flnk2 = flnk1 = flnk1->Next();
    if (flnk1) {
      e1 = (AliGenCocktailEntry*) (flnk1->GetObject());
      e2 = (AliGenCocktailEntry*) (flnk2->GetObject());
    } else {
      e1=0;
      e2=0;
    }
  }
}

void AliGenCocktail::AddHeader(AliGenEventHeader* header)
{
  // Add a header to the list
  if (fHeader) fHeader->AddHeader(header);
}