libthepeg-dev 1.8.0-1.1 / usr / include / ThePEG / Vectors / HepMCConverter.tcc

// -*- C++ -*-
//
// HepMCConverter.tcc is a part of ThePEG - Toolkit for HEP Event Generation
// Copyright (C) 1999-2011 Leif Lonnblad
//
// ThePEG is licenced under version 2 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
//
// This is the implementation of the non-inlined, non-templated member
// functions of the HepMCConverter class.
//

#include "HepMCConverter.h"
#include "ThePEG/StandardModel/StandardModelBase.h"
#include "ThePEG/Repository/EventGenerator.h"
#include "ThePEG/EventRecord/Particle.h"
#include "ThePEG/EventRecord/StandardSelectors.h"
#include "ThePEG/EventRecord/Collision.h"
#include "ThePEG/EventRecord/Step.h"
#include "ThePEG/EventRecord/SubProcess.h"
#include "ThePEG/Handlers/XComb.h"
#include "ThePEG/Handlers/EventHandler.h"
#include "ThePEG/PDF/PartonExtractor.h"
#include "ThePEG/PDF/PDF.h"
#include "ThePEG/PDT/StandardMatchers.h"
#include "ThePEG/Utilities/Throw.h"

namespace ThePEG {


template <typename HepMCEventT, typename Traits>
typename HepMCConverter<HepMCEventT,Traits>::GenEvent *
HepMCConverter<HepMCEventT,Traits>::
convert(const Event & ev, bool nocopies, Energy eunit, Length lunit) {
  HepMCConverter<HepMCEventT,Traits> converter(ev, nocopies, eunit, lunit);
  return converter.geneve;
}

template <typename HepMCEventT, typename Traits>
void HepMCConverter<HepMCEventT,Traits>::
convert(const Event & ev, GenEvent & gev, bool nocopies) {
  HepMCConverter<HepMCEventT,Traits>
    converter(ev, gev, nocopies,
	      Traits::momentumUnit(gev), Traits::lengthUnit(gev));
}

template <typename HepMCEventT, typename Traits>
void HepMCConverter<HepMCEventT,Traits>::
convert(const Event & ev, GenEvent & gev, bool nocopies,
	Energy eunit, Length lunit) {
  HepMCConverter<HepMCEventT,Traits> converter(ev, gev, nocopies, eunit, lunit);
}

template <typename HepMCEventT, typename Traits>
HepMCConverter<HepMCEventT,Traits>::
HepMCConverter(const Event & ev, bool nocopies, Energy eunit, Length lunit)
  : energyUnit(eunit), lengthUnit(lunit) {

  geneve = Traits::newEvent(ev.number(), ev.weight(), ev.optionalWeights());

  init(ev, nocopies);

}

template <typename HepMCEventT, typename Traits>
HepMCConverter<HepMCEventT,Traits>::
HepMCConverter(const Event & ev, GenEvent & gev, bool nocopies,
	       Energy eunit, Length lunit)
  : energyUnit(eunit), lengthUnit(lunit) {

  geneve = &gev;
  Traits::resetEvent(geneve, ev.number(), ev.weight(), ev.optionalWeights());

  init(ev, nocopies);

}

struct ParticleOrderNumberCmp {
  bool operator()(tcPPtr a, tcPPtr b) const {
    return a->number() < b->number();
  }
};

template <typename HepMCEventT, typename Traits>
void HepMCConverter<HepMCEventT,Traits>::init(const Event & ev, bool nocopies) {

  if ( lengthUnit != millimeter && lengthUnit != centimeter )
    Throw<HepMCConverterException>()
      << "Length unit used for HepMC::GenEvent was not MM nor CM."
      << Exception::runerror;
  if ( energyUnit != GeV && energyUnit != MeV )
    Throw<HepMCConverterException>()
      << "Momentum unit used for HepMC::GenEvent was not GEV nor MEV."
      << Exception::runerror;
  Traits::setUnits(*geneve, energyUnit, lengthUnit);

  tcEHPtr eh;
  if ( ev.primaryCollision() && ( eh =
       dynamic_ptr_cast<tcEHPtr>(ev.primaryCollision()->handler()) ) ) {

    // Get general event info if present.
    Traits::setScaleAndAlphas(*geneve, eh->lastScale(),
			      eh->SM().alphaS(eh->lastScale()),
			      eh->SM().alphaEM(eh->lastScale()), energyUnit);
  }

  // Extract all particles and order them.
  tcPVector all;
  ev.select(back_inserter(all), SelectAll());
  stable_sort(all.begin(), all.end(), ParticleOrderNumberCmp());
  vertices.reserve(all.size()*2);

  // Create GenParticle's and map them to the ThePEG particles.
  for ( int i = 0, N = all.size(); i < N; ++i ) {
    tcPPtr p = all[i];
    if ( nocopies && p->next() ) continue;
    if ( pmap.find(p) != pmap.end() ) continue;
    GenParticle * gp = pmap[p] = createParticle(p);
    if ( p->hasColourInfo() ) {
      // Check if the particle is connected to colour lines, in which
      // case the lines are mapped to an integer and set in the
      // GenParticle's Flow info.
      tcColinePtr l;
      if ( (l = p->colourLine()) ) {
	if ( !member(flowmap, l) ) flowmap[l] = flowmap.size() + 500;
	Traits::setColourLine(*gp, 1, flowmap[l]);
      }
      if ( (l = p->antiColourLine()) ) {
	if ( !member(flowmap, l) ) flowmap[l] = flowmap.size() + 500;
	Traits::setColourLine(*gp, 2, flowmap[l]);
      }
    }

    if ( !p->children().empty() || p->next() ) {
      // If the particle has children it should have a decay vertex:
      vertices.push_back(Vertex());
      decv[p] = &vertices.back();
      vertices.back().in.insert(p);
    }

    if ( !p->parents().empty() || p->previous() ||
	 (p->children().empty() && !p->next()) ) {
      // If the particle has parents it should have a production
      // vertex. If neither parents or children it should still have a
      // dummy production vertex.
      vertices.push_back(Vertex());
      prov[p] = &vertices.back();
      vertices.back().out.insert(p);
    }
  }

  // Now go through the the particles again, and join the vertices.
  for ( int i = 0, N = all.size(); i < N; ++i ) {
    tcPPtr p = all[i];
    if ( nocopies ) {
      if ( p->next() ) continue;
      for ( int i = 0, N = p->children().size(); i < N; ++i )
	join(p, p->children()[i]->final());
      tcPPtr pp = p;
      while ( pp->parents().empty() && pp->previous() ) pp = pp->previous();
      for ( int i = 0, N = pp->parents().size(); i < N; ++i )
	join(pp->parents()[i]->final(), p);
    } else {
      for ( int i = 0, N = p->children().size(); i < N; ++i )
	join(p, p->children()[i]);
      if ( p->next() ) join(p, p->next());
      for ( int i = 0, N = p->parents().size(); i < N; ++i )
	join(p->parents()[i], p);
      if ( p->previous() ) join(p->previous(), p);
    }
  }

  // Time to create the GenVertex's
  for ( typename VertexMap::iterator it = prov.begin(); it != prov.end(); ++it )
    if ( !member(vmap, it->second) )
      vmap[it->second] = createVertex(it->second);
  for ( typename VertexMap::iterator it = decv.begin(); it != decv.end(); ++it )
    if ( !member(vmap, it->second) )
      vmap[it->second] = createVertex(it->second);

  // Now find the primary signal process vertex defined to be the
  // decay vertex of the first parton coming into the primary hard
  // sub-collision.
  tSubProPtr sub = ev.primarySubProcess();
  if ( sub && sub->incoming().first ) {
    const Vertex * prim = decv[sub->incoming().first];
    Traits::setSignalProcessVertex(*geneve, vmap[prim]);
    vmap.erase(prim);
  }
  
  // Then add the rest of the vertices.
  for ( typename GenVertexMap::iterator it = vmap.begin();
	it != vmap.end(); ++it )
    Traits::addVertex(*geneve, it->second);

  // and the incoming beam particles
  Traits::setBeamParticles(*geneve,pmap[ev.incoming().first],
			   pmap[ev.incoming().second]);

  // and the PDF info
  setPdfInfo(ev);

  // and the cross section info
  Traits::setCrossSection(*geneve,
			  eh->integratedXSec()/picobarn,
			  eh->integratedXSecErr()/picobarn);

}

template <typename HepMCEventT, typename Traits>
typename HepMCConverter<HepMCEventT,Traits>::GenParticle *
HepMCConverter<HepMCEventT,Traits>::createParticle(tcPPtr p) const {
  int status = 1;
  if ( !p->children().empty() || p->next() ) status = 11;
  if ( !p->children().empty() ) {
    long id = p->data().id();
    if ( BaryonMatcher::Check(id) || MesonMatcher::Check(id) ||
	 id == ParticleID::muminus || id == ParticleID::muplus ||
	 id == ParticleID::tauminus || id == ParticleID::tauplus )
      if ( p->mass() <= p->data().massMax() &&
	   p->mass() >= p->data().massMin() ) status = 2;
  }
  GenParticle * gp =
    Traits::newParticle(p->momentum(), p->id(), status, energyUnit);

  if ( p->spinInfo() && p->spinInfo()->hasPolarization() ) {
    DPair pol = p->spinInfo()->polarization();
    Traits::setPolarization(*gp, pol.first, pol.second);
  }

  return gp;

}

template <typename HepMCEventT, typename Traits>
void HepMCConverter<HepMCEventT,Traits>::join(tcPPtr parent, tcPPtr child) {
  Vertex * dec = decv[parent];
  Vertex * pro = prov[child];
  if ( !pro || !dec ) Throw<HepMCConverterException>()
    << "Found a reference to a ThePEG::Particle which was not in the Event."
    << Exception::eventerror;
  if ( pro == dec ) return;
  while ( !pro->in.empty() ) {
    dec->in.insert(*(pro->in.begin()));
    decv[*(pro->in.begin())] = dec;
    pro->in.erase(pro->in.begin());
  }
  while ( !pro->out.empty() ) {
    dec->out.insert(*(pro->out.begin()));
    prov[*(pro->out.begin())] = dec;
    pro->out.erase(pro->out.begin());
  }
}

template <typename HepMCEventT, typename Traits>
typename HepMCConverter<HepMCEventT,Traits>::GenVertex *
HepMCConverter<HepMCEventT,Traits>::createVertex(Vertex * v) {
  if ( !v ) Throw<HepMCConverterException>()
    << "Found internal null Vertex." << Exception::abortnow;

  GenVertex * gv = new GenVertex();

  // We assume that the vertex position is the average of the decay
  // vertices of all incoming and the creation vertices of all
  // outgoing particles in the lab. Note that this will probably not
  // be useful information for very small distances.
  LorentzPoint p;
  for ( tcParticleSet::iterator it = v->in.begin();
	it != v->in.end(); ++it ) {
    p += (**it).labDecayVertex();
    Traits::addIncoming(*gv, pmap[*it]);
  }
  for ( tcParticleSet::iterator it = v->out.begin();
	it != v->out.end(); ++it ) {
    p += (**it).labVertex();
    Traits::addOutgoing(*gv, pmap[*it]);
  }

  p /= double(v->in.size() + v->out.size());
  Traits::setPosition(*gv, p, lengthUnit);

  return gv;
}

template <typename HepMCEventT, typename Traits>
void HepMCConverter<HepMCEventT,Traits>::setPdfInfo(const Event & e) {
  // ids of the partons going into the primary sub process
  tSubProPtr sub = e.primarySubProcess();
  int id1 = sub->incoming().first ->id();
  int id2 = sub->incoming().second->id();
  // get the event handler
  tcEHPtr eh = dynamic_ptr_cast<tcEHPtr>(e.handler());
  // get the values of x
  double x1 = eh->lastX1();
  double x2 = eh->lastX2();
  // get the pdfs
  pair<PDF,PDF> pdfs;
  pdfs.first  =  eh->pdf<PDF>(sub->incoming().first );
  pdfs.second =  eh->pdf<PDF>(sub->incoming().second);
  // get the scale
  Energy2 scale = eh->lastScale();
  // get the values of the pdfs
  double xf1 = pdfs.first.xfx(sub->incoming().first->dataPtr(), scale, x1);
  double xf2 = pdfs.second.xfx(sub->incoming().second->dataPtr(), scale, x2);

  Traits::setPdfInfo(*geneve, id1, id2, x1, x2, sqrt(scale/GeV2), xf1, xf2);

}



}