/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_5_3_13_patch3/src/GeneratorInterface/LHEInterface/src/BranchingRatios.cc

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#include <map>

#include <boost/shared_ptr.hpp>

#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include "GeneratorInterface/LHEInterface/interface/LHEEvent.h"
#include "GeneratorInterface/LHEInterface/interface/Hadronisation.h"
#include "GeneratorInterface/LHEInterface/interface/BranchingRatios.h"

namespace lhef {

void BranchingRatios::reset()
{
        cache.clear();
}

void BranchingRatios::set(int pdgId, bool both, double value)
{
        cache[pdgId] = value;
        if (both)
                cache[-pdgId] = value;
}

double BranchingRatios::getFactor(
                        const Hadronisation *hadronisation,
                        const boost::shared_ptr<LHEEvent> &event) const
{
        double factor = 1.0;
        const HEPEUP *hepeup = event->getHEPEUP();
        for(int i = 0; i < hepeup->NUP; i++) {
                if (hepeup->ISTUP[i] == 1)
                        factor *= get(hepeup->IDUP[i], hadronisation);
        }
        return factor;
}

double BranchingRatios::get(int pdgId,
                            const Hadronisation *hadronisation) const
{
        std::map<int, double>::const_iterator pos = cache.find(pdgId);
        if (pos == cache.end()) {
                double val = hadronisation->totalBranchingRatio(pdgId);
                if (val <= 0.0)
                        val = 1.0;
                if (val < 0.99)
                        edm::LogInfo("Generator|LHEInterface")
                                << "Particle with pdgId " << pdgId
                                << " only partly decayed in hadronizer, "
                                   "reducing respective event cross-section "
                                   "contribution with a factor of "
                                << val << "." << std::endl;

                cache.insert(std::make_pair(pdgId, val));
                return val;
        } else
                return pos->second;
}

} // namespace lhef