LHEInterface/src/LHEEvent.cc

0001 #include <algorithm>
0002 #include <iomanip>
0003 #include <iostream>
0004 #include <memory>
0005
0006 #include <cmath>
0007 #include <cstring>
0008 #include <memory>
0009 #include <sstream>
0010 #include <string>
0011 #include <vector>
0012
0013 #include "HepMC/GenEvent.h"
0014 #include "HepMC/GenVertex.h"
0015 #include "HepMC/GenParticle.h"
0016 #include "HepMC/SimpleVector.h"
0017
0018 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0019
0020 #include "SimDataFormats/GeneratorProducts/interface/LesHouches.h"
0021
0022 #include "GeneratorInterface/LHEInterface/interface/LHERunInfo.h"
0023 #include "GeneratorInterface/LHEInterface/interface/LHEEvent.h"
0024
0025 static int skipWhitespace(std::istream &in) {
0026   int ch;
0027   do {
0028     ch = in.get();
0029   } while (std::isspace(ch));
0030   if (ch != std::istream::traits_type::eof())
0031     in.putback(ch);
0032   return ch;
0033 }
0034
0035 namespace lhef {
0036
0037   LHEEvent::LHEEvent(const std::shared_ptr<LHERunInfo> &runInfo, std::istream &in)
0038       : runInfo(runInfo),
0039         weights_(0),
0040         counted(false),
0041         readAttemptCounter(0),
0042         npLO_(-99),
0043         npNLO_(-99),
0044         evtnum_(-1)
0045
0046   {
0047     hepeup.NUP = 0;
0048     hepeup.XPDWUP.first = hepeup.XPDWUP.second = 0.0;
0049
0050     in >> hepeup.NUP >> hepeup.IDPRUP >> hepeup.XWGTUP >> hepeup.SCALUP >> hepeup.AQEDUP >> hepeup.AQCDUP;
0051     if (!in.good())
0052       throw cms::Exception("InvalidFormat") << "Les Houches file contained invalid"
0053                                                " event header."
0054                                             << std::endl;
0055
0056     // store the original value of XWGTUP for the user
0057     originalXWGTUP_ = hepeup.XWGTUP;
0058
0059     int idwtup = runInfo->getHEPRUP()->IDWTUP;
0060     if (idwtup >= 0 && hepeup.XWGTUP < 0) {
0061       edm::LogWarning("Generator|LHEInterface") << "Non-allowed negative event weight encountered." << std::endl;
0062       hepeup.XWGTUP = std::abs(hepeup.XWGTUP);
0063     }
0064
0065     if (std::abs(idwtup) == 3 && std::abs(hepeup.XWGTUP) != 1.) {
0066       edm::LogInfo("Generator|LHEInterface") << "Event weight not set to one for abs(IDWTUP) == 3" << std::endl;
0067       hepeup.XWGTUP = hepeup.XWGTUP > 0. ? 1.0 : -1.0;
0068     }
0069
0070     hepeup.resize();
0071
0072     for (int i = 0; i < hepeup.NUP; i++) {
0073       in >> hepeup.IDUP[i] >> hepeup.ISTUP[i] >> hepeup.MOTHUP[i].first >> hepeup.MOTHUP[i].second >>
0074           hepeup.ICOLUP[i].first >> hepeup.ICOLUP[i].second >> hepeup.PUP[i][0] >> hepeup.PUP[i][1] >>
0075           hepeup.PUP[i][2] >> hepeup.PUP[i][3] >> hepeup.PUP[i][4] >> hepeup.VTIMUP[i] >> hepeup.SPINUP[i];
0076       if (!in.good())
0077         throw cms::Exception("InvalidFormat") << "Les Houches file contained invalid event"
0078                                                  " in particle line "
0079                                               << (i + 1) << "." << std::endl;
0080     }
0081
0082     while (skipWhitespace(in) == '#') {
0083       std::string line;
0084       std::getline(in, line);
0085       std::istringstream ss(line);
0086       std::string tag;
0087       ss >> tag;
0088       if (tag == "#pdf") {
0089         pdf = std::make_unique<PDF>();
0090         ss >> pdf->id.first >> pdf->id.second >> pdf->x.first >> pdf->x.second >> pdf->scalePDF >> pdf->xPDF.first >>
0091             pdf->xPDF.second;
0092         if (ss.bad()) {
0093           edm::LogWarning("Generator|LHEInterface") << "Les Houches event contained"
0094                                                        " unparseable PDF information."
0095                                                     << std::endl;
0096           pdf.reset();
0097         } else
0098           continue;
0099       }
0100       comments.push_back(line + "\n");
0101     }
0102
0103     if (!in.eof())
0104       edm::LogWarning("Generator|LHEInterface") << "Les Houches file contained spurious"
0105                                                    " content after event data."
0106                                                 << std::endl;
0107   }
0108
0109   LHEEvent::LHEEvent(const std::shared_ptr<LHERunInfo> &runInfo, const HEPEUP &hepeup)
0110       : runInfo(runInfo), hepeup(hepeup), counted(false), readAttemptCounter(0), npLO_(-99), npNLO_(-99), evtnum_(-1) {}
0111
0112   LHEEvent::LHEEvent(const std::shared_ptr<LHERunInfo> &runInfo,
0113                      const HEPEUP &hepeup,
0114                      const LHEEventProduct::PDF *pdf,
0115                      const std::vector<std::string> &comments)
0116       : runInfo(runInfo),
0117         hepeup(hepeup),
0118         pdf(pdf ? new PDF(*pdf) : nullptr),
0119         comments(comments),
0120         counted(false),
0121         readAttemptCounter(0),
0122         npLO_(-99),
0123         npNLO_(-99),
0124         evtnum_(-1) {}
0125
0126   LHEEvent::LHEEvent(const std::shared_ptr<LHERunInfo> &runInfo, const LHEEventProduct &product)
0127       : runInfo(runInfo),
0128         hepeup(product.hepeup()),
0129         pdf(product.pdf() ? new PDF(*product.pdf()) : nullptr),
0130         weights_(product.weights()),
0131         comments(product.comments_begin(), product.comments_end()),
0132         counted(false),
0133         readAttemptCounter(0),
0134         originalXWGTUP_(product.originalXWGTUP()),
0135         scales_(product.scales()),
0136         npLO_(product.npLO()),
0137         npNLO_(product.npNLO()),
0138         evtnum_(product.evtnum()) {}
0139
0140   LHEEvent::~LHEEvent() {}
0141
0142   void LHEEvent::removeParticle(HEPEUP &hepeup, int index) {
0143     index--;
0144     if (index < 0 || index >= hepeup.NUP) {
0145       edm::LogError("Generator|LHEInterface")
0146           << "removeParticle: Index " << (index + 1) << " out of bounds." << std::endl;
0147       return;
0148     }
0149
0150     std::pair<int, int> mo = hepeup.MOTHUP[index];
0151
0152     hepeup.IDUP.erase(hepeup.IDUP.begin() + index);
0153     hepeup.ISTUP.erase(hepeup.ISTUP.begin() + index);
0154     hepeup.MOTHUP.erase(hepeup.MOTHUP.begin() + index);
0155     hepeup.ICOLUP.erase(hepeup.ICOLUP.begin() + index);
0156     hepeup.PUP.erase(hepeup.PUP.begin() + index);
0157     hepeup.VTIMUP.erase(hepeup.VTIMUP.begin() + index);
0158     hepeup.SPINUP.erase(hepeup.SPINUP.begin() + index);
0159
0160     hepeup.NUP--;
0161
0162     index++;
0163     for (int i = 0; i < hepeup.NUP; i++) {
0164       if (hepeup.MOTHUP[i].first == index) {
0165         if (hepeup.MOTHUP[i].second > 0)
0166           edm::LogError("Generator|LHEInterface")
0167               << "removeParticle: Particle " << (i + 2) << " has two mothers." << std::endl;
0168         hepeup.MOTHUP[i] = mo;
0169       }
0170
0171       if (hepeup.MOTHUP[i].first > index)
0172         hepeup.MOTHUP[i].first--;
0173       if (hepeup.MOTHUP[i].second > index)
0174         hepeup.MOTHUP[i].second--;
0175     }
0176   }
0177
0178   void LHEEvent::removeResonances(const std::vector<int> &ids) {
0179     for (int i = 1; i <= hepeup.NUP; i++) {
0180       int id = std::abs(hepeup.IDUP[i - 1]);
0181       if (hepeup.MOTHUP[i - 1].first > 0 && hepeup.MOTHUP[i - 1].second > 0 &&
0182           std::find(ids.begin(), ids.end(), id) != ids.end())
0183         removeParticle(hepeup, i--);
0184     }
0185   }
0186
0187   void LHEEvent::count(LHERunInfo::CountMode mode, double weight, double matchWeight) {
0188     if (counted)
0189       edm::LogWarning("Generator|LHEInterface") << "LHEEvent::count called twice on same event!" << std::endl;
0190
0191     runInfo->count(hepeup.IDPRUP, mode, hepeup.XWGTUP, weight, matchWeight);
0192
0193     counted = true;
0194   }
0195
0196   void LHEEvent::fillPdfInfo(HepMC::PdfInfo *info) const {
0197     if (pdf.get()) {
0198       info->set_id1(pdf->id.first);
0199       info->set_id2(pdf->id.second);
0200       info->set_x1(pdf->x.first);
0201       info->set_x2(pdf->x.second);
0202       info->set_pdf1(pdf->xPDF.first);
0203       info->set_pdf2(pdf->xPDF.second);
0204       info->set_scalePDF(pdf->scalePDF);
0205     } else if (hepeup.NUP >= 2) {
0206       const HEPRUP *heprup = getHEPRUP();
0207       info->set_id1(hepeup.IDUP[0] == 21 ? 0 : hepeup.IDUP[0]);
0208       info->set_id2(hepeup.IDUP[1] == 21 ? 0 : hepeup.IDUP[1]);
0209       info->set_x1(std::abs(hepeup.PUP[0][2] / heprup->EBMUP.first));
0210       info->set_x2(std::abs(hepeup.PUP[1][2] / heprup->EBMUP.second));
0211       info->set_pdf1(-1.0);
0212       info->set_pdf2(-1.0);
0213       info->set_scalePDF(hepeup.SCALUP);
0214     } else {
0215       info->set_x1(-1.0);
0216       info->set_x2(-1.0);
0217       info->set_pdf1(-1.0);
0218       info->set_pdf2(-1.0);
0219       info->set_scalePDF(hepeup.SCALUP);
0220     }
0221   }
0222
0223   void LHEEvent::fillEventInfo(HepMC::GenEvent *event) const {
0224     event->set_signal_process_id(hepeup.IDPRUP);
0225     event->set_event_scale(hepeup.SCALUP);
0226     event->set_alphaQED(hepeup.AQEDUP);
0227     event->set_alphaQCD(hepeup.AQCDUP);
0228   }
0229
0230   std::unique_ptr<HepMC::GenEvent> LHEEvent::asHepMCEvent() const {
0231     std::unique_ptr<HepMC::GenEvent> hepmc(new HepMC::GenEvent);
0232
0233     hepmc->set_signal_process_id(hepeup.IDPRUP);
0234     hepmc->set_event_scale(hepeup.SCALUP);
0235     hepmc->set_alphaQED(hepeup.AQEDUP);
0236     hepmc->set_alphaQCD(hepeup.AQCDUP);
0237
0238     unsigned int nup = hepeup.NUP;  // particles in event
0239
0240     // any particles in HEPEUP block?
0241     if (!nup) {
0242       edm::LogWarning("Generator|LHEInterface") << "Les Houches Event does not contain any partons. "
0243                                                 << "Not much to convert.";
0244       return hepmc;
0245     }
0246
0247     // stores (pointers to) converted particles
0248     std::vector<HepMC::GenParticle *> genParticles;
0249     std::vector<HepMC::GenVertex *> genVertices;
0250
0251     // I. convert particles
0252     for (unsigned int i = 0; i < nup; i++)
0253       genParticles.push_back(makeHepMCParticle(i));
0254
0255     // II. loop again to build vertices
0256     for (unsigned int i = 0; i < nup; i++) {
0257       unsigned int mother1 = hepeup.MOTHUP.at(i).first;
0258       unsigned int mother2 = hepeup.MOTHUP.at(i).second;
0259       double cTau = hepeup.VTIMUP.at(i);  // decay time
0260
0261       // current particle has a mother? --- Sorry, parent! We're PC.
0262       if (mother1) {
0263         mother1--;  // FORTRAN notation!
0264         if (mother2)
0265           mother2--;
0266         else
0267           mother2 = mother1;
0268
0269         HepMC::GenParticle *in_par = genParticles.at(mother1);
0270         HepMC::GenVertex *current_vtx = in_par->end_vertex();  // vertex of first mother
0271
0272         if (!current_vtx) {
0273           current_vtx = new HepMC::GenVertex(HepMC::FourVector(0, 0, 0, cTau));
0274
0275           // add vertex to event
0276           genVertices.push_back(current_vtx);
0277         }
0278
0279         for (unsigned int j = mother1; j <= mother2; j++)  // set mother-daughter relations
0280           if (!genParticles.at(j)->end_vertex())
0281             current_vtx->add_particle_in(genParticles.at(j));
0282
0283         // connect THIS outgoing particle to current vertex
0284         current_vtx->add_particle_out(genParticles.at(i));
0285       }
0286     }
0287
0288     checkHepMCTree(hepmc.get());
0289
0290     // III. restore color flow
0291     // ok, nobody knows how to do it so far...
0292
0293     // IV. fill run information
0294     const HEPRUP *heprup = getHEPRUP();
0295
0296     // set beam particles
0297     HepMC::GenParticle *b1 = new HepMC::GenParticle(
0298         HepMC::FourVector(0.0, 0.0, +heprup->EBMUP.first, heprup->EBMUP.first), heprup->IDBMUP.first);
0299     HepMC::GenParticle *b2 = new HepMC::GenParticle(
0300         HepMC::FourVector(0.0, 0.0, -heprup->EBMUP.second, heprup->EBMUP.second), heprup->IDBMUP.second);
0301     b1->set_status(3);
0302     b2->set_status(3);
0303
0304     HepMC::GenVertex *v1 = new HepMC::GenVertex();
0305     HepMC::GenVertex *v2 = new HepMC::GenVertex();
0306     v1->add_particle_in(b1);
0307     v2->add_particle_in(b2);
0308
0309     hepmc->add_vertex(v1);
0310     hepmc->add_vertex(v2);
0311     hepmc->set_beam_particles(b1, b2);
0312
0313     // first two particles have to be the hard partons going into the interaction
0314     if (genParticles.size() >= 2) {
0315       if (!genParticles.at(0)->production_vertex() && !genParticles.at(1)->production_vertex()) {
0316         v1->add_particle_out(genParticles.at(0));
0317         v2->add_particle_out(genParticles.at(1));
0318       } else
0319         edm::LogWarning("Generator|LHEInterface") << "Initial partons do already have a"
0320                                                      " production vertex. "
0321                                                   << std::endl
0322                                                   << "Beam particles not connected.";
0323     } else
0324       edm::LogWarning("Generator|LHEInterface") << "Can't find any initial partons to be"
0325                                                    " connected to the beam particles.";
0326
0327     for (std::vector<HepMC::GenVertex *>::const_iterator iter = genVertices.begin(); iter != genVertices.end(); ++iter)
0328       hepmc->add_vertex(*iter);
0329
0330     // do some more consistency checks
0331     for (unsigned int i = 0; i < nup; i++) {
0332       if (!genParticles.at(i)->parent_event()) {
0333         edm::LogWarning("Generator|LHEInterface") << "Not all LHE particles could be stored"
0334                                                      "  stored in the HepMC event. "
0335                                                   << std::endl
0336                                                   << "Check the mother-daughter relations"
0337                                                      " in the given LHE input file.";
0338         break;
0339       }
0340     }
0341
0342     hepmc->set_signal_process_vertex(const_cast<HepMC::GenVertex *>(findSignalVertex(hepmc.get(), false)));
0343
0344     return hepmc;
0345   }
0346
0347   HepMC::GenParticle *LHEEvent::makeHepMCParticle(unsigned int i) const {
0348     HepMC::GenParticle *particle = new HepMC::GenParticle(
0349         HepMC::FourVector(hepeup.PUP.at(i)[0], hepeup.PUP.at(i)[1], hepeup.PUP.at(i)[2], hepeup.PUP.at(i)[3]),
0350         hepeup.IDUP.at(i));
0351
0352     int status = hepeup.ISTUP.at(i);
0353
0354     particle->set_generated_mass(hepeup.PUP.at(i)[4]);
0355     particle->set_status(status > 0 ? (status == 2 ? 3 : status) : 3);
0356
0357     return particle;
0358   }
0359
0360   bool LHEEvent::checkHepMCTree(const HepMC::GenEvent *event) {
0361     double px = 0, py = 0, pz = 0, E = 0;
0362
0363     for (HepMC::GenEvent::particle_const_iterator iter = event->particles_begin(); iter != event->particles_end();
0364          iter++) {
0365       int status = (*iter)->status();
0366       HepMC::FourVector fv = (*iter)->momentum();
0367
0368       // incoming particles
0369       if (status == 3 && *iter != event->beam_particles().first && *iter != event->beam_particles().second) {
0370         px -= fv.px();
0371         py -= fv.py();
0372         pz -= fv.pz();
0373         E -= fv.e();
0374       }
0375
0376       // outgoing particles
0377       if (status == 1) {
0378         px += fv.px();
0379         py += fv.py();
0380         pz += fv.pz();
0381         E += fv.e();
0382       }
0383     }
0384
0385     if (px * px + py * py + pz * pz + E * E > 0.1) {
0386       edm::LogWarning("Generator|LHEInterface")
0387           << "Energy-momentum badly conserved. " << std::setprecision(3) << "sum p_i  = [" << std::setw(7) << E << ", "
0388           << std::setw(7) << px << ", " << std::setw(7) << py << ", " << std::setw(7) << pz << "]";
0389
0390       return false;
0391     }
0392
0393     return true;
0394   }
0395
0396   const HepMC::GenVertex *LHEEvent::findSignalVertex(const HepMC::GenEvent *event, bool status3) {
0397     double largestMass2 = -9.0e-30;
0398     const HepMC::GenVertex *vertex = nullptr;
0399     for (HepMC::GenEvent::vertex_const_iterator iter = event->vertices_begin(); iter != event->vertices_end(); ++iter) {
0400       if ((*iter)->particles_in_size() < 2)
0401         continue;
0402       if ((*iter)->particles_out_size() < 1 ||
0403           ((*iter)->particles_out_size() == 1 &&
0404            (!(*(*iter)->particles_out_const_begin())->end_vertex() ||
0405             !(*(*iter)->particles_out_const_begin())->end_vertex()->particles_out_size())))
0406         continue;
0407
0408       double px = 0.0, py = 0.0, pz = 0.0, E = 0.0;
0409       bool hadStatus3 = false;
0410       for (HepMC::GenVertex::particles_out_const_iterator iter2 = (*iter)->particles_out_const_begin();
0411            iter2 != (*iter)->particles_out_const_end();
0412            ++iter2) {
0413         hadStatus3 = hadStatus3 || (*iter2)->status() == 3;
0414         px += (*iter2)->momentum().px();
0415         py += (*iter2)->momentum().py();
0416         pz += (*iter2)->momentum().pz();
0417         E += (*iter2)->momentum().e();
0418       }
0419       if (status3 && !hadStatus3)
0420         continue;
0421
0422       double mass2 = E * E - (px * px + py * py + pz * pz);
0423       if (mass2 > largestMass2) {
0424         vertex = *iter;
0425         largestMass2 = mass2;
0426       }
0427     }
0428
0429     return vertex;
0430   }
0431
0432   static void fixSubTree(HepMC::GenVertex *vertex,
0433                          HepMC::FourVector &_time,
0434                          std::set<const HepMC::GenVertex *> &visited) {
0435     HepMC::FourVector time = _time;
0436     HepMC::FourVector curTime = vertex->position();
0437     bool needsFixup = curTime.t() < time.t();
0438
0439     if (!visited.insert(vertex).second && !needsFixup)
0440       return;
0441
0442     if (needsFixup)
0443       vertex->set_position(time);
0444     else
0445       time = curTime;
0446
0447     for (HepMC::GenVertex::particles_out_const_iterator iter = vertex->particles_out_const_begin();
0448          iter != vertex->particles_out_const_end();
0449          ++iter) {
0450       HepMC::GenVertex *endVertex = (*iter)->end_vertex();
0451       if (endVertex)
0452         fixSubTree(endVertex, time, visited);
0453     }
0454   }
0455
0456   void LHEEvent::fixHepMCEventTimeOrdering(HepMC::GenEvent *event) {
0457     std::set<const HepMC::GenVertex *> visited;
0458     HepMC::FourVector zeroTime;
0459     for (HepMC::GenEvent::vertex_iterator iter = event->vertices_begin(); iter != event->vertices_end(); ++iter)
0460       fixSubTree(*iter, zeroTime, visited);
0461   }
0462
0463 }  // namespace lhef