Sherpa_i.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#include "AtlasHepMC/GenEvent.h"
#include "TruthUtils/HepMCHelpers.h"
#include "GaudiKernel/MsgStream.h"
#include "AthenaBaseComps/AthMsgStreamMacros.h"
#include "AthenaKernel/RNGWrapper.h"
 
#include "Sherpa_i/Sherpa_i.h"
 
 
#include "ATOOLS/Org/CXXFLAGS_PACKAGES.H"
#ifdef HEPMC3
#undef USING__HEPMC2
#else
#undef USING__HEPMC3
#endif
#include "SHERPA/Main/Sherpa.H"
#include "SHERPA/Initialization/Initialization_Handler.H"
#ifdef IS_SHERPA_3
#include "ATOOLS/Phys/Variations.H"
#else
#include "SHERPA/Tools/Variations.H"
#endif
#include "ATOOLS/Org/Exception.H"
#include "ATOOLS/Org/Run_Parameter.H"
 
#include <utility> //std::ignore
#include <cstdio>
#include <cstring>
#include <mutex>
#include <signal.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "CLHEP/Random/RandFlat.h"
 
CLHEP::HepRandomEngine* p_rndEngine{};
 
Sherpa_i::Sherpa_i(const std::string& name, ISvcLocator* pSvcLocator)
  : GenModule(name, pSvcLocator)
{
  #ifdef IS_SHERPA_3
  declareProperty("BaseFragment", m_inputfiles["Base.yaml"] = "");
  declareProperty("RunCard", m_inputfiles["Sherpa.yaml"] = "");
  #endif
}
 
 
 
StatusCode Sherpa_i::genInitialize(){
  if (m_plugincode != "") {
    compilePlugin(m_plugincode);
    #ifndef IS_SHERPA_3
    m_params.value().push_back("SHERPA_LDADD=Sherpa_iPlugin");
    #endif
  }
 
  ATH_MSG_INFO("Sherpa initialising...");
 
  #ifdef IS_SHERPA_3
  for (auto& inputfile : m_inputfiles) {
    // remove first line and last character containing '"'
    // TODO fix Python/C++ string passing, to not contain " in first place
    inputfile.second.erase(0, inputfile.second.find("\n") + 1);
    inputfile.second.pop_back();
  }
  #endif
 
  ATH_MSG_DEBUG("... compiling plugin code");
  if (m_plugincode != "") {
    compilePlugin(m_plugincode);
    #ifdef IS_SHERPA_3
    m_inputfiles["Base.yaml"] += "SHERPA_LDADD: Sherpa_iPlugin \n";
    #else
    m_params.value().push_back("SHERPA_LDADD=Sherpa_iPlugin");
    #endif
  }
 
  ATH_MSG_DEBUG("... seeding Athena random number generator");
  p_rndEngine = getRandomEngineDuringInitialize("SHERPA", m_randomSeed, m_dsid); // NOT THREAD-SAFE
 
  #ifdef IS_SHERPA_3
  ATH_MSG_DEBUG("... adapting output level");
  if( msg().level()==MSG::FATAL || msg().level()==MSG::ERROR || msg().level()==MSG::WARNING ){
    m_inputfiles["Base.yaml"] += "\nEVT_OUTPUT: 0 \n";
  }
  else if(msg().level()==MSG::INFO){
    m_inputfiles["Base.yaml"] += "\nEVT_OUTPUT: 2 \n";
  }
  else if(msg().level()==MSG::DEBUG){
    m_inputfiles["Base.yaml"] += "\nEVT_OUTPUT: 15 \n";
  }
  else{
    m_inputfiles["Base.yaml"] += "\nEVT_OUTPUT: 15 \n";
  }
 
  ATH_MSG_DEBUG("... writing input files to directory");
  for (auto& inputfile : m_inputfiles) {
    // write input content to file in working directory
    FILE *file = fopen(inputfile.first.c_str(),"w");
    if (!file) {
      ATH_MSG_ERROR("Cannot open " << inputfile.first);
      return StatusCode::FAILURE;
    }
    fputs(inputfile.second.c_str(),file);
    fclose(file);
    ATH_MSG_INFO("Sherpa_i using the following settings in "+inputfile.first);
    ATH_MSG_INFO("\n"+inputfile.second+"\n");
  }
 
  ATH_MSG_DEBUG("... go Sherpa!");
  int argc = 2;
  char** argv = new char*[2];
  argv[0] = new char[7];
  argv[1] = new char[34];
  strcpy(argv[0], "Sherpa");
  strcpy(argv[1], "RUNDATA: [Base.yaml, Sherpa.yaml]");
  p_sherpa = new SHERPA::Sherpa(argc, argv);
  delete [] argv;
  #else
  p_sherpa = new SHERPA::Sherpa();
  #endif
 
 
  #ifdef IS_SHERPA_3
 
  try {
    p_sherpa->InitializeTheRun();
    p_sherpa->InitializeTheEventHandler();
  }
  catch (const ATOOLS::normal_exit& exception) {
    ATH_MSG_ERROR("Normal exit caught, this probably means:");
    ATH_MSG_ERROR("Have to compile Amegic libraries");
    ATH_MSG_ERROR("You probably want to run ./makelibs");
    return StatusCode::FAILURE;
  }
  catch (const ATOOLS::Exception& exception) {
    ATH_MSG_ERROR("Unwanted ATOOLS::exception caught.");
    ATH_MSG_ERROR(exception);
    return StatusCode::FAILURE;
  }
  #else 
 
  try {
    int argc;
    char** argv;
    getParameters(argc, argv);
    p_sherpa->InitializeTheRun(argc,(char **)argv);
    delete [] argv;
 
    p_sherpa->InitializeTheEventHandler();
  }
  catch (const ATOOLS::Exception& exception) {
    if (exception.Class()=="Matrix_Element_Handler" && exception.Type()==ATOOLS::ex::normal_exit) {
      ATH_MSG_ERROR("Have to compile Amegic libraries");
      ATH_MSG_ERROR("You probably want to run ./makelibs");
    }
    else {
      ATH_MSG_ERROR("Unwanted ATOOLS::exception caught.");
      ATH_MSG_ERROR(exception);
    }
    return StatusCode::FAILURE;
  }
  #endif
  catch (const std::exception& exception) {
    ATH_MSG_ERROR("std::exception caught.");
    return StatusCode::FAILURE;
  }
 
  #ifdef HEPMC3
  m_runinfo = std::make_shared<HepMC3::GenRunInfo>();
  struct HepMC3::GenRunInfo::ToolInfo generator = {
    std::string("SHERPA"), 
    std::string(SHERPA_VERSION)+ "." + std::string(SHERPA_SUBVERSION), 
    std::string("Used generator")
  };
  m_runinfo->tools().push_back(std::move(generator));
  #endif
  return StatusCode::SUCCESS;
}
 
 
StatusCode Sherpa_i::callGenerator() {
  ATH_MSG_DEBUG("Sherpa_i in callGenerator()");
  //Re-seed the random number stream
  long seeds[7];
  const EventContext& ctx = Gaudi::Hive::currentContext();
  ATHRNG::calculateSeedsMC21(seeds, "SHERPA",  ctx.eventID().event_number(), m_dsid, m_randomSeed);
  p_rndEngine->setSeeds(seeds, 0); // NOT THREAD-SAFE
 
  do {
    ATH_MSG_DEBUG("Trying to generate event with Sherpa");
  } while (p_sherpa->GenerateOneEvent()==false);
 
  const size_t genEvents = ATOOLS::rpa->gen.NumberOfGeneratedEvents();
  if (genEvents%1000==0) {
    ATH_MSG_INFO("Passed "<<genEvents<<" events.");
  }
 
  return StatusCode::SUCCESS;
}
 
StatusCode Sherpa_i::fillEvt(HepMC::GenEvent* event) {
  ATH_MSG_DEBUG( "Sherpa_i Filling event");
#ifdef HEPMC3
  if (!event->run_info()) event->set_run_info(m_runinfo);
#endif
  p_sherpa->FillHepMCEvent(*event);
 
 
#ifdef HEPMC3
//Weight, MEWeight, WeightNormalisation, NTrials
  if (event->weights().size()>2) {
    double nominal = event->weight("Weight");
    for (const auto& name: event->weight_names()) {
      if (name  == "WeightNormalisation") continue;
      if (name  == "NTrials") continue;
      if (name  == "Weight") continue;
      if (name  == "NTrials") continue;
      if (std::abs(event->weight(name)) > m_variation_weight_cap*std::abs(nominal)) {
        ATH_MSG_INFO("Capping variation" << name << " = " << event->weight(name)/nominal << "*nominal");
        event->weight(name) *= m_variation_weight_cap*std::abs(nominal)/std::abs(event->weight(name));
      }
      ATH_MSG_DEBUG("Sherpa WEIGHT " << name << " value="<< event->weight(name));
    }
  }
#else
  if (event->weights().size()>2) {
    for (size_t i=0; i<event->weights().size(); ++i) {
      if (i>3) { // cap variation weights
        // cap variation weights at m_variation_weight_cap*nominal to avoid spikes from numerical instability
        if (std::abs(event->weights()[i]) > m_variation_weight_cap*std::abs(event->weights()[0])) {
          ATH_MSG_INFO("Capping variation" << i << " = " << event->weights()[i]/event->weights()[0] << "*nominal");
          event->weights()[i] *= m_variation_weight_cap*std::abs(event->weights()[0])/std::abs(event->weights()[i]);
        }
      }
      ATH_MSG_DEBUG("Sherpa WEIGHT " << i << " value="<< event->weights()[i]);
    }
  }
#endif
 
#ifdef HEPMC3
  event->set_units(HepMC3::Units::MEV, HepMC3::Units::MM);
#else
  MC::GeVToMeV(event); //Only scales momenta and masses
#endif
 
 
  return StatusCode::SUCCESS;
}
 
StatusCode Sherpa_i::genFinalize() {
 
  ATH_MSG_INFO("Sherpa_i finalize()");
 
  std::cout << "MetaData: generator = Sherpa" << SHERPA_VERSION << "." << SHERPA_SUBVERSION << std::endl;
  std::cout << "MetaData: cross-section (nb)= " << p_sherpa->TotalXS()/1000.0*m_xsscale << std::endl;
 
  std::cout << "MetaData: PDF = " << p_sherpa->PDFInfo() << std::endl;
 
  std::cout << "Named variations initialised by Sherpa:" << std::endl;
  std::cout << *p_sherpa->GetInitHandler()->GetVariations() << std::endl;
 
  p_sherpa->SummarizeRun();
 
  if (m_cleanup) {
    ATH_MSG_INFO("Deleting left-over files from working directory.");
    system("rm -rf Results.db Process MIG_*.db MPI_*.dat libSherpa*.so libProc*.so");
  }
 
  return StatusCode::SUCCESS;
}
 
 
#ifndef IS_SHERPA_3
void Sherpa_i::getParameters(int &argc, char** &argv) {
  std::vector<std::string> params;
 
  // set some ATLAS specific default values as a starting point
  params.push_back("EXTERNAL_RNG=Atlas_RNG");
 
  /***
      Adopt Atlas Debug Level Scheme
  ***/
 
  std::string verbose_arg;
  MsgStream log(msgSvc(), name());
  if( log.level()==MSG::FATAL || log.level()==MSG::ERROR || log.level()==MSG::WARNING ){
    params.push_back("OUTPUT=0");
  }
  else if(log.level()==MSG::INFO){
    params.push_back("OUTPUT=2");
  }
  else if(log.level()==MSG::DEBUG){
    params.push_back("OUTPUT=3");
  }
  else{
    params.push_back("OUTPUT=15");
  }
 
  // disregard manual RUNDATA setting if run card given in JO
  if (m_runcard != "") m_params.value().push_back("RUNDATA=Run.dat");
 
  // allow to overwrite all parameters from JO file
  params.insert(params.begin()+params.size(), m_params.begin(), m_params.end());
 
  // create Run.dat file if runcard explicitely given
  if (m_runcard != "") {
    FILE *file = fopen("Run.dat","w");
    if (!file) {
      ATH_MSG_ERROR("Cannot open Run.dat");
    }
    else {
      fputs(m_runcard.value().c_str(),file);
      fclose(file);
    }
  }
 
  /***
      Convert into Sherpas argc/argv arguments
  ***/
  argc = 1+params.size();
  argv = new char * [ 1+params.size() ];
  argv[0] = new char[7];
  strcpy(argv[0], "Sherpa");
 
  ATH_MSG_INFO("Sherpa_i using the following Arguments");
  ATH_MSG_INFO(m_runcard);
  for(size_t i=0; i<params.size(); i++) {
    ATH_MSG_INFO(" [ " << params[i] << " ] ");
    argv[i+1] = new char[params[i].size()+1];
    strcpy(argv[i+1], params[i].c_str());
  }
  ATH_MSG_INFO("End Sherpa_i Argument List");
  ATH_MSG_INFO("Further Sherpa initialisation output will be redirected to the LOG_FILE specified above.");
 
}
#endif
 
void Sherpa_i::compilePlugin(const std::string& pluginCode) {
  // TODO: not very pretty, should we eventually do this in Python instead (base fragment)
  FILE *file = fopen("Sherpa_iPlugin.C","w");
  if (!file) {
    ATH_MSG_ERROR("Cannot open Sherpa_iPlugin.C");
  }
  else {
    fputs(pluginCode.c_str(),file);
    fclose(file);
  }
  std::string command;
  // Python -> C++ string conversion seems to add quote character as first
  // and last line if the string contains quotes (like always in a plugin)
  // thus removing them here
  command += "tail -n +2 Sherpa_iPlugin.C | head -n -1 > Sherpa_iPlugin.C.tmp; mv Sherpa_iPlugin.C.tmp Sherpa_iPlugin.C; ";
  command += "g++ -shared -std=c++0x -g ";
  command += "-I`Sherpa-config --incdir` ";
  command += "`Sherpa-config --ldflags` ";
  command += "-I$FASTJETPATH/include ";
  command += "-fPIC -o libSherpa_iPlugin.so Sherpa_iPlugin.C";
  ATH_MSG_INFO("Now compiling plugin library using: "+command);
  if (system(command.c_str())!=0) {
    ATH_MSG_ERROR("Error compiling plugin library.");
  }
}

using namespace ATOOLS;
 
Atlas_RNG::Atlas_RNG(CLHEP::HepRandomEngine* engine) :
  External_RNG(), p_engine(engine), m_filename("Config.conf")
{
}
 
Atlas_RNG::~Atlas_RNG() { std::ignore = std::remove(m_filename.c_str()); }
 
double Atlas_RNG::Get(){
 
  return CLHEP::RandFlat::shoot(p_engine);
 
}
 
const std::string Atlas_RNG::GenerateUID() const {
  std::string result{""};
  const int nMax = 26;
  char alphabet[nMax] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g',
                          'h', 'i', 'j', 'k', 'l', 'm', 'n',
                          'o', 'p', 'q', 'r', 's', 't', 'u',
                          'v', 'w', 'x', 'y', 'z' };
  for (size_t i = 0; i < 6; ++i) {
    result += alphabet[rand() % nMax];
  }
  return result;
}
 
void Atlas_RNG::SaveStatus() {
  // We set the file name first time the worker calls SaveStatus
  std::call_once(m_once_flag_atlas_rng, [&](){
      struct stat info;
      if ( !stat("/dev/shm", &info)) {
        m_filename = "/dev/shm/Config.conf.";
      }
      m_filename += GenerateUID();
      std::cout << "RNG state being saved to: " << m_filename << std::endl;
      });
  p_engine->saveStatus(m_filename.c_str());
}
 
void Atlas_RNG::RestoreStatus() { p_engine->restoreStatus(m_filename.c_str()); }
 
// some getter magic to make this random number generator available to sherpa
// DECLARE_GETTER doesn't compile with c++20 in Sherpa versions before 3.
#ifdef IS_SHERPA_3
DECLARE_GETTER(Atlas_RNG,"Atlas_RNG",External_RNG,RNG_Key);
#else
namespace ATOOLS {                                                    
template <> class Getter<External_RNG,RNG_Key,Atlas_RNG,std::less<std::string>>:               
    public Getter_Function<External_RNG,RNG_Key,std::less<std::string>> {                   
private:                                                            
  static Getter<External_RNG,RNG_Key,Atlas_RNG,std::less<std::string>> s_initializer;          
protected:                                                          
  void PrintInfo(std::ostream &str,const size_t width) const;       
  Object_Type *operator()(const Parameter_Type &parameters) const;  
public:                                                             
  Getter(const bool &d=true):           
    Getter_Function<External_RNG,RNG_Key,std::less<std::string>>("Atlas_RNG")
  { SetDisplay(d); }                                              
};                                                                  
}
ATOOLS::Getter<External_RNG,RNG_Key,Atlas_RNG>
ATOOLS::Getter<External_RNG,RNG_Key,Atlas_RNG>::s_initializer(true);
#endif
 
External_RNG *ATOOLS::Getter<External_RNG,RNG_Key,Atlas_RNG>::operator()(const RNG_Key &) const
{ return new Atlas_RNG(p_rndEngine); }
 
void ATOOLS::Getter<External_RNG,RNG_Key,Atlas_RNG>::PrintInfo(std::ostream &str,const size_t) const
{ str<<"Atlas RNG interface"; }