BDSParallelWorldUtilities.cc

/* 
Beam Delivery Simulation (BDSIM) Copyright (C) BDSIM Collaboration, 2001 - 2026.
 
This file is part of BDSIM.
 
BDSIM is free software: you can redistribute it and/or modify 
it under the terms of the GNU General Public License as published 
by the Free Software Foundation version 3 of the License.
 
BDSIM is distributed in the hope that it will be useful, but 
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with BDSIM.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "BDSAcceleratorModel.hh"
#include "BDSDebug.hh"
#include "BDSException.hh"
#include "BDSGlobalConstants.hh"
#include "BDSLinkDetectorConstruction.hh"
#include "BDSParallelWorldCurvilinear.hh"
#include "BDSParallelWorldCurvilinearBridge.hh"
#include "BDSParallelWorldImportance.hh"
#include "BDSParallelWorldInfo.hh"
#include "BDSParallelWorldPlacementFields.hh"
#include "BDSParallelWorldSampler.hh"
#include "BDSParallelWorldUtilities.hh"
#include "BDSParser.hh"
#include "BDSSamplerType.hh"
#include "BDSUtilities.hh"
 
#include "parser/element.h"
#include "parser/fastlist.h"
#include "parser/placement.h"
 
#include "G4GeometrySampler.hh"
#include "G4ImportanceBiasing.hh"
#include "G4IStore.hh"
#include "G4ParallelWorldPhysics.hh"
#include "G4VModularPhysicsList.hh"
#include "G4VUserDetectorConstruction.hh"
#include "G4VUserParallelWorld.hh"
 
#include "globals.hh"
 
#include <map>
#include <vector>
 
std::vector<BDSParallelWorldInfo> BDS::NumberOfExtraWorldsRequired()
{
  std::vector<BDSParallelWorldInfo> worlds;
  
  const std::vector<GMAD::Placement> placements = BDSParser::Instance()->GetPlacements();
  for (const auto& pl : placements)
    {// loop over all placement definitions and see if any are beam line placements
      if (!pl.sequence.empty()) // it's a beam line placement
      {// curvilinear world required at least
        G4bool samplerWorldRequired = false;
        for (const auto& el : BDSParser::Instance()->GetSequence(pl.sequence))
        {// do any elements require a sampler -> sampler world required
          BDSSamplerType sType = BDS::DetermineSamplerType(el.samplerType);
          if (sType != BDSSamplerType::none)
          {
            samplerWorldRequired = true;
            break; // no need to loop over rest of sequence
          }
        }
        BDSParallelWorldInfo info(pl.sequence, true, samplerWorldRequired, pl.name);
        worlds.push_back(info);
      }
    }
  return worlds;
}
 
std::vector<G4VUserParallelWorld*> BDS::ConstructAndRegisterParallelWorlds(G4VUserDetectorConstruction* massWorld,
                                                                           G4bool buildSamplerWorld,
                                                                           G4bool buildPlacementFieldsWorld)
{
  BDSAcceleratorModel* acceleratorModel = BDSAcceleratorModel::Instance();
 
  // registry of all created worlds that require the physics process so
  // that their boundaries affect tracking
  std::vector<G4VUserParallelWorld*> worldsRequiringPhysics;
 
  // standard worlds
  if (buildSamplerWorld) // optional
    {
      auto samplerWorld = new BDSParallelWorldSampler("main");
      massWorld->RegisterParallelWorld(samplerWorld);
      auto massWorldBDS = dynamic_cast<BDSLinkDetectorConstruction*>(massWorld);
      if (massWorldBDS)
        {
          G4int samplerWorldID = massWorld->GetNumberOfParallelWorld() - 1;
          massWorldBDS->SetSamplerWorldID(samplerWorldID);
        }
      acceleratorModel->RegisterParallelWorld(samplerWorld);
      worldsRequiringPhysics.push_back(dynamic_cast<G4VUserParallelWorld*>(samplerWorld));
    }
 
  auto curvilinearWorld       = new BDSParallelWorldCurvilinear("main");
  auto curvilinearBridgeWorld = new BDSParallelWorldCurvilinearBridge("main");
  massWorld->RegisterParallelWorld(curvilinearWorld);
  massWorld->RegisterParallelWorld(curvilinearBridgeWorld);
 
  // G4VUserDetectorConstruction doesn't delete parallel worlds so we should
  acceleratorModel->RegisterParallelWorld(curvilinearWorld);
  acceleratorModel->RegisterParallelWorld(curvilinearBridgeWorld);
 
  // extra worlds for additional beam line placements
  std::vector<BDSParallelWorldInfo> worldInfos = BDS::NumberOfExtraWorldsRequired();
 
  for (const auto& info : worldInfos)
    {
      if (info.curvilinearWorld)
        {
          auto cLWorld       = new BDSParallelWorldCurvilinear(info.curvilinearWorldName);
          auto cLBridgeWorld = new BDSParallelWorldCurvilinearBridge(info.curvilinearWorldName);
          massWorld->RegisterParallelWorld(cLWorld);
          massWorld->RegisterParallelWorld(cLBridgeWorld);
          acceleratorModel->RegisterParallelWorld(cLWorld);
          acceleratorModel->RegisterParallelWorld(cLBridgeWorld);
        }
      if (info.samplerWorld)
        {
          auto sWorld = new BDSParallelWorldSampler(info.sequenceName);
          acceleratorModel->RegisterParallelWorld(sWorld);
          worldsRequiringPhysics.push_back(dynamic_cast<G4VUserParallelWorld*>(sWorld));
          massWorld->RegisterParallelWorld(sWorld);
        }
    }
 
  // only create the importance parallel world if the file is specified
  if (BDSGlobalConstants::Instance()->UseImportanceSampling())
    {
      G4String importanceWorldGeometryFile = BDSGlobalConstants::Instance()->ImportanceWorldGeometryFile();
      G4String importanceVolumeMapFile     = BDSGlobalConstants::Instance()->ImportanceVolumeMapFile();
      auto importanceWorld = new BDSParallelWorldImportance("main",
                                                            importanceWorldGeometryFile,
                                                            importanceVolumeMapFile);
      acceleratorModel->RegisterParallelWorld(importanceWorld);
      massWorld->RegisterParallelWorld(importanceWorld);
      worldsRequiringPhysics.push_back(dynamic_cast<G4VUserParallelWorld*>(importanceWorld));
    }
  
  // optional parallel world for coordinate transforms for fields attached to placements of geometry
  if (buildPlacementFieldsWorld)
    {
      auto placementFieldsPW = new BDSParallelWorldPlacementFields("placement_fields");
      acceleratorModel->RegisterParallelWorld(placementFieldsPW);
      massWorld->RegisterParallelWorld(placementFieldsPW);
    }
 
  return worldsRequiringPhysics;
}
 
std::vector<G4ParallelWorldPhysics*> BDS::ConstructParallelWorldPhysics(const std::vector<G4VUserParallelWorld*>& worlds)
{
  std::vector<G4ParallelWorldPhysics*> result;
  for (auto world : worlds)
    {result.push_back(new G4ParallelWorldPhysics(world->GetName()));}
  return result;
}
 
void BDS::RegisterSamplerPhysics(const std::vector<G4ParallelWorldPhysics*>& processes,
                                 G4VModularPhysicsList* physicsList)
{
  for (auto process : processes)
    {physicsList->RegisterPhysics(process);}
}
 
void BDS::AddIStore(const std::vector<G4VUserParallelWorld*>& worlds)
  {
    BDSParallelWorldImportance* importanceWorld = BDS::GetImportanceSamplingWorld(worlds);
    //only add importance store if the world exists
    if (importanceWorld)
      {importanceWorld->AddIStore();}
    else
      {throw BDSException(__METHOD_NAME__, "Importance sampling world not found.");}
  }
 
void BDS::RegisterImportanceBiasing(const std::vector<G4VUserParallelWorld*>& worlds,
                    G4VModularPhysicsList* physList)
{
  BDSParallelWorldImportance* importanceWorld = BDS::GetImportanceSamplingWorld(worlds);
 
  // create world geometry sampler
  G4GeometrySampler* pgs = new G4GeometrySampler(importanceWorld->GetWorldVolume(), "neutron");
  pgs->SetParallel(true);
  physList->RegisterPhysics(new G4ImportanceBiasing(pgs,importanceWorld->GetName()));
}
 
BDSParallelWorldImportance* BDS::GetImportanceSamplingWorld(const std::vector<G4VUserParallelWorld*>& worlds)
{
  // get importance world
  G4String importanceWorldName = "importanceWorld_main";
  G4VUserParallelWorld* importanceWorld = nullptr;
  for (auto world : worlds)
    {
      if (std::strcmp(world->GetName(),importanceWorldName) == 0)
        {importanceWorld = world; break;}
    }
  BDSParallelWorldImportance* iworld = dynamic_cast<BDSParallelWorldImportance*>(importanceWorld);
  return iworld;
}