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Geant4/processes/electromagnetic/utils/src/G4TransportationWithMsc.cc

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Differences between /processes/electromagnetic/utils/src/G4TransportationWithMsc.cc (Version 11.3.0) and /processes/electromagnetic/utils/src/G4TransportationWithMsc.cc (Version 11.2)


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 25 //                                                 25 //
 26 // G4TransportationWithMsc                         26 // G4TransportationWithMsc
 27 //                                                 27 //
 28 // Class Description:                              28 // Class Description:
 29 //                                                 29 //
 30 // It is a generic process of transportation w     30 // It is a generic process of transportation with multiple scattering included
 31 // in the step limitation and propagation.         31 // in the step limitation and propagation.
 32 //                                                 32 //
 33 // Original author: Jonas Hahnfeld, 2022           33 // Original author: Jonas Hahnfeld, 2022
 34                                                    34 
 35 // -------------------------------------------     35 // -------------------------------------------------------------------
 36 //                                                 36 //
 37 //....oooOO0OOooo........oooOO0OOooo........oo     37 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
 38 //....oooOO0OOooo........oooOO0OOooo........oo     38 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
 39                                                    39 
 40 #include "G4TransportationWithMsc.hh"              40 #include "G4TransportationWithMsc.hh"
 41                                                    41 
 42 #include "G4DynamicParticle.hh"                    42 #include "G4DynamicParticle.hh"
 43 #include "G4Electron.hh"                           43 #include "G4Electron.hh"
 44 #include "G4EmConfigurator.hh"                     44 #include "G4EmConfigurator.hh"
 45 #include "G4EmDataHandler.hh"                      45 #include "G4EmDataHandler.hh"
 46 #include "G4LossTableBuilder.hh"                   46 #include "G4LossTableBuilder.hh"
 47 #include "G4LossTableManager.hh"                   47 #include "G4LossTableManager.hh"
 48 #include "G4ParticleChangeForGamma.hh"             48 #include "G4ParticleChangeForGamma.hh"
 49 #include "G4ParticleChangeForMSC.hh"               49 #include "G4ParticleChangeForMSC.hh"
 50 #include "G4PhysicalConstants.hh"                  50 #include "G4PhysicalConstants.hh"
 51 #include "G4PhysicsTableHelper.hh"                 51 #include "G4PhysicsTableHelper.hh"
 52 #include "G4PhysicsVector.hh"                      52 #include "G4PhysicsVector.hh"
 53 #include "G4ProductionCutsTable.hh"                53 #include "G4ProductionCutsTable.hh"
 54 #include "G4Step.hh"                               54 #include "G4Step.hh"
 55 #include "G4StepPoint.hh"                          55 #include "G4StepPoint.hh"
 56 #include "G4StepStatus.hh"                         56 #include "G4StepStatus.hh"
 57 #include "G4Track.hh"                              57 #include "G4Track.hh"
 58 #include "G4TransportationProcessType.hh"      << 
 59 #include "G4VMscModel.hh"                          58 #include "G4VMscModel.hh"
 60                                                    59 
 61 //....oooOO0OOooo........oooOO0OOooo........oo     60 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
 62                                                    61 
 63 static constexpr G4double kLowestKinEnergy = 1     62 static constexpr G4double kLowestKinEnergy = 10 * CLHEP::eV;
 64 static constexpr G4double kGeomMin = 0.05 * CL     63 static constexpr G4double kGeomMin = 0.05 * CLHEP::nm;
 65 static constexpr G4double kMinDisplacement2 =      64 static constexpr G4double kMinDisplacement2 = kGeomMin * kGeomMin;
 66                                                    65 
 67 //....oooOO0OOooo........oooOO0OOooo........oo     66 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
 68                                                    67 
 69 G4TransportationWithMsc::G4TransportationWithM     68 G4TransportationWithMsc::G4TransportationWithMsc(ScatteringType type, G4int verbosity)
 70   : G4Transportation(verbosity, "Transportatio     69   : G4Transportation(verbosity, "TransportationWithMsc"), fType(type)
 71 {                                                  70 {
 72   SetProcessSubType(static_cast<G4int>(TRANSPO << 
 73   SetVerboseLevel(1);                              71   SetVerboseLevel(1);
 74                                                    72 
 75   fEmManager = G4LossTableManager::Instance();     73   fEmManager = G4LossTableManager::Instance();
 76   fModelManager = new G4EmModelManager;            74   fModelManager = new G4EmModelManager;
 77                                                    75 
 78   if (type == ScatteringType::MultipleScatteri     76   if (type == ScatteringType::MultipleScattering) {
 79     fParticleChangeForMSC = new G4ParticleChan     77     fParticleChangeForMSC = new G4ParticleChangeForMSC;
 80   }                                                78   }
 81   else if (type == ScatteringType::SingleScatt     79   else if (type == ScatteringType::SingleScattering) {
 82     fParticleChangeForSS = new G4ParticleChang     80     fParticleChangeForSS = new G4ParticleChangeForGamma;
 83     fSecondariesSS = new std::vector<G4Dynamic     81     fSecondariesSS = new std::vector<G4DynamicParticle*>;
 84   }                                                82   }
 85                                                    83 
 86   G4ThreeVector zero;                              84   G4ThreeVector zero;
 87   fSubStepDynamicParticle = new G4DynamicParti     85   fSubStepDynamicParticle = new G4DynamicParticle(G4Electron::Definition(), zero);
 88   fSubStepTrack = new G4Track(fSubStepDynamicP     86   fSubStepTrack = new G4Track(fSubStepDynamicParticle, 0, zero);
 89   fSubStep = new G4Step;                           87   fSubStep = new G4Step;
 90   fSubStepTrack->SetStep(fSubStep);                88   fSubStepTrack->SetStep(fSubStep);
 91 }                                                  89 }
 92                                                    90 
 93 //....oooOO0OOooo........oooOO0OOooo........oo     91 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
 94                                                    92 
 95 G4TransportationWithMsc::~G4TransportationWith     93 G4TransportationWithMsc::~G4TransportationWithMsc()
 96 {                                                  94 {
 97   delete fModelManager;                            95   delete fModelManager;
 98   delete fParticleChangeForMSC;                    96   delete fParticleChangeForMSC;
 99   delete fEmData;                                  97   delete fEmData;
100   delete fParticleChangeForSS;                     98   delete fParticleChangeForSS;
101   delete fSecondariesSS;                           99   delete fSecondariesSS;
102                                                   100 
103   // fSubStepDynamicParticle is owned and also    101   // fSubStepDynamicParticle is owned and also deleted by fSubStepTrack!
104   delete fSubStepTrack;                           102   delete fSubStepTrack;
105   delete fSubStep;                                103   delete fSubStep;
106 }                                                 104 }
107                                                   105 
108 //....oooOO0OOooo........oooOO0OOooo........oo    106 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
109                                                   107 
110 void G4TransportationWithMsc::AddMscModel(G4VM    108 void G4TransportationWithMsc::AddMscModel(G4VMscModel* mscModel, G4int order,
111                                           cons    109                                           const G4Region* region)
112 {                                                 110 {
113   if (fType != ScatteringType::MultipleScatter    111   if (fType != ScatteringType::MultipleScattering) {
114     G4Exception("G4TransportationWithMsc::AddM    112     G4Exception("G4TransportationWithMsc::AddMscModel", "em0051", FatalException,
115                 "not allowed unless type == Mu    113                 "not allowed unless type == MultipleScattering");
116   }                                               114   }
117                                                   115 
118   fModelManager->AddEmModel(order, mscModel, n    116   fModelManager->AddEmModel(order, mscModel, nullptr, region);
119   mscModel->SetParticleChange(fParticleChangeF    117   mscModel->SetParticleChange(fParticleChangeForMSC);
120 }                                                 118 }
121                                                   119 
122 //....oooOO0OOooo........oooOO0OOooo........oo    120 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
123                                                   121 
124 void G4TransportationWithMsc::AddSSModel(G4VEm    122 void G4TransportationWithMsc::AddSSModel(G4VEmModel* model, G4int order, const G4Region* region)
125 {                                                 123 {
126   if (fType != ScatteringType::SingleScatterin    124   if (fType != ScatteringType::SingleScattering) {
127     G4Exception("G4TransportationWithMsc::AddS    125     G4Exception("G4TransportationWithMsc::AddSSModel", "em0051", FatalException,
128                 "not allowed unless type == Si    126                 "not allowed unless type == SingleScattering");
129   }                                               127   }
130                                                   128 
131   fModelManager->AddEmModel(order, model, null    129   fModelManager->AddEmModel(order, model, nullptr, region);
132   model->SetPolarAngleLimit(0.0);                 130   model->SetPolarAngleLimit(0.0);
133   model->SetParticleChange(fParticleChangeForS    131   model->SetParticleChange(fParticleChangeForSS);
134 }                                                 132 }
135                                                   133 
136 //....oooOO0OOooo........oooOO0OOooo........oo    134 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
137                                                   135 
138 void G4TransportationWithMsc::PreparePhysicsTa    136 void G4TransportationWithMsc::PreparePhysicsTable(const G4ParticleDefinition& part)
139 {                                                 137 {
140   if (nullptr == fFirstParticle) {                138   if (nullptr == fFirstParticle) {
141     fFirstParticle = &part;                       139     fFirstParticle = &part;
142     G4VMultipleScattering* ptr = nullptr;         140     G4VMultipleScattering* ptr = nullptr;
143     auto emConfigurator = fEmManager->EmConfig    141     auto emConfigurator = fEmManager->EmConfigurator();
144     emConfigurator->PrepareModels(&part, ptr,     142     emConfigurator->PrepareModels(&part, ptr, this);
145   }                                               143   }
146                                                   144 
147   if (fFirstParticle == &part) {                  145   if (fFirstParticle == &part) {
148     G4bool master = fEmManager->IsMaster();       146     G4bool master = fEmManager->IsMaster();
149     G4LossTableBuilder* bld = fEmManager->GetT    147     G4LossTableBuilder* bld = fEmManager->GetTableBuilder();
150     G4bool baseMat = bld->GetBaseMaterialFlag(    148     G4bool baseMat = bld->GetBaseMaterialFlag();
151     const auto* theParameters = G4EmParameters    149     const auto* theParameters = G4EmParameters::Instance();
152                                                   150 
153     if (master) {                                 151     if (master) {
154       SetVerboseLevel(theParameters->Verbose()    152       SetVerboseLevel(theParameters->Verbose());
155     }                                             153     }
156     else {                                        154     else {
157       SetVerboseLevel(theParameters->WorkerVer    155       SetVerboseLevel(theParameters->WorkerVerbose());
158     }                                             156     }
159                                                   157 
160     const G4int numberOfModels = fModelManager    158     const G4int numberOfModels = fModelManager->NumberOfModels();
161     if (fType == ScatteringType::MultipleScatt    159     if (fType == ScatteringType::MultipleScattering) {
162       for (G4int i = 0; i < numberOfModels; ++    160       for (G4int i = 0; i < numberOfModels; ++i) {
163         auto msc = static_cast<G4VMscModel*>(f    161         auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
                                                   >> 162         msc->SetMasterThread(master);
164         msc->SetPolarAngleLimit(theParameters-    163         msc->SetPolarAngleLimit(theParameters->MscThetaLimit());
165         G4double emax = std::min(msc->HighEner    164         G4double emax = std::min(msc->HighEnergyLimit(), theParameters->MaxKinEnergy());
166         msc->SetHighEnergyLimit(emax);            165         msc->SetHighEnergyLimit(emax);
167         msc->SetUseBaseMaterials(baseMat);        166         msc->SetUseBaseMaterials(baseMat);
168       }                                           167       }
169     }                                             168     }
170     else if (fType == ScatteringType::SingleSc    169     else if (fType == ScatteringType::SingleScattering) {
171       if (master) {                               170       if (master) {
172         if (fEmData == nullptr) {                 171         if (fEmData == nullptr) {
173           fEmData = new G4EmDataHandler(2);       172           fEmData = new G4EmDataHandler(2);
174         }                                         173         }
175                                                   174 
176         fLambdaTable = fEmData->MakeTable(0);     175         fLambdaTable = fEmData->MakeTable(0);
177         bld->InitialiseBaseMaterials(fLambdaTa    176         bld->InitialiseBaseMaterials(fLambdaTable);
178       }                                           177       }
179     }                                             178     }
180                                                   179 
181     fCuts = fModelManager->Initialise(fFirstPa    180     fCuts = fModelManager->Initialise(fFirstParticle, G4Electron::Electron(), verboseLevel);
182   }                                               181   }
183 }                                                 182 }
184                                                   183 
185 //....oooOO0OOooo........oooOO0OOooo........oo    184 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
186                                                   185 
187 void G4TransportationWithMsc::BuildPhysicsTabl    186 void G4TransportationWithMsc::BuildPhysicsTable(const G4ParticleDefinition& part)
188 {                                                 187 {
189   if (fFirstParticle == &part) {                  188   if (fFirstParticle == &part) {
190     fEmManager->BuildPhysicsTable(fFirstPartic    189     fEmManager->BuildPhysicsTable(fFirstParticle);
191                                                   190 
192     if (fEmManager->IsMaster()) {                 191     if (fEmManager->IsMaster()) {
193       if (fType == ScatteringType::SingleScatt    192       if (fType == ScatteringType::SingleScattering) {
194         const auto* theParameters = G4EmParame    193         const auto* theParameters = G4EmParameters::Instance();
195         G4LossTableBuilder* bld = fEmManager->    194         G4LossTableBuilder* bld = fEmManager->GetTableBuilder();
196         const G4ProductionCutsTable* theCouple    195         const G4ProductionCutsTable* theCoupleTable =
197           G4ProductionCutsTable::GetProduction    196           G4ProductionCutsTable::GetProductionCutsTable();
198         std::size_t numOfCouples = theCoupleTa    197         std::size_t numOfCouples = theCoupleTable->GetTableSize();
199                                                   198 
200         G4double emin = theParameters->MinKinE    199         G4double emin = theParameters->MinKinEnergy();
201         G4double emax = theParameters->MaxKinE    200         G4double emax = theParameters->MaxKinEnergy();
202                                                   201 
203         G4double scale = emax / emin;             202         G4double scale = emax / emin;
204         G4int nbin = theParameters->NumberOfBi    203         G4int nbin = theParameters->NumberOfBinsPerDecade() * G4lrint(std::log10(scale));
205         scale = nbin / G4Log(scale);              204         scale = nbin / G4Log(scale);
206                                                   205 
207         G4int bin = G4lrint(scale * G4Log(emax    206         G4int bin = G4lrint(scale * G4Log(emax / emin));
208         bin = std::max(bin, 5);                   207         bin = std::max(bin, 5);
209                                                   208 
210         for (std::size_t i = 0; i < numOfCoupl    209         for (std::size_t i = 0; i < numOfCouples; ++i) {
211           if (!bld->GetFlag(i)) continue;         210           if (!bld->GetFlag(i)) continue;
212                                                   211 
213           // Create physics vector and fill it    212           // Create physics vector and fill it
214           const G4MaterialCutsCouple* couple =    213           const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple((G4int)i);
215                                                   214 
216           auto* aVector = new G4PhysicsLogVect    215           auto* aVector = new G4PhysicsLogVector(emin, emax, bin, /*splineFlag*/ true);
217           fModelManager->FillLambdaVector(aVec    216           fModelManager->FillLambdaVector(aVector, couple, /*startNull*/ false);
218           aVector->FillSecondDerivatives();       217           aVector->FillSecondDerivatives();
219           G4PhysicsTableHelper::SetPhysicsVect    218           G4PhysicsTableHelper::SetPhysicsVector(fLambdaTable, i, aVector);
220         }                                         219         }
221       }                                           220       }
222     }                                             221     }
223     else {                                        222     else {
224       const auto masterProcess = static_cast<c    223       const auto masterProcess = static_cast<const G4TransportationWithMsc*>(GetMasterProcess());
225                                                   224 
226       // Initialisation of models.                225       // Initialisation of models.
227       const G4int numberOfModels = fModelManag    226       const G4int numberOfModels = fModelManager->NumberOfModels();
228       if (fType == ScatteringType::MultipleSca    227       if (fType == ScatteringType::MultipleScattering) {
229         for (G4int i = 0; i < numberOfModels;     228         for (G4int i = 0; i < numberOfModels; ++i) {
230           auto msc = static_cast<G4VMscModel*>    229           auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
231           auto msc0 = static_cast<G4VMscModel*    230           auto msc0 = static_cast<G4VMscModel*>(masterProcess->fModelManager->GetModel(i));
232           msc->SetCrossSectionTable(msc0->GetC    231           msc->SetCrossSectionTable(msc0->GetCrossSectionTable(), false);
233           msc->InitialiseLocal(fFirstParticle,    232           msc->InitialiseLocal(fFirstParticle, msc0);
234         }                                         233         }
235       }                                           234       }
236       else if (fType == ScatteringType::Single    235       else if (fType == ScatteringType::SingleScattering) {
237         this->fLambdaTable = masterProcess->fL    236         this->fLambdaTable = masterProcess->fLambdaTable;
238       }                                           237       }
239     }                                             238     }
240   }                                               239   }
241                                                   240 
242   if (!G4EmParameters::Instance()->IsPrintLock    241   if (!G4EmParameters::Instance()->IsPrintLocked() && verboseLevel > 0) {
243     G4cout << G4endl;                             242     G4cout << G4endl;
244     G4cout << GetProcessName() << ": for " <<     243     G4cout << GetProcessName() << ": for " << part.GetParticleName();
245     if (fMultipleSteps) {                         244     if (fMultipleSteps) {
246       G4cout << " (multipleSteps: 1)";            245       G4cout << " (multipleSteps: 1)";
247     }                                             246     }
248     G4cout << G4endl;                             247     G4cout << G4endl;
249     fModelManager->DumpModelList(G4cout, verbo    248     fModelManager->DumpModelList(G4cout, verboseLevel);
250   }                                               249   }
251 }                                                 250 }
252                                                   251 
253 //....oooOO0OOooo........oooOO0OOooo........oo    252 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
254                                                   253 
255 void G4TransportationWithMsc::StartTracking(G4    254 void G4TransportationWithMsc::StartTracking(G4Track* track)
256 {                                                 255 {
257   auto* currParticle = track->GetParticleDefin    256   auto* currParticle = track->GetParticleDefinition();
258   fIonisation = fEmManager->GetEnergyLossProce    257   fIonisation = fEmManager->GetEnergyLossProcess(currParticle);
259                                                   258 
260   fSubStepDynamicParticle->SetDefinition(currP    259   fSubStepDynamicParticle->SetDefinition(currParticle);
261                                                   260 
262   const G4int numberOfModels = fModelManager->    261   const G4int numberOfModels = fModelManager->NumberOfModels();
263   if (fType == ScatteringType::MultipleScatter    262   if (fType == ScatteringType::MultipleScattering) {
264     for (G4int i = 0; i < numberOfModels; ++i)    263     for (G4int i = 0; i < numberOfModels; ++i) {
265       auto msc = static_cast<G4VMscModel*>(fMo    264       auto msc = static_cast<G4VMscModel*>(fModelManager->GetModel(i));
266       msc->StartTracking(track);                  265       msc->StartTracking(track);
267       msc->SetIonisation(fIonisation, currPart    266       msc->SetIonisation(fIonisation, currParticle);
268     }                                             267     }
269   }                                               268   }
270                                                   269 
271   // Ensure that field propagation state is al    270   // Ensure that field propagation state is also cleared / prepared
272   G4Transportation::StartTracking(track);         271   G4Transportation::StartTracking(track);
273 }                                                 272 }
274                                                   273 
275 //....oooOO0OOooo........oooOO0OOooo........oo    274 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
276                                                   275 
277 G4double G4TransportationWithMsc::AlongStepGet    276 G4double G4TransportationWithMsc::AlongStepGetPhysicalInteractionLength(const G4Track& track,
278                                                   277                                                                         G4double previousStepSize,
279                                                   278                                                                         G4double currentMinimumStep,
280                                                   279                                                                         G4double& proposedSafety,
281                                                   280                                                                         G4GPILSelection* selection)
282 {                                                 281 {
283   *selection = NotCandidateForSelection;          282   *selection = NotCandidateForSelection;
284                                                   283 
285   const G4double physStepLimit = currentMinimu    284   const G4double physStepLimit = currentMinimumStep;
286                                                   285 
287   switch (fType) {                                286   switch (fType) {
288     case ScatteringType::MultipleScattering: {    287     case ScatteringType::MultipleScattering: {
289       // Select the MSC model for the current     288       // Select the MSC model for the current kinetic energy.
290       G4VMscModel* mscModel = nullptr;            289       G4VMscModel* mscModel = nullptr;
291       const G4double ekin = track.GetKineticEn    290       const G4double ekin = track.GetKineticEnergy();
292       const auto* couple = track.GetMaterialCu    291       const auto* couple = track.GetMaterialCutsCouple();
293       const auto* particleDefinition = track.G    292       const auto* particleDefinition = track.GetParticleDefinition();
294       if (physStepLimit > kGeomMin) {             293       if (physStepLimit > kGeomMin) {
295         G4double ekinForSelection = ekin;         294         G4double ekinForSelection = ekin;
296         G4double pdgMass = particleDefinition-    295         G4double pdgMass = particleDefinition->GetPDGMass();
297         if (pdgMass > CLHEP::GeV) {               296         if (pdgMass > CLHEP::GeV) {
298           ekinForSelection *= proton_mass_c2 /    297           ekinForSelection *= proton_mass_c2 / pdgMass;
299         }                                         298         }
300                                                   299 
301         if (ekinForSelection >= kLowestKinEner    300         if (ekinForSelection >= kLowestKinEnergy) {
302           mscModel = static_cast<G4VMscModel*>    301           mscModel = static_cast<G4VMscModel*>(
303             fModelManager->SelectModel(ekinFor    302             fModelManager->SelectModel(ekinForSelection, couple->GetIndex()));
304           if (mscModel == nullptr) {              303           if (mscModel == nullptr) {
305             G4Exception("G4TransportationWithM    304             G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0052", FatalException,
306                         "no MSC model found");    305                         "no MSC model found");
307           }                                       306           }
308           if (!mscModel->IsActive(ekinForSelec    307           if (!mscModel->IsActive(ekinForSelection)) {
309             mscModel = nullptr;                   308             mscModel = nullptr;
310           }                                       309           }
311         }                                         310         }
312       }                                           311       }
313                                                   312 
314       // Call the MSC model to potentially lim    313       // Call the MSC model to potentially limit the step and convert to
315       // geometric path length.                   314       // geometric path length.
316       if (mscModel != nullptr) {                  315       if (mscModel != nullptr) {
317         mscModel->SetCurrentCouple(couple);       316         mscModel->SetCurrentCouple(couple);
318                                                   317 
319         // Use the provided track for the firs    318         // Use the provided track for the first step.
320         const G4Track* currentTrackPtr = &trac    319         const G4Track* currentTrackPtr = &track;
321                                                   320 
322         G4double currentSafety = proposedSafet    321         G4double currentSafety = proposedSafety;
323         G4double currentEnergy = ekin;            322         G4double currentEnergy = ekin;
324                                                   323 
325         G4double stepLimitLeft = physStepLimit    324         G4double stepLimitLeft = physStepLimit;
326         G4double totalGeometryStepLength = 0,     325         G4double totalGeometryStepLength = 0, totalTruePathLength = 0;
327         G4bool firstStep = true, continueStepp    326         G4bool firstStep = true, continueStepping = fMultipleSteps;
328                                                   327 
329         do {                                      328         do {
330           G4double gPathLength = stepLimitLeft    329           G4double gPathLength = stepLimitLeft;
331           G4double tPathLength =                  330           G4double tPathLength =
332             mscModel->ComputeTruePathLengthLim    331             mscModel->ComputeTruePathLengthLimit(*currentTrackPtr, gPathLength);
333           G4bool mscLimitsStep = (tPathLength     332           G4bool mscLimitsStep = (tPathLength < stepLimitLeft);
334           if (!fMultipleSteps && mscLimitsStep    333           if (!fMultipleSteps && mscLimitsStep) {
335             // MSC limits the step.               334             // MSC limits the step.
336             *selection = CandidateForSelection    335             *selection = CandidateForSelection;
337           }                                       336           }
338                                                   337 
339           if (!firstStep) {                       338           if (!firstStep) {
340             // Move the navigator to where the    339             // Move the navigator to where the previous step ended.
341             fLinearNavigator->LocateGlobalPoin    340             fLinearNavigator->LocateGlobalPointWithinVolume(fTransportEndPosition);
342           }                                       341           }
343                                                   342 
344           G4GPILSelection transportSelection;     343           G4GPILSelection transportSelection;
345           G4double geometryStepLength = G4Tran    344           G4double geometryStepLength = G4Transportation::AlongStepGetPhysicalInteractionLength(
346             *currentTrackPtr, previousStepSize    345             *currentTrackPtr, previousStepSize, gPathLength, currentSafety, &transportSelection);
347           if (geometryStepLength < gPathLength    346           if (geometryStepLength < gPathLength) {
348             // Transportation limits the step,    347             // Transportation limits the step, ie the track hit a boundary.
349             *selection = CandidateForSelection    348             *selection = CandidateForSelection;
350             continueStepping = false;             349             continueStepping = false;
351           }                                       350           }
352           if (fTransportEndKineticEnergy != cu    351           if (fTransportEndKineticEnergy != currentEnergy) {
353             // Field propagation changed the e    352             // Field propagation changed the energy, it's not possible to
354             // estimate the continuous energy     353             // estimate the continuous energy loss and continue stepping.
355             continueStepping = false;             354             continueStepping = false;
356           }                                       355           }
357                                                   356 
358           if (firstStep) {                        357           if (firstStep) {
359             proposedSafety = currentSafety;       358             proposedSafety = currentSafety;
360           }                                       359           }
361           totalGeometryStepLength += geometryS    360           totalGeometryStepLength += geometryStepLength;
362                                                   361 
363           // Sample MSC direction change and d    362           // Sample MSC direction change and displacement.
364           const G4double range = mscModel->Get    363           const G4double range = mscModel->GetRange(particleDefinition, currentEnergy, couple);
365                                                   364 
366           tPathLength = mscModel->ComputeTrueS    365           tPathLength = mscModel->ComputeTrueStepLength(geometryStepLength);
367                                                   366 
368           // Protect against wrong t->g->t con    367           // Protect against wrong t->g->t conversion.
369           tPathLength = std::min(tPathLength,     368           tPathLength = std::min(tPathLength, stepLimitLeft);
370                                                   369 
371           totalTruePathLength += tPathLength;     370           totalTruePathLength += tPathLength;
372           if (*selection != CandidateForSelect    371           if (*selection != CandidateForSelection && !mscLimitsStep) {
373             // If neither MSC nor transportati    372             // If neither MSC nor transportation limits the step, we got the
374             // distance we want - make sure we    373             // distance we want - make sure we exit the loop.
375             continueStepping = false;             374             continueStepping = false;
376           }                                       375           }
377           else if (tPathLength >= range) {        376           else if (tPathLength >= range) {
378             // The particle will stop, exit th    377             // The particle will stop, exit the loop.
379             continueStepping = false;             378             continueStepping = false;
380           }                                       379           }
381           else {                                  380           else {
382             stepLimitLeft -= tPathLength;         381             stepLimitLeft -= tPathLength;
383           }                                       382           }
384                                                   383 
385           // Do not sample scattering at the l    384           // Do not sample scattering at the last or at a small step.
386           if (tPathLength < range && tPathLeng    385           if (tPathLength < range && tPathLength > kGeomMin) {
387             static constexpr G4double minSafet    386             static constexpr G4double minSafety = 1.20 * CLHEP::nm;
388             static constexpr G4double sFact =     387             static constexpr G4double sFact = 0.99;
389                                                   388 
390             // The call to SampleScattering()     389             // The call to SampleScattering() *may* directly fill in the changed
391             // direction into fParticleChangeF    390             // direction into fParticleChangeForMSC, so we have to:
392             // 1) Make sure the momentum direc    391             // 1) Make sure the momentum direction is initialized.
393             fParticleChangeForMSC->ProposeMome    392             fParticleChangeForMSC->ProposeMomentumDirection(fTransportEndMomentumDir);
394             // 2) Call SampleScattering(), whi    393             // 2) Call SampleScattering(), which *may* change it.
395             const G4ThreeVector displacement =    394             const G4ThreeVector displacement =
396               mscModel->SampleScattering(fTran    395               mscModel->SampleScattering(fTransportEndMomentumDir, minSafety);
397             // 3) Get the changed direction.      396             // 3) Get the changed direction.
398             fTransportEndMomentumDir = *fParti    397             fTransportEndMomentumDir = *fParticleChangeForMSC->GetProposedMomentumDirection();
399                                                   398 
400             const G4double r2 = displacement.m    399             const G4double r2 = displacement.mag2();
401             if (r2 > kMinDisplacement2) {         400             if (r2 > kMinDisplacement2) {
402               G4bool positionChanged = true;      401               G4bool positionChanged = true;
403               G4double dispR = std::sqrt(r2);     402               G4double dispR = std::sqrt(r2);
404               G4double postSafety =               403               G4double postSafety =
405                 sFact * fpSafetyHelper->Comput    404                 sFact * fpSafetyHelper->ComputeSafety(fTransportEndPosition, dispR);
406                                                   405 
407               // Far away from geometry bounda    406               // Far away from geometry boundary
408               if (postSafety > 0.0 && dispR <=    407               if (postSafety > 0.0 && dispR <= postSafety) {
409                 fTransportEndPosition += displ    408                 fTransportEndPosition += displacement;
410                                                   409 
411                 // Near the boundary              410                 // Near the boundary
412               }                                   411               }
413               else {                              412               else {
414                 // displaced point is definite    413                 // displaced point is definitely within the volume
415                 if (dispR < postSafety) {         414                 if (dispR < postSafety) {
416                   fTransportEndPosition += dis    415                   fTransportEndPosition += displacement;
417                                                   416 
418                   // reduced displacement         417                   // reduced displacement
419                 }                                 418                 }
420                 else if (postSafety > kGeomMin    419                 else if (postSafety > kGeomMin) {
421                   fTransportEndPosition += dis    420                   fTransportEndPosition += displacement * (postSafety / dispR);
422                                                   421 
423                   // very small postSafety        422                   // very small postSafety
424                 }                                 423                 }
425                 else {                            424                 else {
426                   positionChanged = false;        425                   positionChanged = false;
427                 }                                 426                 }
428               }                                   427               }
429               if (positionChanged) {              428               if (positionChanged) {
430                 fpSafetyHelper->ReLocateWithin    429                 fpSafetyHelper->ReLocateWithinVolume(fTransportEndPosition);
431               }                                   430               }
432             }                                     431             }
433           }                                       432           }
434                                                   433 
435           if (continueStepping) {                 434           if (continueStepping) {
436             // Update safety according to the     435             // Update safety according to the geometry distance.
437             if (currentSafety < fEndPointDista    436             if (currentSafety < fEndPointDistance) {
438               currentSafety = 0;                  437               currentSafety = 0;
439             }                                     438             }
440             else {                                439             else {
441               currentSafety -= fEndPointDistan    440               currentSafety -= fEndPointDistance;
442             }                                     441             }
443                                                   442 
444             // Update the kinetic energy accor    443             // Update the kinetic energy according to the continuous loss.
445             currentEnergy = mscModel->GetEnerg    444             currentEnergy = mscModel->GetEnergy(particleDefinition, range - tPathLength, couple);
446                                                   445 
447             // From now on, use the track that    446             // From now on, use the track that we can update below.
448             currentTrackPtr = fSubStepTrack;      447             currentTrackPtr = fSubStepTrack;
449                                                   448 
450             fSubStepDynamicParticle->SetKineti    449             fSubStepDynamicParticle->SetKineticEnergy(currentEnergy);
451             fSubStepDynamicParticle->SetMoment    450             fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
452             fSubStepTrack->SetPosition(fTransp    451             fSubStepTrack->SetPosition(fTransportEndPosition);
453                                                   452 
454             G4StepPoint& subPreStepPoint = *fS    453             G4StepPoint& subPreStepPoint = *fSubStep->GetPreStepPoint();
455             subPreStepPoint.SetMaterialCutsCou    454             subPreStepPoint.SetMaterialCutsCouple(couple);
456             subPreStepPoint.SetPosition(fTrans    455             subPreStepPoint.SetPosition(fTransportEndPosition);
457             subPreStepPoint.SetSafety(currentS    456             subPreStepPoint.SetSafety(currentSafety);
458             subPreStepPoint.SetStepStatus(fAlo    457             subPreStepPoint.SetStepStatus(fAlongStepDoItProc);
459           }                                       458           }
460           firstStep = false;                      459           firstStep = false;
461         } while (continueStepping);               460         } while (continueStepping);
462                                                   461 
463         // Note: currentEnergy is only updated    462         // Note: currentEnergy is only updated if continueStepping is true.
464         // In case field propagation changed t    463         // In case field propagation changed the energy, this flag is
465         // immediately set to false and curren    464         // immediately set to false and currentEnergy is still equal to the
466         // initial kinetic energy stored in ek    465         // initial kinetic energy stored in ekin.
467         if (currentEnergy != ekin) {              466         if (currentEnergy != ekin) {
468           // If field propagation didn't chang    467           // If field propagation didn't change the energy and we potentially
469           // did multiple steps, reset the ene    468           // did multiple steps, reset the energy that G4Transportation will
470           // propose to not subtract the energ    469           // propose to not subtract the energy loss twice.
471           fTransportEndKineticEnergy = ekin;      470           fTransportEndKineticEnergy = ekin;
472           // Also ask for the range again with    471           // Also ask for the range again with the initial energy so it is
473           // correctly cached in the G4VEnergy    472           // correctly cached in the G4VEnergyLossProcess.
474           // FIXME: Asking for a range should     473           // FIXME: Asking for a range should never change the cached values!
475           (void)mscModel->GetRange(particleDef    474           (void)mscModel->GetRange(particleDefinition, ekin, couple);
476         }                                         475         }
477                                                   476 
478         fParticleChange.ProposeTrueStepLength(    477         fParticleChange.ProposeTrueStepLength(totalTruePathLength);
479                                                   478 
480         // Inform G4Transportation that the mo    479         // Inform G4Transportation that the momentum might have changed due
481         // to scattering. We do this unconditi    480         // to scattering. We do this unconditionally to avoid the situation
482         // where the last step is done without    481         // where the last step is done without MSC and G4Transportation reset
483         // the flag, for example when running     482         // the flag, for example when running without field.
484         fMomentumChanged = true;                  483         fMomentumChanged = true;
485                                                   484 
486         return totalGeometryStepLength;           485         return totalGeometryStepLength;
487       }                                           486       }
488       break;                                      487       break;
489     }                                             488     }
490                                                   489 
491     case ScatteringType::SingleScattering: {      490     case ScatteringType::SingleScattering: {
492       // Select the model for the current kine    491       // Select the model for the current kinetic energy.
493       const G4double ekin = track.GetKineticEn    492       const G4double ekin = track.GetKineticEnergy();
494       const auto* couple = track.GetMaterialCu    493       const auto* couple = track.GetMaterialCutsCouple();
495       const auto* particleDefinition = track.G    494       const auto* particleDefinition = track.GetParticleDefinition();
496                                                   495 
497       G4double ekinForSelection = ekin;           496       G4double ekinForSelection = ekin;
498       G4double pdgMass = particleDefinition->G    497       G4double pdgMass = particleDefinition->GetPDGMass();
499       if (pdgMass > CLHEP::GeV) {                 498       if (pdgMass > CLHEP::GeV) {
500         ekinForSelection *= proton_mass_c2 / p    499         ekinForSelection *= proton_mass_c2 / pdgMass;
501       }                                           500       }
502                                                   501 
503       G4VEmModel* currentModel = fModelManager    502       G4VEmModel* currentModel = fModelManager->SelectModel(ekinForSelection, couple->GetIndex());
504       if (currentModel == nullptr) {              503       if (currentModel == nullptr) {
505         G4Exception("G4TransportationWithMsc::    504         G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0052", FatalException,
506                     "no scattering model found    505                     "no scattering model found");
507       }                                           506       }
508       if (!currentModel->IsActive(ekinForSelec    507       if (!currentModel->IsActive(ekinForSelection)) {
509         currentModel = nullptr;                   508         currentModel = nullptr;
510       }                                           509       }
511                                                   510 
512       if (currentModel != nullptr) {              511       if (currentModel != nullptr) {
513         currentModel->SetCurrentCouple(couple)    512         currentModel->SetCurrentCouple(couple);
514         G4int coupleIndex = couple->GetIndex()    513         G4int coupleIndex = couple->GetIndex();
515                                                   514 
516         // Compute mean free path.                515         // Compute mean free path.
517         G4double logEkin = track.GetDynamicPar    516         G4double logEkin = track.GetDynamicParticle()->GetLogKineticEnergy();
518         G4double lambda = ((*fLambdaTable)[cou    517         G4double lambda = ((*fLambdaTable)[coupleIndex])->LogVectorValue(ekin, logEkin);
519         if (lambda > 0.0) {                       518         if (lambda > 0.0) {
520           // Assume that the mean free path an    519           // Assume that the mean free path and dE/dx are constant along the
521           // step, which is a valid approximat    520           // step, which is a valid approximation for most cases.
522           G4double meanFreePath = 1.0 / lambda    521           G4double meanFreePath = 1.0 / lambda;
523           G4double dedx = fIonisation->GetDEDX    522           G4double dedx = fIonisation->GetDEDX(ekin, couple);
524                                                   523 
525           G4double currentSafety = proposedSaf    524           G4double currentSafety = proposedSafety;
526           G4double currentEnergy = ekin;          525           G4double currentEnergy = ekin;
527                                                   526 
528           // Use the provided track for the fi    527           // Use the provided track for the first step.
529           const G4Track* currentTrackPtr = &tr    528           const G4Track* currentTrackPtr = &track;
530                                                   529 
531           G4double stepLimitLeft = physStepLim    530           G4double stepLimitLeft = physStepLimit;
532           G4double totalStepLength = 0;           531           G4double totalStepLength = 0;
533           G4bool firstStep = true, continueSte    532           G4bool firstStep = true, continueStepping = fMultipleSteps;
534                                                   533 
535           do {                                    534           do {
536             G4double interactionLength = meanF    535             G4double interactionLength = meanFreePath * -G4Log(G4UniformRand());
537                                                   536 
538             G4bool ssLimitsStep = (interaction    537             G4bool ssLimitsStep = (interactionLength < stepLimitLeft);
539             G4double gPathLength = stepLimitLe    538             G4double gPathLength = stepLimitLeft;
540             if (ssLimitsStep) {                   539             if (ssLimitsStep) {
541               if (!fMultipleSteps) {              540               if (!fMultipleSteps) {
542                 // Scattering limits the step.    541                 // Scattering limits the step.
543                 *selection = CandidateForSelec    542                 *selection = CandidateForSelection;
544               }                                   543               }
545               gPathLength = interactionLength;    544               gPathLength = interactionLength;
546             }                                     545             }
547                                                   546 
548             if (!firstStep) {                     547             if (!firstStep) {
549               // Move the navigator to where t    548               // Move the navigator to where the previous step ended.
550               fLinearNavigator->LocateGlobalPo    549               fLinearNavigator->LocateGlobalPointWithinVolume(fTransportEndPosition);
551             }                                     550             }
552                                                   551 
553             G4GPILSelection transportSelection    552             G4GPILSelection transportSelection;
554             G4double geometryStepLength = G4Tr    553             G4double geometryStepLength = G4Transportation::AlongStepGetPhysicalInteractionLength(
555               *currentTrackPtr, previousStepSi    554               *currentTrackPtr, previousStepSize, gPathLength, currentSafety, &transportSelection);
556             if (geometryStepLength < gPathLeng    555             if (geometryStepLength < gPathLength) {
557               // Transportation limits the ste    556               // Transportation limits the step, ie the track hit a boundary.
558               *selection = CandidateForSelecti    557               *selection = CandidateForSelection;
559               ssLimitsStep = false;               558               ssLimitsStep = false;
560               continueStepping = false;           559               continueStepping = false;
561             }                                     560             }
562             if (fTransportEndKineticEnergy !=     561             if (fTransportEndKineticEnergy != currentEnergy) {
563               // Field propagation changed the    562               // Field propagation changed the energy, it's not possible to
564               // estimate the continuous energ    563               // estimate the continuous energy loss and continue stepping.
565               continueStepping = false;           564               continueStepping = false;
566             }                                     565             }
567                                                   566 
568             if (firstStep) {                      567             if (firstStep) {
569               proposedSafety = currentSafety;     568               proposedSafety = currentSafety;
570             }                                     569             }
571             totalStepLength += geometryStepLen    570             totalStepLength += geometryStepLength;
572                                                   571 
573             if (*selection != CandidateForSele    572             if (*selection != CandidateForSelection && !ssLimitsStep) {
574               // If neither scattering nor tra    573               // If neither scattering nor transportation limits the step, we
575               // got the distance we want - ma    574               // got the distance we want - make sure we exit the loop.
576               continueStepping = false;           575               continueStepping = false;
577             }                                     576             }
578             else {                                577             else {
579               stepLimitLeft -= geometryStepLen    578               stepLimitLeft -= geometryStepLength;
580             }                                     579             }
581                                                   580 
582             // Update the kinetic energy accor    581             // Update the kinetic energy according to the continuous loss.
583             G4double energyAfterLinearLoss =      582             G4double energyAfterLinearLoss =
584               fTransportEndKineticEnergy - geo    583               fTransportEndKineticEnergy - geometryStepLength * dedx;
585                                                   584 
586             if (ssLimitsStep) {                   585             if (ssLimitsStep) {
587               fSubStepDynamicParticle->SetKine    586               fSubStepDynamicParticle->SetKineticEnergy(energyAfterLinearLoss);
588                                                   587 
589               // The call to SampleSecondaries    588               // The call to SampleSecondaries() directly fills in the changed
590               // direction into fParticleChang    589               // direction into fParticleChangeForSS, so we have to:
591               // 1) Set the momentum direction    590               // 1) Set the momentum direction in dynamic particle.
592               fSubStepDynamicParticle->SetMome    591               fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
593               // 2) Call SampleSecondaries(),     592               // 2) Call SampleSecondaries(), which changes the direction.
594               currentModel->SampleSecondaries(    593               currentModel->SampleSecondaries(fSecondariesSS, couple, fSubStepDynamicParticle,
595                                                   594                                               (*fCuts)[coupleIndex]);
596               // 3) Get the changed direction.    595               // 3) Get the changed direction.
597               fTransportEndMomentumDir = fPart    596               fTransportEndMomentumDir = fParticleChangeForSS->GetProposedMomentumDirection();
598                                                   597 
599               // Check that the model neither     598               // Check that the model neither created secondaries nor proposed
600               // a local energy deposit becaus    599               // a local energy deposit because this process does not know how
601               // to handle these cases.           600               // to handle these cases.
602               if (fSecondariesSS->size() > 0)     601               if (fSecondariesSS->size() > 0) {
603                 G4Exception("G4TransportationW    602                 G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0053", FatalException,
604                             "scattering model     603                             "scattering model created secondaries");
605               }                                   604               }
606               if (fParticleChangeForSS->GetLoc    605               if (fParticleChangeForSS->GetLocalEnergyDeposit() > 0) {
607                 G4Exception("G4TransportationW    606                 G4Exception("G4TransportationWithMsc::AlongStepGPIL", "em0053", FatalException,
608                             "scattering model     607                             "scattering model proposed energy deposit");
609               }                                   608               }
610             }                                     609             }
611                                                   610 
612             if (continueStepping) {               611             if (continueStepping) {
613               // Update safety according to th    612               // Update safety according to the geometry distance.
614               if (currentSafety < fEndPointDis    613               if (currentSafety < fEndPointDistance) {
615                 currentSafety = 0;                614                 currentSafety = 0;
616               }                                   615               }
617               else {                              616               else {
618                 currentSafety -= fEndPointDist    617                 currentSafety -= fEndPointDistance;
619               }                                   618               }
620                                                   619 
621               // Update the energy taking cont    620               // Update the energy taking continuous loss into account.
622               currentEnergy = energyAfterLinea    621               currentEnergy = energyAfterLinearLoss;
623                                                   622 
624               // From now on, use the track th    623               // From now on, use the track that we can update below.
625               currentTrackPtr = fSubStepTrack;    624               currentTrackPtr = fSubStepTrack;
626                                                   625 
627               fSubStepDynamicParticle->SetKine    626               fSubStepDynamicParticle->SetKineticEnergy(currentEnergy);
628               fSubStepDynamicParticle->SetMome    627               fSubStepDynamicParticle->SetMomentumDirection(fTransportEndMomentumDir);
629               fSubStepTrack->SetPosition(fTran    628               fSubStepTrack->SetPosition(fTransportEndPosition);
630                                                   629 
631               G4StepPoint& subPreStepPoint = *    630               G4StepPoint& subPreStepPoint = *fSubStep->GetPreStepPoint();
632               subPreStepPoint.SetMaterialCutsC    631               subPreStepPoint.SetMaterialCutsCouple(couple);
633               subPreStepPoint.SetPosition(fTra    632               subPreStepPoint.SetPosition(fTransportEndPosition);
634               subPreStepPoint.SetSafety(curren    633               subPreStepPoint.SetSafety(currentSafety);
635               subPreStepPoint.SetStepStatus(fA    634               subPreStepPoint.SetStepStatus(fAlongStepDoItProc);
636             }                                     635             }
637             firstStep = false;                    636             firstStep = false;
638           } while (continueStepping);             637           } while (continueStepping);
639                                                   638 
640           // Note: currentEnergy is only updat    639           // Note: currentEnergy is only updated if continueStepping is true.
641           // In case field propagation changed    640           // In case field propagation changed the energy, this flag is
642           // immediately set to false and curr    641           // immediately set to false and currentEnergy is still equal to the
643           // initial kinetic energy stored in     642           // initial kinetic energy stored in ekin.
644           if (currentEnergy != ekin) {            643           if (currentEnergy != ekin) {
645             // If field propagation didn't cha    644             // If field propagation didn't change the energy and we potentially
646             // did multiple steps, reset the e    645             // did multiple steps, reset the energy that G4Transportation will
647             // propose to not subtract the ene    646             // propose to not subtract the energy loss twice.
648             fTransportEndKineticEnergy = ekin;    647             fTransportEndKineticEnergy = ekin;
649           }                                       648           }
650                                                   649 
651           fParticleChange.ProposeTrueStepLengt    650           fParticleChange.ProposeTrueStepLength(totalStepLength);
652                                                   651 
653           // Inform G4Transportation that the     652           // Inform G4Transportation that the momentum might have changed due
654           // to scattering, even if there is n    653           // to scattering, even if there is no field.
655           fMomentumChanged = true;                654           fMomentumChanged = true;
656                                                   655 
657           return totalStepLength;                 656           return totalStepLength;
658         }                                         657         }
659       }                                           658       }
660       break;                                      659       break;
661     }                                             660     }
662   }                                               661   }
663                                                   662 
664   // If we get here, no scattering has happene    663   // If we get here, no scattering has happened.
665   return G4Transportation::AlongStepGetPhysica    664   return G4Transportation::AlongStepGetPhysicalInteractionLength(
666     track, previousStepSize, currentMinimumSte    665     track, previousStepSize, currentMinimumStep, proposedSafety, selection);
667 }                                                 666 }
668                                                   667 
669 //....oooOO0OOooo........oooOO0OOooo........oo    668 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
670                                                   669