include/Geant4/G4QSSDriver.icc

0001 //
0002 // ********************************************************************
0003 // * License and Disclaimer                                           *
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0024 // ********************************************************************
0025 //
0026 // --------------------------------------------------------------------
0027
0028 template <class T>
0029 G4QSSDriver<T>::G4QSSDriver(T* pStepper) : G4InterpolationDriver<T, true>(0, pStepper)
0030 {
0031   // TODO: Remove additional stepper instances - should be a separate Driver class
0032   this->fSteppers.resize(1);
0033 }
0034
0035 template <class T>
0036 void G4QSSDriver<T>::OnStartTracking()
0037 {
0038   Base::OnStartTracking();
0039   if (! initializedOnFirstRun) {
0040     // this->SetPrecision( G4QSSMessenger::instance()->dQRel, G4QSSMessenger::instance()->dQMin);
0041
0042     G4double dqRel = G4QSSMessenger::instance()->dQRel;
0043     G4double dQMin = G4QSSMessenger::instance()->dQMin;
0044     if (dqRel == 0) {
0045       dqRel = 0.001;
0046     }
0047     if (dQMin == 0) {
0048       dQMin = 0.0001;
0049     }
0050     this->SetPrecision(dqRel, dQMin);
0051
0052     initializedOnFirstRun = true;
0053   }
0054 }
0055
0056 template <class T>
0057 void G4QSSDriver<T>::SetPrecision(G4double dq_rel, G4double dq_min)
0058 {
0059   G4cout << "Setting QSS precision parameters: "
0060          << "dQRel = " << dq_rel << " - "
0061          << "dQMin = " << dq_min << G4endl;
0062
0063   for (const auto& item : this->fSteppers) {
0064     item.stepper->SetPrecision(dq_rel, dq_min);
0065   }
0066 }
0067
0068 template <class T>
0069 G4double G4QSSDriver<T>::AdvanceChordLimited(
0070   G4FieldTrack& track, G4double hstep, G4double epsStep, G4double chordDistance)
0071 {
0072   // For now, just extract functionality that we don't use from G4InterpolationDriver
0073   // We should probably end up making  a custom G4QSSDriver separated from it
0074   ++this->fTotalStepsForTrack;
0075   this->fLastStepper = this->fSteppers.begin();
0076
0077   const G4double preCurveLength = track.GetCurveLength();
0078   G4double postCurveLength = preCurveLength;
0079   auto it = this->fSteppers.begin();
0080
0081   it->stepper->reset(const_cast<const G4FieldTrack*>(&track));
0082
0083   field_utils::State yBegin, y;
0084   track.DumpToArray(yBegin);
0085   track.DumpToArray(y);
0086
0087   G4double hdid = OneGoodStep(it, y, this->fdydx, hstep, epsStep, preCurveLength, &track);
0088   postCurveLength += hdid;
0089
0090   G4double dChordStep = this->DistChord(yBegin, preCurveLength, y, postCurveLength);
0091
0092   // update chord step estimate
0093   hdid = this->FindNextChord(
0094     yBegin, preCurveLength, y, postCurveLength, dChordStep, chordDistance);
0095
0096   track.LoadFromArray(y, this->fSteppers[0].stepper->GetNumberOfVariables());
0097   track.SetCurveLength(preCurveLength + hdid);
0098
0099   return hdid;
0100 }
0101
0102 template <class T>
0103 G4double G4QSSDriver<T>::OneGoodStep(typename G4InterpolationDriver<T, true>::StepperIterator it,
0104   field_utils::State& y, field_utils::State& dydx, G4double& hstep, G4double /*epsStep*/,
0105   G4double curveLength, G4FieldTrack* /*track*/)
0106 {
0107   G4double yerr[G4FieldTrack::ncompSVEC], ytemp[G4FieldTrack::ncompSVEC];
0108   it->stepper->Stepper(y, dydx, hstep, ytemp, yerr);
0109   G4double h = it->stepper->GetLastStepLength();
0110
0111   // set interpolation interval
0112   it->begin = curveLength;
0113   it->end = curveLength + h;
0114   it->inverseLength = 1. / h;
0115
0116   field_utils::copy(y, ytemp);
0117
0118   return h;
0119 }