Gabriele Cosmo
402 lines
13 KiB
Plaintext
402 lines
13 KiB
Plaintext
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// G4IntegrationDriver inline implementation
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//
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// Author: Dmitry Sorokin (CERN, Google Summer of Code 2017), 20.10.2017
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// Supervision: John Apostolakis (CERN)
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// --------------------------------------------------------------------
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#include "G4FieldUtils.hh"
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#include <CLHEP/Units/SystemOfUnits.h>
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template <class T>
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G4IntegrationDriver<T>::
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G4IntegrationDriver ( G4double hminimum, T* pStepper,
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G4int numComponents, G4int statisticsVerbose )
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: G4RKIntegrationDriver<T>(pStepper),
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fMinimumStep(hminimum),
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fVerboseLevel(statisticsVerbose)
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{
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if (numComponents != Base::GetStepper()->GetNumberOfVariables())
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{
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std::ostringstream message;
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message << "Driver's number of integrated components "
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<< numComponents
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<< " != Stepper's number of components "
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<< pStepper->GetNumberOfVariables();
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G4Exception("G4IntegrationDriver","GeomField0002",
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FatalException, message);
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}
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}
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template <class T>
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G4IntegrationDriver<T>::~G4IntegrationDriver()
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{
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#ifdef G4VERBOSE
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if (fVerboseLevel > 0)
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{
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G4cout << "G4Integration Driver Stats: "
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<< "#QuickAdvance " << fNoQuickAvanceCalls
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<< " - #AccurateAdvance " << fNoAccurateAdvanceCalls << " "
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<< "#good steps " << fNoAccurateAdvanceGoodSteps << " "
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<< "#bad steps " << fNoAccurateAdvanceBadSteps << G4endl;
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}
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#endif
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}
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template <class T>
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G4double G4IntegrationDriver<T>::AdvanceChordLimited(G4FieldTrack& track,
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G4double stepMax,
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G4double epsStep,
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G4double chordDistance)
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{
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return ChordFinderDelegate::AdvanceChordLimitedImpl(track, stepMax, epsStep,
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chordDistance);
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}
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template <class T>
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void G4IntegrationDriver<T>::OnStartTracking()
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{
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ChordFinderDelegate::ResetStepEstimate();
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}
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template <class T>
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void G4IntegrationDriver<T>::OnComputeStep(const G4FieldTrack*)
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{
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}
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template <class T>
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G4bool G4IntegrationDriver<T>::DoesReIntegrate() const
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{
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return true;
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}
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// Runge-Kutta driver with adaptive stepsize control. Integrate starting
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// values at y_current over hstep x2 with accuracy eps.
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// On output ystart is replaced by values at the end of the integration
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// interval. RightHandSide is the right-hand side of ODE system.
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// The source is similar to odeint routine from NRC p.721-722 .
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//
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template <class T>
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G4bool G4IntegrationDriver<T>::
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AccurateAdvance(G4FieldTrack& track, G4double hstep,
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G4double eps, G4double hinitial)
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{
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++fNoAccurateAdvanceCalls;
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if (hstep == 0.0)
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{
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std::ostringstream message;
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message << "Proposed step is zero; hstep = " << hstep << " !";
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G4Exception("G4IntegrationDriver::AccurateAdvance()",
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"GeomField1001", JustWarning, message);
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return true;
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}
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if (hstep < 0)
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{
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std::ostringstream message;
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message << "Invalid run condition." << G4endl
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<< "Proposed step is negative; hstep = " << hstep << "."
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<< G4endl
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<< "Requested step cannot be negative! Aborting event.";
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G4Exception("G4IntegrationDriver::AccurateAdvance()",
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"GeomField0003", EventMustBeAborted, message);
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return false;
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}
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G4double hnext, hdid;
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G4double dydx[G4FieldTrack::ncompSVEC];
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G4bool succeeded = true;
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G4double y[G4FieldTrack::ncompSVEC];
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track.DumpToArray(y);
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const G4double startCurveLength = track.GetCurveLength();
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const G4double endCurveLength = startCurveLength + hstep;
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const G4double hThreshold =
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std::min(eps * hstep, fSmallestFraction * startCurveLength);
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G4double h = hstep;
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if (hinitial > CLHEP::perMillion * hstep && hinitial < hstep)
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{
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h = hinitial;
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}
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G4double curveLength = startCurveLength;
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for (G4int nstp = 0; nstp < Base::GetMaxNoSteps(); ++nstp)
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{
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const G4ThreeVector StartPos =
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field_utils::makeVector(y, field_utils::Value3D::Position);
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Base::GetStepper()->RightHandSide(y, dydx);
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if (h > GetMinimumStep())
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{
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OneGoodStep(y, dydx, curveLength, h, eps, hdid, hnext);
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}
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else
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{
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G4FieldTrack yFldTrk('0');
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G4double dchord_step, dyerr, dyerr_len;
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yFldTrk.LoadFromArray(y, Base::GetStepper()->GetNumberOfVariables());
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yFldTrk.SetCurveLength(curveLength);
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QuickAdvance(yFldTrk, dydx, h, dchord_step, dyerr_len);
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yFldTrk.DumpToArray(y);
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if (h == 0.0)
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{
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G4Exception("G4IntegrationDriver::AccurateAdvance()",
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"GeomField0003", FatalException,
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"Integration Step became Zero!");
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}
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dyerr = dyerr_len / h;
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hdid = h;
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curveLength += hdid;
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hnext = Base::ComputeNewStepSize(dyerr / eps, h);
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}
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const G4ThreeVector EndPos =
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field_utils::makeVector(y, field_utils::Value3D::Position);
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CheckStep(EndPos, StartPos, hdid);
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// Avoid numerous small last steps
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if (h < hThreshold || curveLength >= endCurveLength)
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{
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break;
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}
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h = std::max(hnext, GetMinimumStep());
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if (curveLength + h > endCurveLength)
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{
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h = endCurveLength - curveLength;
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}
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}
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// Have we reached the end ?
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// --> a better test might be x-endCurveLength > an_epsilon
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succeeded = (curveLength >= endCurveLength);
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// If it was a "forced" last step
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track.LoadFromArray(y, Base::GetStepper()->GetNumberOfVariables());
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track.SetCurveLength(curveLength);
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return succeeded;
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}
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// Driver for one Runge-Kutta Step with monitoring of local truncation error
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// to ensure accuracy and adjust stepsize. Input are dependent variable
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// array y[0,...,5] and its derivative dydx[0,...,5] at the
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// starting value of the independent variable x . Also input are stepsize
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// to be attempted htry, and the required accuracy eps. On output y and x
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// are replaced by their new values, hdid is the stepsize that was actually
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// accomplished, and hnext is the estimated next stepsize.
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// This is similar to the function rkqs from the book:
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// Numerical Recipes in C: The Art of Scientific Computing (NRC), Second
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// Edition, by William H. Press, Saul A. Teukolsky, William T.
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// Vetterling, and Brian P. Flannery (Cambridge University Press 1992),
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// 16.2 Adaptive StepSize Control for Runge-Kutta, p. 719
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//
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template <class T>
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void G4IntegrationDriver<T>::OneGoodStep(G4double y[], // InOut
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const G4double dydx[],
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G4double& curveLength, // InOut
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G4double htry,
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G4double eps_rel_max,
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G4double& hdid, // Out
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G4double& hnext) // Out
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{
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G4double error2 = DBL_MAX;
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G4double yerr[G4FieldTrack::ncompSVEC], ytemp[G4FieldTrack::ncompSVEC];
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G4double h = htry;
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const G4int max_trials = 100;
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for (G4int iter = 0; iter < max_trials; ++iter)
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{
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Base::GetStepper()->Stepper(y, dydx, h, ytemp, yerr);
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error2 = field_utils::relativeError2(y, yerr, std::max(h, fMinimumStep),
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eps_rel_max);
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if (error2 <= 1.0)
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{
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break;
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}
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h = Base::ShrinkStepSize2(h, error2);
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G4double xnew = curveLength + h;
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if(xnew == curveLength)
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{
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std::ostringstream message;
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message << "Stepsize underflow in Stepper !" << G4endl
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<< "- Step's start x=" << curveLength
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<< " and end x= " << xnew
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<< " are equal !! " << G4endl
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<< " Due to step-size= " << h
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<< ". Note that input step was " << htry;
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G4Exception("G4IntegrationDriver::OneGoodStep()",
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"GeomField1001", JustWarning, message);
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break;
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}
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}
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hnext = Base::GrowStepSize2(h, error2);
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curveLength += (hdid = h);
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field_utils::copy(y, ytemp, Base::GetStepper()->GetNumberOfVariables());
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}
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template <class T>
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G4bool G4IntegrationDriver<T>::QuickAdvance(G4FieldTrack& track, // INOUT
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const G4double dydx[],
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G4double hstep,
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G4double& dchord_step,
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G4double& dyerr)
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{
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++fNoQuickAvanceCalls;
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G4double yIn[G4FieldTrack::ncompSVEC],
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yOut[G4FieldTrack::ncompSVEC],
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yError[G4FieldTrack::ncompSVEC];
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track.DumpToArray(yIn);
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Base::GetStepper()->Stepper(yIn, dydx, hstep, yOut, yError);
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dchord_step = Base::GetStepper()->DistChord();
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dyerr = field_utils::absoluteError(yOut, yError, hstep);
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track.LoadFromArray(yOut, Base::GetStepper()->GetNumberOfVariables());
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track.SetCurveLength(track.GetCurveLength() + hstep);
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return true;
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}
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template <class T>
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void G4IntegrationDriver<T>::CheckStep(const G4ThreeVector& posIn,
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const G4ThreeVector& posOut,
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G4double hdid)
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{
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const G4double endPointDist = (posOut - posIn).mag();
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if (endPointDist >= hdid * (1. + CLHEP::perMillion))
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{
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++fNoAccurateAdvanceBadSteps;
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#ifdef G4DEBUG_FIELD
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// Issue a warning only for gross differences -
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// we understand how small difference occur.
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if (endPointDist >= hdid * (1. + perThousand))
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{
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G4Exception("G4IntegrationDriver::CheckStep()",
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"GeomField1002", JustWarning,
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"endPointDist >= hdid!");
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}
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#endif
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}
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else
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{
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++fNoAccurateAdvanceGoodSteps;
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}
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}
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template <class T>
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inline G4double G4IntegrationDriver<T>::GetMinimumStep() const
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{
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return fMinimumStep;
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}
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template <class T>
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void G4IntegrationDriver<T>::SetMinimumStep(G4double minimumStepLength)
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{
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fMinimumStep = minimumStepLength;
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}
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template <class T>
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G4int G4IntegrationDriver<T>::GetVerboseLevel() const
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{
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return fVerboseLevel;
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}
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template <class T>
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void G4IntegrationDriver<T>::SetVerboseLevel(G4int newLevel)
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{
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fVerboseLevel = newLevel;
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}
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template <class T>
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G4double G4IntegrationDriver<T>::GetSmallestFraction() const
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{
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return fSmallestFraction;
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}
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template <class T>
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void G4IntegrationDriver<T>::SetSmallestFraction(G4double newFraction)
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{
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if (newFraction > 1.e-16 && newFraction < 1e-8)
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{
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fSmallestFraction = newFraction;
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}
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else
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{
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std::ostringstream message;
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message << "Smallest Fraction not changed. " << G4endl
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<< " Proposed value was " << newFraction << G4endl
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<< " Value must be between 1.e-8 and 1.e-16";
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G4Exception("G4IntegrationDriver::SetSmallestFraction()",
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"GeomField1001", JustWarning, message);
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}
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}
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template <class T>
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void G4IntegrationDriver<T>::IncrementQuickAdvanceCalls()
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{
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++fNoQuickAvanceCalls;
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}
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template <class T>
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void G4IntegrationDriver<T>::StreamInfo( std::ostream& os ) const
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{
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// Write out the parameters / state of the driver
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os << "State of G4IntegrationDriver: " << std::endl;
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os << "--Base state (G4RKIntegrationDriver): " << std::endl;
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Base::StreamInfo( os );
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os << "--Own state (G4IntegrationDriver<>): " << std::endl;
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os << " fMinimumStep = " << fMinimumStep << std::endl;
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os << " Smallest Fraction = " << fSmallestFraction << std::endl;
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os << " verbose level = " << fVerboseLevel << std::endl;
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os << " Reintegrates = " << DoesReIntegrate() << std::endl;
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os << "--Chord Finder Delegate state: " << std::endl;
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ChordFinderDelegate::StreamDelegateInfo( os );
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}
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