Gabriele Cosmo
461 lines
14 KiB
Plaintext
461 lines
14 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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//
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// $Id: G4FSALIntegrationDriver.icc 107495 2017-11-16 13:51:06Z gcosmo $
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//
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//
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// class G4FSALIntegrationDriver
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//
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// Class description:
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//
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// Driver class which controls the integration error of a
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// Runge-Kutta stepper with a FSAL property
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// History:
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// - Created. D.Sorokin
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// --------------------------------------------------------------------
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#include "globals.hh"
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#include "G4GeometryTolerance.hh"
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#include "G4FieldTrack.hh"
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#include "G4FieldUtils.hh"
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#include <cassert>
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template <class T>
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G4FSALIntegrationDriver<T>::G4FSALIntegrationDriver (
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G4double hminimum,
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T* pStepper,
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G4int numComponents,
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G4int statisticsVerbose)
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: fSmallestFraction(1e-12),
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fNoTotalSteps(0),
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fNoBadSteps(0),
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fNoGoodSteps(0),
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fVerboseLevel(statisticsVerbose),
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fNoQuickAvanceCalls(0)
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{
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if (numComponents != pStepper->GetNumberOfVariables()) {
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std::ostringstream message;
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message << "Driver's number of integrated components " << numComponents
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<< " != Stepper's number of components " << pStepper->GetNumberOfVariables();
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G4Exception("G4FSALIntegrationDriver","001", FatalException, message);
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}
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RenewStepperAndAdjust(pStepper);
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fMinimumStep = hminimum;
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fMaxNoSteps = fMaxStepBase / pIntStepper->IntegratorOrder();
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}
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template <class T>
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G4FSALIntegrationDriver<T>::~G4FSALIntegrationDriver()
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{
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if( fVerboseLevel > 0 )
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G4cout << "G4FSALIntegration Driver Stats: "
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<< "#QuickAdvance " << fNoQuickAvanceCalls
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<< " #AccurateAdvance " << fNoTotalSteps << G4endl;
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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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template <class T>
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G4bool G4FSALIntegrationDriver<T>::AccurateAdvance(
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G4FieldTrack& track,
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G4double hstep,
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G4double eps,
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G4double hinitial)
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{
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if (hstep < GetMinimumStep()) {
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G4double dchord_step = 0, dyerr = 0;
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G4double dydx[G4FieldTrack::ncompSVEC];
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GetDerivatives(track, dydx);
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return QuickAdvance(track, dydx, hstep, dchord_step, dyerr);
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}
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G4bool succeeded = false;
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G4double hnext, hdid;
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G4double y[G4FieldTrack::ncompSVEC], dydx[G4FieldTrack::ncompSVEC];
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track.DumpToArray(y);
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// hstep somtimes is too small. No need to add large curveLength.
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G4double curveLength = 0;
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G4double endCurveLength = hstep;
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G4double h = hstep;
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if (hinitial > perMillion * hstep && hinitial < hstep) {
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h = hinitial;
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}
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pIntStepper->RightHandSide(y, dydx);
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for (G4int iter = 0; iter < fMaxNoSteps; ++iter) {
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const G4ThreeVector StartPos =
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field_utils::makeVector(y, field_utils::Value3D::Position);
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OneGoodStep(y, dydx, curveLength, h, eps, hdid, hnext);
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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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G4double restCurveLength = endCurveLength - curveLength;
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if (restCurveLength < GetSmallestFraction() * hstep) {
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succeeded = true;
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break;
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}
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h = std::min(hnext, restCurveLength);
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}
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if (succeeded) {
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track.LoadFromArray(y, pIntStepper->GetNumberOfVariables());
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track.SetCurveLength(track.GetCurveLength() + curveLength);
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}
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return succeeded;
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}
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// Step failed; compute the size of retrial Step.
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template <class T>
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G4double G4FSALIntegrationDriver<T>::ShrinkStepSize(G4double h, G4double error) const
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{
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if (error > errorConstraintShrink) {
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return max_stepping_decrease * h;
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}
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return GetSafety() * h * std::pow(error, GetPshrnk());
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}
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// Compute size of next Step
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template<class T>
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G4double G4FSALIntegrationDriver<T>::GrowStepSize(G4double h, G4double error) const
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{
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if (error < errorConstraintGrow) {
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return max_stepping_increase * h;
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}
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return GetSafety() * h * std::pow(error, GetPgrow());
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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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template <class T>
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void G4FSALIntegrationDriver<T>::OneGoodStep(
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G4double y[],
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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 error = DBL_MAX;
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G4double yError[G4FieldTrack::ncompSVEC],
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yOut[G4FieldTrack::ncompSVEC],
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dydxOut[G4FieldTrack::ncompSVEC];
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// Set stepsize to the initial trial value
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G4double hstep = htry;
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static G4ThreadLocal G4int tot_no_trials = 0;
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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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++tot_no_trials;
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pIntStepper->Stepper(y, dydx, hstep, yOut, yError, dydxOut);
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error = field_utils::relativeError(y, yError, hstep, eps_rel_max);
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// Step succeeded.
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if (error <= 1) {
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break;
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}
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hstep = ShrinkStepSize(hstep, error);
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}
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hnext = GrowStepSize(hstep, error);
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curveLength += (hdid = hstep);
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for(G4int k = 0; k < pIntStepper->GetNumberOfVariables(); ++k) {
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y[k] = yOut[k];
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dydx[k] = dydxOut[k];
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}
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}
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template <class T>
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G4bool G4FSALIntegrationDriver<T>::QuickAdvance(
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G4FieldTrack& fieldTrack,
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const G4double dydxIn[],
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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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if (hstep == 0) {
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std::ostringstream message;
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message << "Proposed step is zero; hstep = " << hstep << " !";
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G4Exception("G4FSALIntegrationDriver ::QuickAdvance()",
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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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std::ostringstream message;
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message << "Invalid run condition." << G4endl
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<< "Proposed step is negative; hstep = " << hstep << "." << G4endl
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<< "Requested step cannot be negative! Aborting event.";
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G4Exception("G4FSALIntegrationDriver ::QuickAdvance()",
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"GeomField0003", EventMustBeAborted, message);
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return false;
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}
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G4double yError[G4FieldTrack::ncompSVEC],
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yIn[G4FieldTrack::ncompSVEC],
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yOut[G4FieldTrack::ncompSVEC],
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dydxOut[G4FieldTrack::ncompSVEC];
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fieldTrack.DumpToArray(yIn);
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pIntStepper->Stepper(yIn, dydxIn, hstep, yOut, yError, dydxOut);
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dchord_step = pIntStepper->DistChord();
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fieldTrack.LoadFromArray(yOut, pIntStepper->GetNumberOfVariables());
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fieldTrack.SetCurveLength(fieldTrack.GetCurveLength() + hstep);
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dyerr = field_utils::relativeError(yOut, yError, hstep) * hstep;
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return true;
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}
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template <class T>
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G4double G4FSALIntegrationDriver<T>::ComputeNewStepSize(
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G4double errMaxNorm, // max error (normalised)
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G4double hstepCurrent) // current step size
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{
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if (errMaxNorm > 1) {
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return ShrinkStepSize(hstepCurrent, errMaxNorm);
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} else if(errMaxNorm >= 0) {
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return GrowStepSize(hstepCurrent, errMaxNorm);
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}
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G4Exception("G4FSALIntegrationDriver::ConputeNewStepSize", "Field002",
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FatalException, "error is negative");
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return max_stepping_increase * hstepCurrent;
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::SetSmallestFraction(G4double newFraction)
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{
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if( newFraction > 1.e-16 && newFraction < 1e-8 ) {
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fSmallestFraction = newFraction;
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} else {
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G4cerr << "Warning: SmallestFraction 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" << G4endl;
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}
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::GetDerivatives(
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const G4FieldTrack& track, G4double dydx[]) const
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{
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G4double y[G4FieldTrack::ncompSVEC];
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track.DumpToArray(y);
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pIntStepper->RightHandSide(y, dydx);
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::CheckStep(
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const G4ThreeVector& posIn, const G4ThreeVector& posOut, G4double hdid)
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{
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++fNoTotalSteps;
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const G4double endPointDist = (posOut - posIn).mag();
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if (endPointDist >= hdid * (1. + perMillion)) {
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++fNoBadSteps;
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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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G4cout << "WARNING: endPointDist >= hdid!" << G4endl;
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}
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} else {
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++fNoGoodSteps;
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}
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::UpdateErrorConstraints()
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{
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errorConstraintShrink = std::pow(
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max_stepping_decrease / GetSafety(), 1. / GetPshrnk());
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errorConstraintGrow = std::pow(
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max_stepping_increase / GetSafety(), 1. / GetPgrow());
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}
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template <class T>
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inline G4double G4FSALIntegrationDriver<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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inline G4double G4FSALIntegrationDriver<T>::GetSafety() const
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{
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return safety;
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}
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template <class T>
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inline G4double G4FSALIntegrationDriver<T>::GetPshrnk() const
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{
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return pshrnk;
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}
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template <class T>
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G4double G4FSALIntegrationDriver<T>::GetPgrow() const
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{
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return pgrow;
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}
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template <class T>
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void G4FSALIntegrationDriver<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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void G4FSALIntegrationDriver<T>::ReSetParameters(G4double new_safety)
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{
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safety = new_safety;
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pshrnk = -1.0 / pIntStepper->IntegratorOrder();
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pgrow = -1.0 / (1.0 + pIntStepper->IntegratorOrder());
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UpdateErrorConstraints();
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::SetSafety(G4double val)
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{
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safety = val;
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UpdateErrorConstraints();
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::RenewStepperAndAdjust(T* stepper)
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{
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pIntStepper = stepper;
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ReSetParameters();
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}
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template <class T>
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const T* G4FSALIntegrationDriver<T>::GetStepperOfPreciseType() const
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{
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return pIntStepper;
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}
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template <class T>
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T* G4FSALIntegrationDriver<T>::GetStepperOfPreciseType()
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{
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return pIntStepper;
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}
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template <class T>
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const G4MagIntegratorStepper* G4FSALIntegrationDriver<T>::GetStepper() const
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{
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return nullptr; // pIntStepper;
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// It can only return 'pIntStepper' if it is a compatible type
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}
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template <class T>
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G4MagIntegratorStepper* G4FSALIntegrationDriver<T>::GetStepper()
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{
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return nullptr;
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// It can only return 'pIntStepper' if it is a compatible type
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}
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template <class T>
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G4int G4FSALIntegrationDriver<T>::GetMaxNoSteps() const
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{
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return fMaxNoSteps;
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::SetMaxNoSteps(G4int val)
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{
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fMaxNoSteps = val;
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}
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template <class T>
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G4int G4FSALIntegrationDriver<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 G4FSALIntegrationDriver<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 G4FSALIntegrationDriver<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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G4EquationOfMotion* G4FSALIntegrationDriver<T>::GetEquationOfMotion()
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{
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return pIntStepper->GetEquationOfMotion();
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}
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template <class T>
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void G4FSALIntegrationDriver<T>::SetEquationOfMotion(G4EquationOfMotion* equation)
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{
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pIntStepper->SetEquationOfMotion(equation);
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}
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