Gabriele Cosmo
453 lines
16 KiB
Plaintext
453 lines
16 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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//
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//
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// class G4InterpolationDriver
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//
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// Class description:
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//
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// Driver class which uses Runge-Kutta stepper with interpolation property
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// to integrate track with error control
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// History:
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// - Created. D.Sorokin
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// --------------------------------------------------------------------
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#include "G4FieldUtils.hh"
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#include "G4LineSection.hh"
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template <class T>
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G4InterpolationDriver<T>::
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G4InterpolationDriver ( 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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fNoAdvanceChordLimitedCalls(0),
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fNoAdvanceChordLimitedSmallSteps(0),
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fNoAdvanceChordLimitedFullSteps(0),
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fNoAccurateAdvanceCalls(0),
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fNoAccurateAdvanceBadSteps(0),
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fNoAccurateAdvanceGoodSteps(0),
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fMaxTrials(0)
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{
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fIntegrationInterval = {DBL_MAX, -DBL_MAX};
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fhnext = 0;
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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("G4InterpolationDriver","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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G4InterpolationDriver<T>::~G4InterpolationDriver()
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{
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#ifdef G4VERBOSE
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if (fVerboseLevel > 0)
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G4cout << "G4Integration Driver Stats:" << G4endl
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<< "#AdvanceChordLimited " << fNoAdvanceChordLimitedCalls
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<< " - #full steps " << fNoAdvanceChordLimitedFullSteps << " "
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<< "#small steps " << fNoAdvanceChordLimitedSmallSteps << G4endl
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<< "#AccurateAdvance " << fNoAccurateAdvanceCalls << G4endl
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<< "#maxtrials " << fMaxTrials << G4endl;
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#endif
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}
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template <class T>
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G4double G4InterpolationDriver<T>::
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AdvanceChordLimited(G4FieldTrack& track,
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G4double hstep,
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G4double eps,
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G4double chordDistance)
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{
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++fNoAdvanceChordLimitedCalls;
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if (fhnext == 0) fhnext = hstep;
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const G4double curveLength = track.GetCurveLength();
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State y;
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track.DumpToArray(y);
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//field_utils::print(y);
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// update integration inverval
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//const G4double interval = fIntegrationInterval.second - fIntegrationInterval.first;
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if (curveLength < fIntegrationInterval.first || curveLength >= fIntegrationInterval.second - CLHEP::perThousand)
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//if (curveLength < fIntegrationInterval.first || curveLength + hstep > fIntegrationInterval.second)
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{
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G4double hdid;
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State dydx;
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Base::GetStepper()->RightHandSide(y, dydx);
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OneGoodStep(y, dydx, fhnext, eps, hdid, fhnext);
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fIntegrationInterval = { curveLength, curveLength + hdid };
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//G4cout << "AdvanceChordLimited init interval: " << fIntegrationInterval.first << " " << fIntegrationInterval.second << G4endl;
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Base::GetStepper()->SetupInterpolation();
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}
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G4double hmax;
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const G4double canAdvance = fIntegrationInterval.second - curveLength;
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if (canAdvance < hstep) {
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hmax = canAdvance;
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++fNoAdvanceChordLimitedSmallSteps;
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} else {
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hmax = hstep;
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++fNoAdvanceChordLimitedFullSteps;
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}
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//const G4double hmax = std::min(fIntegrationInterval.second - curveLength, hstep);
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//const G4double hdid = FindNextChord(y, curveLength, hmax, chordDistance);
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const G4double hdid = BinsearchChord(y, curveLength, hmax, chordDistance);
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//check results
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/*{
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const G4double interval = fIntegrationInterval.second - fIntegrationInterval.first;
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const G4ThreeVector x0 = track.GetPosition();
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State y0;
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Base::GetStepper()->Interpolate(curveLength / interval, y0);
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const G4ThreeVector x0_interp = field_utils::makeVector(y0, field_utils::Value3D::Position);
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//G4cout <<"curveLength " <<curveLength <<" x0_diff " << (x0 - x0_interp).mag() << G4endl;
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const G4ThreeVector x1 = field_utils::makeVector(y, field_utils::Value3D::Position);
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//G4cout << "hdid " << hdid << " delta_x " << (x1 - x0).mag() << G4endl;
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}*/
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track.LoadFromArray(y, Base::GetStepper()->GetNumberOfVariables());
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track.SetCurveLength(curveLength + hdid);
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//field_utils::print(y);
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//G4cout << "AdvanceChordLimited hmax: " << hmax << " hstep: " << hstep <<" hdid: " << hdid << G4endl;
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return hdid;
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}
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template <class T>
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G4double G4InterpolationDriver<T>::FindNextChord(State& y,
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G4double hstart,
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G4double hmax,
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G4double chordDistance)
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{
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const G4double interval = fIntegrationInterval.second - fIntegrationInterval.first;
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//G4cout << "len(interval) = " << interval << G4endl;
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//G4cout << "FindNextChord yOrigin ";
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//field_utils::print(y);
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State ytemp;
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const G4double tauStart = (hstart - fIntegrationInterval.first) / interval;
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Base::GetStepper()->Interpolate(tauStart, ytemp);
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//G4cout << "FindNextChord yInterp ";
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//field_utils::print(ytemp);
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//G4cout << "FindNextChord hmax " << hmax << G4endl;
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// check start point
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if (fChordStepEstimate == 0) fChordStepEstimate = DBL_MAX;
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G4double hstep = std::min(hmax, 0.98 * fChordStepEstimate); // TODO: use dsigita calculated analitically!
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const G4ThreeVector start = field_utils::makeVector(y, field_utils::Value3D::Position);
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G4int i = 0;
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for (i = 0; i < 100; ++i)
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{
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//G4cout << "hstep = " << hstep << G4endl;
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G4double deltaTau = hstep / interval;
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G4double tau = tauStart + deltaTau;
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G4double tauMid = tauStart + 0.5 * deltaTau;
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assert(tau > tauStart && tau <= 1);
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//G4cout << "tau: " << tau << " ";
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Base::GetStepper()->Interpolate(tauMid, y);
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const G4ThreeVector mid = field_utils::makeVector(y, field_utils::Value3D::Position);
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//G4cout << "mid: " << mid << " ";
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Base::GetStepper()->Interpolate(tau, y);
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const G4ThreeVector end = field_utils::makeVector(y, field_utils::Value3D::Position);
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//G4cout << "end: " << end << G4endl;
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const G4double distance = G4LineSection::Distline(mid, start, end);
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//G4cout << "FindNextChord tau " << tau << " hstep " << hstep << " distance " << distance << " chordDistance " << chordDistance << G4endl;
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if (distance <= chordDistance)
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{
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fMaxTrials = std::max(fMaxTrials, i);
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return hstep;
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}
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//crop step size
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fChordStepEstimate = hstep * std::sqrt(chordDistance / distance);
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hstep = 0.98 * fChordStepEstimate;
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}
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G4Exception("G4InterpolationDriver::FindNextChord()",
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"GeomField1001", FatalException, "cannot converge");
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return hstep;
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}
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template <class T>
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G4double G4InterpolationDriver<T>::BinsearchChord(State& y,
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G4double hstart,
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G4double hmaximum,
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G4double chordDistance)
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{
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const G4double interval = fIntegrationInterval.second - fIntegrationInterval.first;
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const G4double tauStart = (hstart - fIntegrationInterval.first) / interval;
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const G4ThreeVector start = field_utils::makeVector(y, field_utils::Value3D::Position);
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auto calcChordDistance = [&](G4double hstep)
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{
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using namespace field_utils;
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const G4double deltaTau = hstep / interval;
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const G4double tau = tauStart + deltaTau;
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const G4double tauMid = tauStart + 0.5 * deltaTau;
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assert(tau > tauStart && tau <= 1);
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//G4cout << "tau: " << tau << " ";
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Base::GetStepper()->Interpolate(tauMid, y);
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const G4ThreeVector mid = makeVector(y, Value3D::Position);
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//G4cout << "mid: " << mid << " ";
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Base::GetStepper()->Interpolate(tau, y);
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const G4ThreeVector end = makeVector(y, Value3D::Position);
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//G4cout << "end: " << end << G4endl;
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return G4LineSection::Distline(mid, start, end);
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};
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if (calcChordDistance(hmaximum) < chordDistance)
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{
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fChordStepEstimate = std::max(hmaximum, fChordStepEstimate);
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return hmaximum;
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}
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G4double hmax = hmaximum;
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G4double hmin = 0;
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G4double hstep = fChordStepEstimate ?
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std::min(fChordStepEstimate, hmax) : 0.5 * (hmax + hmin);
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G4double distance;
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for (G4int i = 1; i < 100; ++i)
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{
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distance = calcChordDistance(hstep);
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//G4cout << "i " << i << " hmin " << hmin << " hstep " << hstep << " hmax " << hmax <<" ";
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//G4cout << "disntace " << distance << " chordDistance " << chordDistance << G4endl;
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if (distance <= chordDistance && distance > 0.9 * chordDistance)
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{
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fChordStepEstimate = hstep;
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fMaxTrials = std::max(fMaxTrials, i);
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return hstep;
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}
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if (distance < chordDistance)
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{
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hmin = hstep;
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} else // distance > chordDistance
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{
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hmax = hstep;
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}
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hstep = 0.5 * (hmax + hmin);
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//hstep = 0.5 * (hmax + hmin);//std::min(hstep * std::sqrt(chordDistance / distance), hmax);
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}
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G4cout << "distance " << distance << " requested " << chordDistance << " "
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<< "step " << hstep << G4endl;
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G4Exception("G4InterpolationDriver::FindNextChord()",
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"GeomField1001", FatalException, "cannot converge");
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return hstep;
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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 G4InterpolationDriver<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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//G4cout << "AA hstep " << hstep << G4endl;
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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("G4InterpolationDriver::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 << "." << G4endl
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<< "Requested step cannot be negative! Aborting event.";
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G4Exception("G4InterpolationDriver::AccurateAdvance()",
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"GeomField0003", EventMustBeAborted, message);
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return false;
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}
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const G4double curveLength = track.GetCurveLength();
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const G4double curveLengthEnd = curveLength + hstep;
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assert(curveLength >= fIntegrationInterval.first && curveLengthEnd <= fIntegrationInterval.second);
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State y;
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const G4double tau = (curveLengthEnd - fIntegrationInterval.first) / (fIntegrationInterval.second - fIntegrationInterval.first);
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Base::GetStepper()->Interpolate(tau, y);
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track.LoadFromArray(y, Base::GetStepper()->GetNumberOfVariables());
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track.SetCurveLength(curveLengthEnd);
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return true;
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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 G4InterpolationDriver<T>::OneGoodStep(const G4double y[], // InOut
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const G4double dydx[],
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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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//G4cout << "htry: " << htry << G4endl;
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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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{
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tot_no_trials++;
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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), 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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}
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hnext = Base::GrowStepSize2(h, error2);
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hdid = h;
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//G4cout << "hdid: " << hdid << G4endl;
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}
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template <class T>
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void G4InterpolationDriver<T>::
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CheckStep( const G4ThreeVector& posIn,
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const G4ThreeVector& posOut, 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("G4InterpolationDriver::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 G4InterpolationDriver<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 G4InterpolationDriver<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 G4InterpolationDriver<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 G4InterpolationDriver<T>::SetVerboseLevel(G4int newLevel)
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{
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fVerboseLevel = newLevel;
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}
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