| [831] | 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | //
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| [850] | 27 | // $Id: G4ChordFinder.cc,v 1.49 2008/07/15 14:02:06 japost Exp $
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| 28 | // GEANT4 tag $Name: HEAD $
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| [831] | 29 | //
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| 30 | //
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| 31 | // 25.02.97 John Apostolakis, design and implimentation
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| 32 | // 05.03.97 V. Grichine , style modification
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| 33 | // -------------------------------------------------------------------
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| 34 |
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| 35 | #include "G4ChordFinder.hh"
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| 36 | #include "G4MagneticField.hh"
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| 37 | #include "G4Mag_UsualEqRhs.hh"
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| 38 | #include "G4ClassicalRK4.hh"
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| 39 |
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| 40 | #include <iomanip>
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| 41 |
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| 42 | // ..........................................................................
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| 43 |
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| 44 | G4ChordFinder::G4ChordFinder(G4MagInt_Driver* pIntegrationDriver)
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| 45 | : fDefaultDeltaChord( 0.25 * mm ),
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| 46 | fDeltaChord( fDefaultDeltaChord ),
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| 47 | fAllocatedStepper(false),
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| 48 | fEquation(0),
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| 49 | fDriversStepper(0),
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| 50 | fFirstFraction(0.999), fFractionLast(1.00), fFractionNextEstimate(0.98),
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| 51 | fMultipleRadius(15.0),
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| 52 | fTotalNoTrials_FNC(0), fNoCalls_FNC(0), fmaxTrials_FNC(0),
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| 53 | fStatsVerbose(0)
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| 54 | {
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| 55 | // Simple constructor which does not create equation, ..
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| 56 | // fDeltaChord= fDefaultDeltaChord;
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| 57 | fIntgrDriver= pIntegrationDriver;
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| 58 | fAllocatedStepper= false;
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| 59 | fLastStepEstimate_Unconstrained = DBL_MAX; // Should move q, p to
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| 60 |
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| 61 | SetFractions_Last_Next( fFractionLast, fFractionNextEstimate);
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| 62 | // check the values and set the other parameters
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| 63 | }
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| 64 |
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| 65 | // ..........................................................................
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| 66 |
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| 67 | G4ChordFinder::G4ChordFinder( G4MagneticField* theMagField,
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| 68 | G4double stepMinimum,
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| 69 | G4MagIntegratorStepper* pItsStepper )
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| 70 | : fDefaultDeltaChord( 0.25 * mm ),
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| 71 | fDeltaChord( fDefaultDeltaChord ),
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| 72 | fAllocatedStepper(false),
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| 73 | fEquation(0),
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| 74 | fDriversStepper(0),
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| 75 | fFirstFraction(0.999), fFractionLast(1.00), fFractionNextEstimate(0.98),
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| 76 | fMultipleRadius(15.0),
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| 77 | fTotalNoTrials_FNC(0), fNoCalls_FNC(0), fmaxTrials_FNC(0),
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| 78 | fStatsVerbose(0)
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| 79 | {
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| 80 | // Construct the Chord Finder
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| 81 | // by creating in inverse order the Driver, the Stepper and EqRhs ...
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| 82 | G4Mag_EqRhs *pEquation = new G4Mag_UsualEqRhs(theMagField);
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| 83 | fEquation = pEquation;
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| 84 | fLastStepEstimate_Unconstrained = DBL_MAX; // Should move q, p to
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| 85 | // G4FieldTrack ??
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| 86 |
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| 87 | SetFractions_Last_Next( fFractionLast, fFractionNextEstimate);
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| 88 | // check the values and set the other parameters
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| 89 |
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| 90 | // --->> Charge Q = 0
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| 91 | // --->> Momentum P = 1 NOMINAL VALUES !!!!!!!!!!!!!!!!!!
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| 92 |
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| 93 | if( pItsStepper == 0 )
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| 94 | {
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| 95 | pItsStepper = fDriversStepper = new G4ClassicalRK4(pEquation);
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| 96 | fAllocatedStepper= true;
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| 97 | }
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| 98 | else
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| 99 | {
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| 100 | fAllocatedStepper= false;
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| 101 | }
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| 102 | fIntgrDriver = new G4MagInt_Driver(stepMinimum, pItsStepper,
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| 103 | pItsStepper->GetNumberOfVariables() );
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| 104 | }
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| 105 |
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| 106 | // ......................................................................
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| 107 |
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| 108 | void
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| 109 | G4ChordFinder::SetFractions_Last_Next( G4double fractLast, G4double fractNext )
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| 110 | {
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| 111 | // Use -1.0 as request for Default.
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| 112 | if( fractLast == -1.0 ) fractLast = 1.0; // 0.9;
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| 113 | if( fractNext == -1.0 ) fractNext = 0.98; // 0.9;
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| 114 |
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| 115 | // fFirstFraction = 0.999; // Orig 0.999 A safe value, range: ~ 0.95 - 0.999
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| 116 | // fMultipleRadius = 15.0; // For later use, range: ~ 2 - 20
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| 117 |
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| 118 | if( fStatsVerbose ) {
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| 119 | G4cout << " ChordFnd> Trying to set fractions: "
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| 120 | << " first " << fFirstFraction
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| 121 | << " last " << fractLast
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| 122 | << " next " << fractNext
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| 123 | << " and multiple " << fMultipleRadius
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| 124 | << G4endl;
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| 125 | }
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| 126 |
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| 127 | if( (fractLast > 0.0) && (fractLast <=1.0) )
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| 128 | { fFractionLast= fractLast; }
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| 129 | else
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| 130 | G4cerr << "G4ChordFinder:: SetFractions_Last_Next: Invalid "
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| 131 | << " fraction Last = " << fractLast
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| 132 | << " must be 0 < fractionLast <= 1 " << G4endl;
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| 133 | if( (fractNext > 0.0) && (fractNext <1.0) )
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| 134 | { fFractionNextEstimate = fractNext; }
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| 135 | else
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| 136 | G4cerr << "G4ChordFinder:: SetFractions_Last_Next: Invalid "
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| 137 | << " fraction Next = " << fractNext
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| 138 | << " must be 0 < fractionNext < 1 " << G4endl;
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| 139 | }
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| 140 |
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| 141 | // ......................................................................
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| 142 |
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| 143 | G4ChordFinder::~G4ChordFinder()
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| 144 | {
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| 145 | delete fEquation; // fIntgrDriver->pIntStepper->theEquation_Rhs;
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| 146 | if( fAllocatedStepper)
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| 147 | {
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| 148 | delete fDriversStepper;
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| 149 | } // fIntgrDriver->pIntStepper;}
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| 150 | delete fIntgrDriver;
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| 151 |
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| 152 | if( fStatsVerbose ) { PrintStatistics(); }
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| 153 | }
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| 154 |
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| 155 | void
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| 156 | G4ChordFinder::PrintStatistics()
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| 157 | {
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| 158 | // Print Statistics
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| 159 | G4cout << "G4ChordFinder statistics report: " << G4endl;
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| 160 | G4cout
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| 161 | << " No trials: " << fTotalNoTrials_FNC
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| 162 | << " No Calls: " << fNoCalls_FNC
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| 163 | << " Max-trial: " << fmaxTrials_FNC
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| 164 | << G4endl;
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| 165 | G4cout
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| 166 | << " Parameters: "
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| 167 | << " fFirstFraction " << fFirstFraction
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| 168 | << " fFractionLast " << fFractionLast
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| 169 | << " fFractionNextEstimate " << fFractionNextEstimate
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| 170 | << G4endl;
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| 171 | }
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| 172 |
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| 173 | // ......................................................................
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| 174 |
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| 175 | G4double
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| 176 | G4ChordFinder::AdvanceChordLimited( G4FieldTrack& yCurrent,
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| 177 | G4double stepMax,
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| 178 | G4double epsStep,
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| 179 | const G4ThreeVector latestSafetyOrigin,
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| 180 | G4double latestSafetyRadius
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| 181 | )
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| 182 | {
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| 183 | G4double stepPossible;
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| 184 | G4double dyErr;
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| 185 | G4FieldTrack yEnd( yCurrent);
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| 186 | G4double startCurveLen= yCurrent.GetCurveLength();
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| 187 | G4double nextStep;
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| 188 | // *************
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| 189 | stepPossible= FindNextChord(yCurrent, stepMax, yEnd, dyErr, epsStep, &nextStep
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| 190 | , latestSafetyOrigin, latestSafetyRadius
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| 191 | );
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| 192 | // *************
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| [850] | 193 | // G4cout<<"Exit Find Next Chord Err= "<<dyErr<<" eps= "<<epsStep<<"stepPos= "<<stepPossible<<G4endl;
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| [831] | 194 | G4bool good_advance;
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| [850] | 195 |
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| [831] | 196 | if ( dyErr < epsStep * stepPossible )
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| [850] | 197 |
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| 198 | { //G4cout<<"err comparison = "<<dyErr<<" eps= "<<epsStep<<G4endl;
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| [831] | 199 | // Accept this accuracy.
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| 200 | yCurrent = yEnd;
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| 201 | good_advance = true;
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| 202 | }
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| 203 | else
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| [850] | 204 | {
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| 205 | // G4cout<<"Entering Accurate Advance"<<G4endl;
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| [831] | 206 | // Advance more accurately to "end of chord"
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| 207 | // ***************
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| 208 | good_advance = fIntgrDriver->AccurateAdvance(yCurrent, stepPossible, epsStep, nextStep);
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| 209 | // ***************
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| 210 | if ( ! good_advance ){
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| 211 | // In this case the driver could not do the full distance
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| 212 | stepPossible= yCurrent.GetCurveLength()-startCurveLen;
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| 213 | }
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| 214 | }
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| 215 |
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| 216 | #ifdef G4DEBUG_FIELD
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| [850] | 217 | //G4cout << "Exiting FindNextChord Limited with:" << G4endl
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| 218 | // << " yCurrent: " << yCurrent<< G4endl;
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| [831] | 219 | #endif
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| 220 |
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| 221 | return stepPossible;
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| 222 | }
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| 223 |
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| 224 | // #define TEST_CHORD_PRINT 1
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| 225 |
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| 226 | // ............................................................................
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| 227 |
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| 228 | G4double
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| [850] | 229 | G4ChordFinder::FindNextChord( const G4FieldTrack& yStart,
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| [831] | 230 | G4double stepMax,
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| 231 | G4FieldTrack& yEnd, // Endpoint
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| 232 | G4double& dyErrPos, // Error of endpoint
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| 233 | G4double epsStep,
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| 234 | G4double* pStepForAccuracy,
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| 235 | const G4ThreeVector, // latestSafetyOrigin,
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| 236 | G4double // latestSafetyRadius
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| 237 | )
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| 238 | // Returns Length of Step taken
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| 239 | {
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| [850] | 240 | //G4cout<<"Inter Find Next Chord with step="<<stepMax<<G4endl;
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| [831] | 241 | // G4int stepRKnumber=0;
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| 242 | G4FieldTrack yCurrent= yStart;
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| 243 | G4double stepTrial, stepForAccuracy;
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| 244 | G4double dydx[G4FieldTrack::ncompSVEC];
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| 245 |
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| 246 | // 1.) Try to "leap" to end of interval
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| 247 | // 2.) Evaluate if resulting chord gives d_chord that is good enough.
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| 248 | // 2a.) If d_chord is not good enough, find one that is.
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| 249 |
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| 250 | G4bool validEndPoint= false;
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| 251 | G4double dChordStep, lastStepLength; // stepOfLastGoodChord;
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| 252 |
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| 253 | fIntgrDriver-> GetDerivatives( yCurrent, dydx ) ;
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| [850] | 254 | //for (G4int i=0;i<G4FieldTrack::ncompSVEC;i++){
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| 255 | // dydx[i]=0.;
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| 256 | //}
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| [831] | 257 | G4int noTrials=0;
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| 258 | const G4double safetyFactor= fFirstFraction; // 0.975 or 0.99 ? was 0.999
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| 259 |
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| 260 | stepTrial = std::min( stepMax,
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| 261 | safetyFactor * fLastStepEstimate_Unconstrained );
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| 262 |
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| 263 | G4double newStepEst_Uncons= 0.0;
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| 264 | do
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| 265 | {
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| 266 | G4double stepForChord;
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| 267 | yCurrent = yStart; // Always start from initial point
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| [850] | 268 |
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| [831] | 269 | // ************
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| 270 | fIntgrDriver->QuickAdvance( yCurrent, dydx, stepTrial,
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| 271 | dChordStep, dyErrPos);
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| 272 | // ************
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| 273 |
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| [850] | 274 | // G4cout<<"AfterQuickAdv step="<<stepTrial<<" dC="<<dChordStep<<" yErr="<<dyErrPos<<G4endl;
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| 275 |
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| 276 | // We check whether the criterion is met here.
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| 277 | validEndPoint = AcceptableMissDist(dChordStep);
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| 278 | // if(validEndPoint){G4cout<<"validEndPoint"<<fDeltaChord<<G4endl;}
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| 279 | // else{G4cout<<"No__validEndPoint"<<G4endl;}
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| [831] | 280 |
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| [850] | 281 |
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| 282 | //&& (dyErrPos < eps) ;
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| 283 | // validEndPoint = AcceptableMissDist(dChordStep) && (dyErrPos < epsStep) ;
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| 284 |
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| [831] | 285 | lastStepLength = stepTrial;
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| 286 |
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| 287 | // This method estimates to step size for a good chord.
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| 288 | stepForChord = NewStep(stepTrial, dChordStep, newStepEst_Uncons );
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| 289 |
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| 290 | if( ! validEndPoint ) {
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| 291 | if( stepTrial<=0.0 )
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| 292 | stepTrial = stepForChord;
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| 293 | else if (stepForChord <= stepTrial)
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| 294 | // Reduce by a fraction, possibly up to 20%
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| 295 | stepTrial = std::min( stepForChord,
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| 296 | fFractionLast * stepTrial);
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| 297 | else
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| 298 | stepTrial *= 0.1;
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| 299 |
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| 300 | // if(dbg) G4cerr<<"Dchord too big. Try new hstep="<<stepTrial<<G4endl;
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| 301 | }
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| 302 | // #ifdef TEST_CHORD_PRINT
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| 303 | // TestChordPrint( noTrials, lastStepLength, dChordStep, stepTrial );
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| 304 | // #endif
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| 305 |
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| 306 | noTrials++;
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| 307 | }
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| 308 | while( ! validEndPoint ); // End of do-while RKD
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| 309 |
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| 310 | if( newStepEst_Uncons > 0.0 ){
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| 311 | fLastStepEstimate_Unconstrained= newStepEst_Uncons;
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| 312 | }
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| 313 |
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| 314 | AccumulateStatistics( noTrials );
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| 315 |
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| 316 | // stepOfLastGoodChord = stepTrial;
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| 317 |
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| 318 | if( pStepForAccuracy ){
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| 319 | // Calculate the step size required for accuracy, if it is needed
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| 320 | G4double dyErr_relative = dyErrPos/(epsStep*lastStepLength);
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| 321 | if( dyErr_relative > 1.0 ) {
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| 322 | stepForAccuracy =
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| 323 | fIntgrDriver->ComputeNewStepSize( dyErr_relative,
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| 324 | lastStepLength );
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| 325 | }else{
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| 326 | stepForAccuracy = 0.0; // Convention to show step was ok
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| 327 | }
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| 328 | *pStepForAccuracy = stepForAccuracy;
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| 329 | }
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| 330 |
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| 331 | #ifdef TEST_CHORD_PRINT
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| 332 | static int dbg=0;
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| 333 | if( dbg )
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| 334 | G4cout << "ChordF/FindNextChord: NoTrials= " << noTrials
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| 335 | << " StepForGoodChord=" << std::setw(10) << stepTrial << G4endl;
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| 336 | #endif
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| [850] | 337 | //G4cout << "ChordF/FindNextChord: NoTrials= " << noTrials
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| 338 | // << " StepForGoodChord=" << std::setw(10) << stepTrial << G4endl;
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| [831] | 339 | yEnd= yCurrent;
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| 340 | return stepTrial;
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| 341 | }
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| 342 |
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| 343 | // ----------------------------------------------------------------------------
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| 344 | #if 0
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| 345 | // #ifdef G4VERBOSE
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| 346 | if( dbg ) {
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| 347 | G4cerr << "Returned from QuickAdvance with: yCur=" << yCurrent <<G4endl;
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| 348 | G4cerr << " dChordStep= "<< dChordStep <<" dyErr=" << dyErr << G4endl;
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| 349 | }
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| 350 | #endif
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| 351 | // ----------------------------------------------------------------------------
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| 352 |
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| 353 | // ...........................................................................
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| 354 |
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| 355 | G4double G4ChordFinder::NewStep(G4double stepTrialOld,
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| 356 | G4double dChordStep, // Curr. dchord achieved
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| 357 | G4double& stepEstimate_Unconstrained )
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| 358 | //
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| 359 | // Is called to estimate the next step size, even for successful steps,
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| 360 | // in order to predict an accurate 'chord-sensitive' first step
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| 361 | // which is likely to assist in more performant 'stepping'.
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| 362 | //
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| 363 |
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| 364 | {
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| 365 | G4double stepTrial;
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| 366 | static G4double lastStepTrial = 1., lastDchordStep= 1.;
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| 367 |
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| 368 | #if 1
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| 369 | // const G4double threshold = 1.21, multiplier = 0.9;
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| 370 | // 0.9 < 1 / std::sqrt(1.21)
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| 371 |
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| 372 | if (dChordStep > 0.0)
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| 373 | {
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| 374 | stepEstimate_Unconstrained = stepTrialOld*std::sqrt( fDeltaChord / dChordStep );
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| 375 | // stepTrial = 0.98 * stepEstimate_Unconstrained;
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| 376 | stepTrial = fFractionNextEstimate * stepEstimate_Unconstrained;
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| 377 | }
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| 378 | else
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| 379 | {
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| 380 | // Should not update the Unconstrained Step estimate: incorrect!
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| 381 | stepTrial = stepTrialOld * 2.;
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| 382 | }
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| 383 |
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|---|
| 384 | // if ( dChordStep < threshold * fDeltaChord ){
|
|---|
| 385 | // stepTrial= stepTrialOld * multiplier;
|
|---|
| 386 | // }
|
|---|
| 387 | if( stepTrial <= 0.001 * stepTrialOld)
|
|---|
| 388 | {
|
|---|
| 389 | if ( dChordStep > 1000.0 * fDeltaChord ){
|
|---|
| 390 | stepTrial= stepTrialOld * 0.03;
|
|---|
| 391 | }else{
|
|---|
| 392 | if ( dChordStep > 100. * fDeltaChord ){
|
|---|
| 393 | stepTrial= stepTrialOld * 0.1;
|
|---|
| 394 | }else{
|
|---|
| 395 | // Try halving the length until dChordStep OK
|
|---|
| 396 | stepTrial= stepTrialOld * 0.5;
|
|---|
| 397 | }
|
|---|
| 398 | }
|
|---|
| 399 | }else if (stepTrial > 1000.0 * stepTrialOld)
|
|---|
| 400 | {
|
|---|
| 401 | stepTrial= 1000.0 * stepTrialOld;
|
|---|
| 402 | }
|
|---|
| 403 |
|
|---|
| 404 | if( stepTrial == 0.0 ){
|
|---|
| 405 | stepTrial= 0.000001;
|
|---|
| 406 | }
|
|---|
| 407 |
|
|---|
| 408 | lastStepTrial = stepTrialOld;
|
|---|
| 409 | lastDchordStep= dChordStep;
|
|---|
| 410 | #else
|
|---|
| 411 | if ( dChordStep > 1000. * fDeltaChord ){
|
|---|
| 412 | stepTrial= stepTrialOld * 0.03;
|
|---|
| 413 | }else{
|
|---|
| 414 | if ( dChordStep > 100. * fDeltaChord ){
|
|---|
| 415 | stepTrial= stepTrialOld * 0.1;
|
|---|
| 416 | }else{
|
|---|
| 417 | // Keep halving the length until dChordStep OK
|
|---|
| 418 | stepTrial= stepTrialOld * 0.5;
|
|---|
| 419 | }
|
|---|
| 420 | }
|
|---|
| 421 | #endif
|
|---|
| 422 |
|
|---|
| 423 | // A more sophisticated chord-finder could figure out a better
|
|---|
| 424 | // stepTrial, from dChordStep and the required d_geometry
|
|---|
| 425 | // eg
|
|---|
| 426 | // Calculate R, r_helix (eg at orig point)
|
|---|
| 427 | // if( stepTrial < 2 pi R )
|
|---|
| 428 | // stepTrial = R arc_cos( 1 - fDeltaChord / r_helix )
|
|---|
| 429 | // else
|
|---|
| 430 | // ??
|
|---|
| 431 |
|
|---|
| 432 | return stepTrial;
|
|---|
| 433 | }
|
|---|
| 434 |
|
|---|
| [850] | 435 | // ApproxCurvePointS is 2nd implementation of ApproxCurvePoint.
|
|---|
| 436 | // Use Brent Algorithm(or InvParabolic) when it possible.
|
|---|
| 437 | // Given a starting curve point A (CurveA_PointVelocity),
|
|---|
| 438 | // curve point B (CurveB_PointVelocity), a point E which is (generally)
|
|---|
| 439 | // not on the curve and a point F which is on the curve(first approximation)
|
|---|
| 440 | // From this information find new point S on the curve closer to point E.
|
|---|
| 441 | // While advancing towards S utilise eps_step
|
|---|
| [831] | 442 | // as a measure of the relative accuracy of each Step.
|
|---|
| 443 | G4FieldTrack
|
|---|
| [850] | 444 | G4ChordFinder::ApproxCurvePointS( const G4FieldTrack& CurveA_PointVelocity,
|
|---|
| 445 | const G4FieldTrack& CurveB_PointVelocity,
|
|---|
| 446 | const G4ThreeVector& CurrentE_Point,
|
|---|
| 447 | const G4ThreeVector& CurrentF_Point,
|
|---|
| 448 | const G4ThreeVector& PointG,
|
|---|
| 449 | G4bool first, G4double eps_step)
|
|---|
| 450 | {
|
|---|
| 451 |
|
|---|
| 452 |
|
|---|
| 453 | G4FieldTrack EndPoint( CurveA_PointVelocity);
|
|---|
| 454 | G4ThreeVector Point_A=CurveA_PointVelocity.GetPosition();
|
|---|
| 455 | G4ThreeVector Point_B=CurveB_PointVelocity.GetPosition();
|
|---|
| 456 | G4double xa,xb,xc,ya,yb,yc;
|
|---|
| 457 |
|
|---|
| 458 | //InverseParabolic
|
|---|
| 459 | //AF Intersects (First Part of Curve)
|
|---|
| 460 | if(first){
|
|---|
| 461 | xa=0.;
|
|---|
| 462 | ya=(PointG-Point_A).mag();
|
|---|
| 463 | xb=(Point_A-CurrentF_Point).mag();
|
|---|
| 464 | yb=-(PointG-CurrentF_Point).mag();
|
|---|
| 465 | xc=(Point_A-Point_B).mag();
|
|---|
| 466 | yc=-(CurrentE_Point-Point_B).mag();
|
|---|
| 467 | }
|
|---|
| 468 | else{
|
|---|
| 469 | xa=0.;
|
|---|
| 470 | ya=(Point_A-PointG).mag();
|
|---|
| 471 | xb=(Point_B-Point_A).mag();
|
|---|
| 472 | yb=-(PointG-Point_B).mag();
|
|---|
| 473 | xc=-(Point_A-CurrentF_Point).mag();
|
|---|
| 474 | yc=-(Point_A-CurrentE_Point).mag();
|
|---|
| 475 |
|
|---|
| 476 | }
|
|---|
| 477 | const G4double tolerance= 1.e-12;
|
|---|
| 478 | if(ya<=tolerance||std::abs(yc)<=tolerance){
|
|---|
| 479 | ; //What to do for the moment return the same point as in begin
|
|---|
| 480 | //Then PropagatorInField will take care
|
|---|
| 481 | }
|
|---|
| 482 | else{
|
|---|
| 483 |
|
|---|
| 484 | G4double test_step =InvParabolic(xa,ya,xb,yb,xc,yc);
|
|---|
| 485 | G4double curve=std::abs(EndPoint.GetCurveLength()-CurveB_PointVelocity.GetCurveLength());
|
|---|
| 486 | G4double dist= (EndPoint.GetPosition()-Point_B).mag();
|
|---|
| 487 | if(test_step<=0) { test_step=0.1*xb;}
|
|---|
| 488 | if(test_step>=xb){ test_step=0.5*xb;}
|
|---|
| 489 |
|
|---|
| 490 |
|
|---|
| 491 | if(curve*(1.+eps_step)<dist){
|
|---|
| 492 | test_step=0.5*dist;
|
|---|
| 493 | }
|
|---|
| 494 |
|
|---|
| 495 | G4bool goodAdvance;
|
|---|
| 496 | goodAdvance=
|
|---|
| 497 | fIntgrDriver->AccurateAdvance(EndPoint,test_step, eps_step);
|
|---|
| 498 | // ***************
|
|---|
| 499 |
|
|---|
| 500 | #ifdef G4DEBUG_FIELD
|
|---|
| 501 | G4cout<<"G4ChordFinder:: test-step ShF="<<test_step<<" EndPoint="<<EndPoint<<G4endl;
|
|---|
| 502 | // Test Track
|
|---|
| 503 | G4FieldTrack TestTrack( CurveA_PointVelocity);
|
|---|
| 504 | TestTrack = ApproxCurvePointV( CurveA_PointVelocity,
|
|---|
| 505 | CurveB_PointVelocity,
|
|---|
| 506 | CurrentE_Point,
|
|---|
| 507 | eps_step );
|
|---|
| 508 | G4cout.precision(14);
|
|---|
| 509 | G4cout<<"G4ChordFinder:: BrentApprox="<<EndPoint<<G4endl;
|
|---|
| 510 | G4cout<<"G4ChordFinder::LinearApprox="<<TestTrack<<G4endl;
|
|---|
| 511 | #endif
|
|---|
| 512 | }
|
|---|
| 513 | return EndPoint;
|
|---|
| 514 | }
|
|---|
| 515 |
|
|---|
| 516 | G4FieldTrack
|
|---|
| [831] | 517 | G4ChordFinder::ApproxCurvePointV( const G4FieldTrack& CurveA_PointVelocity,
|
|---|
| 518 | const G4FieldTrack& CurveB_PointVelocity,
|
|---|
| 519 | const G4ThreeVector& CurrentE_Point,
|
|---|
| 520 | G4double eps_step)
|
|---|
| 521 | {
|
|---|
| 522 | // 1st implementation:
|
|---|
| 523 | // if r=|AE|/|AB|, and s=true path lenght (AB)
|
|---|
| 524 | // return the point that is r*s along the curve!
|
|---|
| [850] | 525 | /////////////////////////////
|
|---|
| 526 | //
|
|---|
| 527 | //2st implementation : Inverse Parabolic Extrapolation by D.C.Williams
|
|---|
| 528 | //
|
|---|
| 529 | // Uses InvParabolic (xa,ya,xb,yb,xc,yc)
|
|---|
| [831] | 530 |
|
|---|
| [850] | 531 | G4FieldTrack Current_PointVelocity = CurveA_PointVelocity;
|
|---|
| [831] | 532 |
|
|---|
| 533 | G4ThreeVector CurveA_Point= CurveA_PointVelocity.GetPosition();
|
|---|
| 534 | G4ThreeVector CurveB_Point= CurveB_PointVelocity.GetPosition();
|
|---|
| 535 |
|
|---|
| 536 | G4ThreeVector ChordAB_Vector= CurveB_Point - CurveA_Point;
|
|---|
| 537 | G4ThreeVector ChordAE_Vector= CurrentE_Point - CurveA_Point;
|
|---|
| 538 |
|
|---|
| 539 | G4double ABdist= ChordAB_Vector.mag();
|
|---|
| 540 | G4double curve_length; // A curve length of AB
|
|---|
| 541 | G4double AE_fraction;
|
|---|
| 542 |
|
|---|
| 543 | curve_length= CurveB_PointVelocity.GetCurveLength()
|
|---|
| 544 | - CurveA_PointVelocity.GetCurveLength();
|
|---|
| 545 |
|
|---|
| 546 | // const
|
|---|
| 547 | G4double integrationInaccuracyLimit= std::max( perMillion, 0.5*eps_step );
|
|---|
| 548 | if( curve_length < ABdist * (1. - integrationInaccuracyLimit) ){
|
|---|
| 549 | #ifdef G4DEBUG_FIELD
|
|---|
| 550 | G4cerr << " Warning in G4ChordFinder::ApproxCurvePoint: "
|
|---|
| 551 | << G4endl
|
|---|
| 552 | << " The two points are further apart than the curve length "
|
|---|
| 553 | << G4endl
|
|---|
| 554 | << " Dist = " << ABdist
|
|---|
| 555 | << " curve length = " << curve_length
|
|---|
| 556 | << " relativeDiff = " << (curve_length-ABdist)/ABdist
|
|---|
| 557 | << G4endl;
|
|---|
| 558 | if( curve_length < ABdist * (1. - 10*eps_step) ) {
|
|---|
| 559 | G4cerr << " ERROR: the size of the above difference"
|
|---|
| 560 | << " exceeds allowed limits. Aborting." << G4endl;
|
|---|
| 561 | G4Exception("G4ChordFinder::ApproxCurvePointV()", "PrecisionError",
|
|---|
| 562 | FatalException, "Unphysical curve length.");
|
|---|
| 563 | }
|
|---|
| 564 | #endif
|
|---|
| 565 | // Take default corrective action:
|
|---|
| 566 | // --> adjust the maximum curve length.
|
|---|
| 567 | // NOTE: this case only happens for relatively straight paths.
|
|---|
| 568 | curve_length = ABdist;
|
|---|
| 569 | }
|
|---|
| 570 |
|
|---|
| 571 | G4double new_st_length;
|
|---|
| 572 |
|
|---|
| 573 | if ( ABdist > 0.0 ){
|
|---|
| 574 | AE_fraction = ChordAE_Vector.mag() / ABdist;
|
|---|
| 575 | }else{
|
|---|
| 576 | AE_fraction = 0.5; // Guess .. ?;
|
|---|
| 577 | #ifdef G4DEBUG_FIELD
|
|---|
| 578 | G4cout << "Warning in G4ChordFinder::ApproxCurvePoint:"
|
|---|
| 579 | << " A and B are the same point!" << G4endl
|
|---|
| 580 | << " Chord AB length = " << ChordAE_Vector.mag() << G4endl
|
|---|
| 581 | << G4endl;
|
|---|
| 582 | #endif
|
|---|
| 583 | }
|
|---|
| 584 |
|
|---|
| 585 | if( (AE_fraction> 1.0 + perMillion) || (AE_fraction< 0.) ){
|
|---|
| 586 | #ifdef G4DEBUG_FIELD
|
|---|
| 587 | G4cerr << " G4ChordFinder::ApproxCurvePointV - Warning:"
|
|---|
| 588 | << " Anomalous condition:AE > AB or AE/AB <= 0 " << G4endl
|
|---|
| 589 | << " AE_fraction = " << AE_fraction << G4endl
|
|---|
| 590 | << " Chord AE length = " << ChordAE_Vector.mag() << G4endl
|
|---|
| 591 | << " Chord AB length = " << ABdist << G4endl << G4endl;
|
|---|
| 592 | G4cerr << " OK if this condition occurs after a recalculation of 'B'"
|
|---|
| 593 | << G4endl << " Otherwise it is an error. " << G4endl ;
|
|---|
| 594 | #endif
|
|---|
| 595 | // This course can now result if B has been re-evaluated,
|
|---|
| 596 | // without E being recomputed (1 July 99)
|
|---|
| 597 | // In this case this is not a "real error" - but it undesired
|
|---|
| 598 | // and we cope with it by a default corrective action ...
|
|---|
| 599 | AE_fraction = 0.5; // Default value
|
|---|
| 600 | }
|
|---|
| 601 |
|
|---|
| 602 | new_st_length= AE_fraction * curve_length;
|
|---|
| 603 |
|
|---|
| 604 | G4bool good_advance;
|
|---|
| 605 | if ( AE_fraction > 0.0 ) {
|
|---|
| 606 | good_advance =
|
|---|
| 607 | fIntgrDriver->AccurateAdvance(Current_PointVelocity,
|
|---|
| 608 | new_st_length,
|
|---|
| 609 | eps_step ); // Relative accuracy
|
|---|
| 610 | // In this case it does not matter if it cannot advance the full distance
|
|---|
| 611 | }
|
|---|
| 612 |
|
|---|
| 613 | // If there was a memory of the step_length actually require at the start
|
|---|
| 614 | // of the integration Step, this could be re-used ...
|
|---|
| [850] | 615 | G4cout.precision(14);
|
|---|
| 616 |
|
|---|
| 617 | // G4cout<<"G4ChordFinder::LinearApprox="<<Current_PointVelocity<<G4endl;
|
|---|
| [831] | 618 | return Current_PointVelocity;
|
|---|
| 619 | }
|
|---|
| 620 |
|
|---|
| 621 | void
|
|---|
| 622 | G4ChordFinder::TestChordPrint( G4int noTrials,
|
|---|
| 623 | G4int lastStepTrial,
|
|---|
| 624 | G4double dChordStep,
|
|---|
| 625 | G4double nextStepTrial )
|
|---|
| 626 | {
|
|---|
| 627 | G4int oldprec= G4cout.precision(5);
|
|---|
| 628 | G4cout << " ChF/fnc: notrial " << std::setw( 3) << noTrials
|
|---|
| 629 | << " this_step= " << std::setw(10) << lastStepTrial;
|
|---|
| 630 | if( std::fabs( (dChordStep / fDeltaChord) - 1.0 ) < 0.001 ){
|
|---|
| 631 | G4cout.precision(8);
|
|---|
| 632 | }else{ G4cout.precision(6); }
|
|---|
| 633 | G4cout << " dChordStep= " << std::setw(12) << dChordStep;
|
|---|
| 634 | if( dChordStep > fDeltaChord ) { G4cout << " d+"; }
|
|---|
| 635 | else { G4cout << " d-"; }
|
|---|
| 636 | G4cout.precision(5);
|
|---|
| 637 | G4cout << " new_step= " << std::setw(10)
|
|---|
| 638 | << fLastStepEstimate_Unconstrained
|
|---|
| 639 | << " new_step_constr= " << std::setw(10)
|
|---|
| 640 | << lastStepTrial << G4endl;
|
|---|
| 641 | G4cout << " nextStepTrial = " << std::setw(10) << nextStepTrial << G4endl;
|
|---|
| 642 | G4cout.precision(oldprec);
|
|---|
| 643 | }
|
|---|