Geant4 Cross Reference |
1 // 1 2 // ******************************************* 3 // * License and Disclaimer 4 // * 5 // * The Geant4 software is copyright of th 6 // * the Geant4 Collaboration. It is provided 7 // * conditions of the Geant4 Software License 8 // * LICENSE and available at http://cern.ch/ 9 // * include a list of copyright holders. 10 // * 11 // * Neither the authors of this software syst 12 // * institutes,nor the agencies providing fin 13 // * work make any representation or warran 14 // * regarding this software system or assum 15 // * use. Please see the license in the file 16 // * for the full disclaimer and the limitatio 17 // * 18 // * This code implementation is the result 19 // * technical work of the GEANT4 collaboratio 20 // * By using, copying, modifying or distri 21 // * any work based on the software) you ag 22 // * use in resulting scientific publicati 23 // * acceptance of all terms of the Geant4 Sof 24 // ******************************************* 25 // 26 // G4MagErrorStepper implementation 27 // 28 // Author: W.Wander <wwc@mit.edu>, 09.12.1997 29 // ------------------------------------------- 30 31 #include "G4MagErrorStepper.hh" 32 #include "G4LineSection.hh" 33 34 G4MagErrorStepper::~G4MagErrorStepper() 35 { 36 delete [] yMiddle; 37 delete [] dydxMid; 38 delete [] yInitial; 39 delete [] yOneStep; 40 } 41 42 void G4MagErrorStepper::Stepper( const G4doubl 43 const G4doubl 44 G4doubl 45 G4doubl 46 G4doubl 47 { 48 const G4int nvar = GetNumberOfVariables(); 49 const G4int maxvar = GetNumberOfStateVariab 50 51 // correction for Richardson Extrapolation. 52 // 53 G4double correction = 1. / ( (1 << Integra 54 55 // Saving yInput because yInput and yOutpu 56 // 57 for(G4int i=0; i<nvar; ++i) 58 { 59 yInitial[i]=yInput[i]; 60 } 61 yInitial[7] = yInput[7]; // Copy the time i 62 yMiddle[7] = yInput[7]; // Copy the time f 63 yOneStep[7] = yInput[7]; // As it contribut 64 // yOutput[7] = yInput[7]; // -> dumb step 65 66 for(G4int i=nvar; i<maxvar; ++i) 67 { 68 yOutput[i]=yInput[i]; 69 } 70 // yError[7] = 0.0; 71 72 G4double halfStep = hstep * 0.5; 73 74 // Do two half steps 75 // 76 DumbStepper (yInitial, dydx, halfStep, 77 RightHandSide(yMiddle, dydxMid); 78 DumbStepper (yMiddle, dydxMid, halfStep, y 79 80 // Store midpoint, chord calculation 81 // 82 fMidPoint = G4ThreeVector( yMiddle[0], yMi 83 84 // Do a full Step 85 // 86 DumbStepper(yInitial, dydx, hstep, yOneStep 87 for(G4int i=0; i<nvar; ++i) 88 { 89 yError [i] = yOutput[i] - yOneStep[i] ; 90 yOutput[i] += yError[i]*correction ; 91 // Provides accuracy increased by 1 or 92 } 93 94 fInitialPoint = G4ThreeVector( yInitial[0], 95 fFinalPoint = G4ThreeVector( yOutput[0], 96 97 return; 98 } 99 100 G4double G4MagErrorStepper::DistChord() const 101 { 102 // Estimate the maximum distance from the cu 103 // 104 // We estimate this using the distance of th 105 // chord (the line between 106 // 107 // Method below is good only for angle devia 108 // This restriction should not a problem for 109 // which generally cannot integrate accurate 110 111 G4double distLine, distChord; 112 113 if (fInitialPoint != fFinalPoint) 114 { 115 distLine = G4LineSection::Distline(fMidPo 116 // This is a class method that gives di 117 // from the Chord between the Initial a 118 119 distChord = distLine; 120 } 121 else 122 { 123 distChord = (fMidPoint-fInitialPoint).mag 124 } 125 126 return distChord; 127 } 128