[819] | 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 | // $Id: G4StokesVector.cc,v 1.3 2006/11/17 11:59:03 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: $ |
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| 28 | // |
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| 29 | // GEANT4 Class file |
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| 30 | // |
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| 31 | // |
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| 32 | // File name: G4StokesVector |
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| 33 | // |
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| 34 | // Author: Andreas Schaelicke |
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| 35 | // |
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| 36 | // Creation date: 01.05.2005 |
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| 37 | // |
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| 38 | // Modifications: |
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| 39 | // |
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| 40 | // Class Description: |
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| 41 | // |
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| 42 | // Provides Stokesvector representation employed in polarized |
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| 43 | // processes. |
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| 44 | // |
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| 45 | #include "G4StokesVector.hh" |
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| 46 | #include "G4PolarizationHelper.hh" |
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| 47 | #include "Randomize.hh" |
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| 48 | |
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| 49 | const G4StokesVector G4StokesVector::ZERO=G4ThreeVector(0.,0.,0.); |
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| 50 | const G4StokesVector G4StokesVector::P1=G4ThreeVector(1.,0.,0.); |
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| 51 | const G4StokesVector G4StokesVector::P2=G4ThreeVector(0.,1.,0.); |
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| 52 | const G4StokesVector G4StokesVector::P3=G4ThreeVector(0.,0.,1.); |
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| 53 | const G4StokesVector G4StokesVector::M1=G4ThreeVector(-1.,0.,0.); |
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| 54 | const G4StokesVector G4StokesVector::M2=G4ThreeVector(0.,-1.,0.); |
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| 55 | const G4StokesVector G4StokesVector::M3=G4ThreeVector(0.,0.,-1.); |
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| 56 | |
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| 57 | G4StokesVector::G4StokesVector() |
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| 58 | : G4ThreeVector(),isPhoton(false) |
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| 59 | { |
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| 60 | } |
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| 61 | |
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| 62 | G4StokesVector::G4StokesVector(const G4ThreeVector & v) |
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| 63 | : G4ThreeVector(v),isPhoton(false) |
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| 64 | { |
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| 65 | } |
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| 66 | |
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| 67 | G4StokesVector::~G4StokesVector() |
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| 68 | { |
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| 69 | } |
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| 70 | |
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| 71 | void G4StokesVector::RotateAz(G4ThreeVector nInteractionFrame, |
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| 72 | G4ThreeVector particleDirection) |
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| 73 | { |
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| 74 | G4ThreeVector yParticleFrame = |
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| 75 | G4PolarizationHelper::GetParticleFrameY(particleDirection); |
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| 76 | |
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| 77 | |
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| 78 | G4double cosphi=yParticleFrame*nInteractionFrame; |
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| 79 | if (cosphi>(1.+1.e-8) || cosphi<(-1.-1.e-8)) { |
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| 80 | G4cout<<" warning G4StokesVector::RotateAz cosphi>1 or cosphi<-1\n" |
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| 81 | <<" cosphi="<<cosphi<<"\n" |
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| 82 | <<" zAxis="<<particleDirection<<" ("<<particleDirection.mag()<<")\n" |
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| 83 | <<" yAxis="<<yParticleFrame<<" ("<<yParticleFrame.mag()<<")\n" |
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| 84 | <<" nAxis="<<nInteractionFrame<<" (" |
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| 85 | <<nInteractionFrame.mag()<<")"<<G4endl; |
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| 86 | } |
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| 87 | if (cosphi>1.) cosphi=1.; |
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| 88 | else if (cosphi<-1.) cosphi=-1.; |
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| 89 | |
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| 90 | // G4cout<<" cosphi="<<cosphi<<"\n" |
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| 91 | // <<" zAxis="<<particleDirection<<" ("<<particleDirection.mag()<<")\n" |
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| 92 | // <<" yAxis="<<yParticleFrame<<" ("<<yParticleFrame.mag()<<","<<(yParticleFrame*particleDirection)<<")\n" |
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| 93 | // <<" nAxis="<<nInteractionFrame<<" (" |
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| 94 | // <<nInteractionFrame.mag()<<")"<<G4endl; |
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| 95 | |
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| 96 | // G4double hel=sgn(cross(yParticleFrame*nInteractionFrame)*zInteractionFrame); |
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| 97 | // Why not particleDirection instead of zInteractionFrame ???!!! |
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| 98 | // -> is the same, since SYSIN is called with p1, and p2 as first parameter! |
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| 99 | G4double hel=(cross(yParticleFrame*nInteractionFrame)*particleDirection)>0?1.:-1.; |
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| 100 | |
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| 101 | G4double sinphi=hel*std::sqrt(1.-cosphi*cosphi); |
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| 102 | // G4cout<<" sin2 + cos2 -1 = "<<(sinphi*sinphi+cosphi*cosphi-1)<<"\n"; |
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| 103 | |
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| 104 | RotateAz(cosphi,sinphi); |
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| 105 | } |
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| 106 | |
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| 107 | |
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| 108 | void G4StokesVector::InvRotateAz(G4ThreeVector nInteractionFrame, |
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| 109 | G4ThreeVector particleDirection) |
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| 110 | { |
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| 111 | // note if incomming particle is on z-axis, |
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| 112 | // we might encounter some nummerical problems, since |
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| 113 | // nInteratonFrame and yParticleFrame are actually (almost) the same momentum |
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| 114 | // and the normalization is only good to 10^-12 ! |
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| 115 | |
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| 116 | G4ThreeVector yParticleFrame = |
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| 117 | G4PolarizationHelper::GetParticleFrameY(particleDirection); |
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| 118 | G4double cosphi=yParticleFrame*nInteractionFrame; |
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| 119 | |
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| 120 | if (cosphi>1.+1.e-8 || cosphi<-1.-1.e-8) { |
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| 121 | G4cout<<" warning G4StokesVector::RotateAz cosphi>1 or cosphi<-1\n"; |
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| 122 | } |
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| 123 | if (cosphi>1) cosphi=1.; |
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| 124 | else if (cosphi<-1)cosphi=-1.; |
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| 125 | |
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| 126 | // check sign once more! |
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| 127 | G4double hel=(cross(yParticleFrame*nInteractionFrame)*particleDirection)>0?1.:-1.; |
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| 128 | G4double sinphi=hel*std::sqrt(std::fabs(1.-cosphi*cosphi)); |
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| 129 | RotateAz(cosphi,-sinphi); |
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| 130 | } |
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| 131 | |
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| 132 | void G4StokesVector::RotateAz(G4double cosphi, G4double sinphi) |
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| 133 | { |
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| 134 | if (!isPhoton) { |
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| 135 | G4double xsi1= cosphi*p1() + sinphi*p2(); |
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| 136 | G4double xsi2= -sinphi*p1() + cosphi*p2(); |
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| 137 | setX(xsi1); |
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| 138 | setY(xsi2); |
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| 139 | return; |
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| 140 | } |
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| 141 | |
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| 142 | G4double sin2phi=2.*cosphi*sinphi; |
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| 143 | G4double cos2phi=cosphi*cosphi-sinphi*sinphi; |
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| 144 | |
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| 145 | G4double xsi1= cos2phi*p1() + sin2phi*p2(); |
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| 146 | G4double xsi2= -sin2phi*p1() + cos2phi*p2(); |
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| 147 | setX(xsi1); |
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| 148 | setY(xsi2); |
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| 149 | } |
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| 150 | |
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| 151 | G4double G4StokesVector::GetBeta() |
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| 152 | { |
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| 153 | G4double beta=getPhi(); |
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| 154 | if (isPhoton) |
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| 155 | return 0.5*beta; |
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| 156 | return beta; |
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| 157 | } |
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| 158 | |
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| 159 | void G4StokesVector::DiceUniform() |
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| 160 | { |
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| 161 | G4double costheta=2.*G4UniformRand()-1.; |
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| 162 | G4double sintheta=std::sqrt(1.-costheta*costheta); |
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| 163 | G4double phi =2.*pi*G4UniformRand(); |
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| 164 | setX(std::sin(phi)*sintheta); |
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| 165 | setY(std::cos(phi)*sintheta); |
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| 166 | setZ(costheta); |
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| 167 | } |
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| 168 | |
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| 169 | void G4StokesVector::DiceP1() |
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| 170 | { |
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| 171 | if (G4UniformRand()>0.5) setX(1.); |
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| 172 | else setX(-1.); |
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| 173 | setY(0.); |
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| 174 | setZ(0.); |
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| 175 | } |
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| 176 | |
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| 177 | void G4StokesVector::DiceP2() |
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| 178 | { |
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| 179 | setX(0.); |
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| 180 | if (G4UniformRand()>0.5) setY(1.); |
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| 181 | else setY(-1.); |
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| 182 | setZ(0.); |
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| 183 | } |
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| 184 | |
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| 185 | void G4StokesVector::DiceP3() |
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| 186 | { |
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| 187 | setX(0.); |
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| 188 | setY(0.); |
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| 189 | if (G4UniformRand()>0.5) setZ(1.); |
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| 190 | else setZ(-1.); |
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| 191 | } |
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| 192 | |
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| 193 | void G4StokesVector::FlipP3() |
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| 194 | { |
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| 195 | setZ(-z()); |
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| 196 | } |
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| 197 | |
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| 198 | G4ThreeVector G4StokesVector::PolError(const G4StokesVector & sum2, long n) |
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| 199 | { |
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| 200 | // delta x = sqrt[ ( <x^2> - <x>^2 )/(n-1) ] |
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| 201 | G4StokesVector mean=(1./n)*(*this); |
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| 202 | return G4StokesVector((1./(n-1.)*((1./n)*sum2 - mean.PolSqr()))).PolSqrt(); |
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| 203 | } |
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| 204 | |
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| 205 | G4ThreeVector G4StokesVector::PolDiv(const G4StokesVector & b) |
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| 206 | {return G4ThreeVector(b.x()!=0. ? x()/b.x() : 11111., |
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| 207 | b.y()!=0. ? y()/b.y() : 11111., |
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| 208 | b.z()!=0. ? z()/b.z() : 11111.);} |
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