| [990] | 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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| 27 | // $Id: G4RandomTools.hh,v 1.2 2008/11/07 17:54:21 gum Exp $
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| 28 | // GEANT4 tag $Name: geant4-09-02-ref-02 $
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| 29 | //
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| 30 | //
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| 31 | // ---------------------------------------------------------------------------
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| 32 | // GEANT 4 class header file
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| 33 | // ---------------------------------------------------------------------------
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| 34 | // Class description:
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| 35 | //
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| 36 | // Utility functions
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| 37 |
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| 38 | // History:
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| 39 | //
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| 40 | // 07.11.08 - P.Gumplinger, based on implementation in G4OpBoundaryProcess
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| 41 | //
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| 42 | // ---------------------------------------------------------------------------
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| 43 |
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| 44 | #ifndef G4RANDOMTOOLS_HH
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| 45 | #define G4RANDOMTOOLS_HH
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| 46 |
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| 47 | #include "globals.hh"
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| 48 | #include "Randomize.hh"
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| 49 | #include "G4RandomDirection.hh"
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| 50 |
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| 51 | // ---------------------------------------------------------------------------
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| 52 | // Returns a random lambertian unit vector
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| 53 | //
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| 54 | inline G4ThreeVector G4LambertianRand(const G4ThreeVector& normal)
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| 55 | {
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| 56 | G4ThreeVector vect;
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| 57 | G4double ndotv;
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| 58 |
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| 59 | do
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| 60 | {
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| 61 | vect = G4RandomDirection();
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| 62 | ndotv = normal * vect;
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| 63 |
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| 64 | if (ndotv < 0.0)
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| 65 | {
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| 66 | vect = -vect;
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| 67 | ndotv = -ndotv;
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| 68 | }
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| 69 |
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| 70 | } while (!(G4UniformRand() < ndotv));
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| 71 |
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| 72 | return vect;
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| 73 | }
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| 74 |
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| 75 | // ---------------------------------------------------------------------------
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| 76 | // Chooses a random vector within a plane given by the unit normal
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| 77 | //
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| 78 | inline G4ThreeVector G4PlaneVectorRand(const G4ThreeVector& normal)
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| 79 | {
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| 80 | G4ThreeVector vec1 = normal.orthogonal();
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| 81 | G4ThreeVector vec2 = vec1.cross(normal);
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| 82 |
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| 83 | G4double phi = twopi*G4UniformRand();
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| 84 | G4double cosphi = std::cos(phi);
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| 85 | G4double sinphi = std::sin(phi);
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| 86 |
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| 87 | return cosphi * vec1 + sinphi * vec2;
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| 88 | }
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| 89 |
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| 90 | #endif /* G4RANDOMTOOLS_HH */
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