00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // 00027 // $Id$ 00028 // 00029 // 00030 // --------------------------------------------------------------------------- 00031 // GEANT 4 class header file 00032 // --------------------------------------------------------------------------- 00033 // Class description: 00034 // 00035 // Utility functions 00036 00037 // History: 00038 // 00039 // 07.11.08 - P.Gumplinger, based on implementation in G4OpBoundaryProcess 00040 // 00041 // --------------------------------------------------------------------------- 00042 00043 #ifndef G4RANDOMTOOLS_HH 00044 #define G4RANDOMTOOLS_HH 00045 00046 #include <CLHEP/Units/PhysicalConstants.h> 00047 00048 #include "globals.hh" 00049 #include "Randomize.hh" 00050 #include "G4RandomDirection.hh" 00051 00052 // --------------------------------------------------------------------------- 00053 // Returns a random lambertian unit vector 00054 // 00055 inline G4ThreeVector G4LambertianRand(const G4ThreeVector& normal) 00056 { 00057 G4ThreeVector vect; 00058 G4double ndotv; 00059 00060 do 00061 { 00062 vect = G4RandomDirection(); 00063 ndotv = normal * vect; 00064 00065 if (ndotv < 0.0) 00066 { 00067 vect = -vect; 00068 ndotv = -ndotv; 00069 } 00070 00071 } while (!(G4UniformRand() < ndotv)); 00072 00073 return vect; 00074 } 00075 00076 // --------------------------------------------------------------------------- 00077 // Chooses a random vector within a plane given by the unit normal 00078 // 00079 inline G4ThreeVector G4PlaneVectorRand(const G4ThreeVector& normal) 00080 { 00081 G4ThreeVector vec1 = normal.orthogonal(); 00082 G4ThreeVector vec2 = vec1.cross(normal); 00083 00084 G4double phi = CLHEP::twopi*G4UniformRand(); 00085 G4double cosphi = std::cos(phi); 00086 G4double sinphi = std::sin(phi); 00087 00088 return cosphi * vec1 + sinphi * vec2; 00089 } 00090 00091 #endif /* G4RANDOMTOOLS_HH */