include/Geant4/G4Clebsch.hh

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0025 //
0026 //
0027 // -------------------------------------------------------------------
0028 //      GEANT4 Class file
0029 //
0030 //
0031 //      File name:     G4Clebsch
0032 //
0033 //      Author:        Maria Grazia Pia (MariaGrazia.Pia@genova.infn.it)
0034 //
0035 //      Creation date: 15 April 1999
0036 //
0037 //      Modifications: February 2015, Jason Detwiler (jasondet@gmail.com)
0038 //                     - Update variable names to clarify that twice
0039 //                       the spin value is being used.
0040 //                     - Add function to obtain raw CG coeffients
0041 //                     - Speed up Wigner 3j evaluation by removing
0042 //                       reallocation of vector<double>'s on every call
0043 //                     - Use G4Pow instead of internal logs variable
0044 //                     - Add functions for Wigner 6j and 9j symbols,
0045 //                       Racah coefficients, and d-Matrices
0046 //                     - Make functions statically available
0047 //                     - Eliminate unnecessary constructors, destructors,
0048 //                       operators (class has no members, so default versions
0049 //                       are adequate)
0050 //                     11.06.2015 V.Ivanchenko adopted for Geant4 source
0051 //
0052 //      Clebsch-Gordan coefficient and related algebra
0053 //
0054 // -------------------------------------------------------------------
0055
0056 #ifndef G4CLEBSCH_HH
0057 #define G4CLEBSCH_HH
0058
0059 #include "globals.hh"
0060 #include <vector>
0061
0062 class G4Clebsch
0063 {
0064 public:
0065   // Calculates the standard Clebsch-Gordan coefficient with Condon-Shortley
0066   // phase convention.
0067   static
0068   G4double ClebschGordanCoeff(G4int twoJ1, G4int twoM1,
0069                   G4int twoJ2, G4int twoM2,
0070                   G4int twoJ);
0071
0072   // Calculates the square of the corresponding Clebsch-Gordan coefficient
0073   static
0074   G4double ClebschGordan(G4int twoJ1, G4int twoM1,
0075              G4int twoJ2, G4int twoM2,
0076              G4int twoJ);
0077
0078   static
0079   std::vector<G4double> GenerateIso3(G4int twoJ1, G4int twoM1,
0080                      G4int twoJ2, G4int twoM2,
0081                      G4int twoJOut1, G4int twoJOut2);
0082
0083   static
0084   G4double Weight(G4int twoJ1, G4int twoM1,
0085           G4int twoJ2, G4int twoM2,
0086           G4int twoJOut1, G4int twoJOut2);
0087
0088   // Deprecated G4double version of Wigner3J that assumes user sent in half-int
0089   // values. Use G4int version instead, which guarantees validity of arguments.
0090   static
0091   G4double Wigner3J(G4double j1, G4double j2, G4double j3,
0092             G4double m1, G4double m2, G4double m3);
0093
0094   // Wigner's 3J symbols (CG-coeffs with a different phase and normalization)
0095   static G4double Wigner3J(G4int twoJ1, G4int twoM1,
0096                            G4int twoJ2, G4int twoM2,
0097                            G4int twoJ3);
0098   static G4double Wigner3J(G4int twoJ1, G4int twoM1,
0099                            G4int twoJ2, G4int twoM2,
0100                            G4int twoJ3, G4int twoM3);
0101
0102   // Calculates the normalized Clebsch-Gordan coefficient, that is the prob
0103   // of isospin decomposition of (J,m) into J1, J2, m1, m2
0104   static
0105   G4double NormalizedClebschGordan(G4int twoJ,  G4int twom,
0106                    G4int twoJ1, G4int twoJ2,
0107                    G4int twom1, G4int twom2);
0108
0109   // Triangle coefficient appearing in explicit calculation of CG-coeffs
0110   static G4double TriangleCoeff(G4int twoA, G4int twoB, G4int twoC);
0111
0112   // Wigner's 6J symbols (generalization of CG's for coupling of 3 angular momenta).
0113   static G4double Wigner6J(G4int twoJ1, G4int twoJ2, G4int twoJ3,
0114                    G4int twoJ4, G4int twoJ5, G4int twoJ6);
0115
0116   // Racah's W Coeffs (6J's with a different phase and normalization)
0117   static G4double RacahWCoeff(G4int twoJ1,  G4int twoJ2,
0118                       G4int twoJ,   G4int twoJ3,
0119                       G4int twoJ12, G4int twoJ23);
0120
0121   // Wigner's 9J symbols (generalization of CG's for coupling of 4 angular momenta).
0122   static G4double Wigner9J(G4int twoJ1, G4int twoJ2, G4int twoJ3,
0123                    G4int twoJ4, G4int twoJ5, G4int twoJ6,
0124                    G4int twoJ7, G4int twoJ8, G4int twoJ9);
0125
0126   // Wigner's little-d matrix
0127   static G4double WignerLittleD(G4int twoJ, G4int twoM, G4int twoN,
0128                 G4double cosTheta);
0129 };
0130
0131 #endif
0132