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G4VGaussianQuadrature.hh
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25 //
26 //
27 // $Id$
28 //
29 // Class description:
30 //
31 // Base Class for realisation of numerical methodes for integration of functions
32 // with signature double f(double) by Gaussian quadrature methods
33 // Roots of ortogonal polynoms and corresponding weights are calculated based on
34 // iteration method (by bisection Newton algorithm). Constant values for initial
35 // approximations were derived from the book: M. Abramowitz, I. Stegun, Handbook
36 // of mathematical functions, DOVER Publications INC, New York 1965 ; chapters 9,
37 // 10, and 22 .
38 //
39 // ---------------------------- Member data: ----------------------------------
40 //
41 // fFunction - pointer to the function to be integrated
42 // fNumber - the number of points in fAbscissa and fWeight arrays
43 // fAbscissa - array of abscissas, where function will be evaluated
44 // fWeight - array of corresponding weights
45 //
46 //
47 // ----------------------------------------------------------------------
48 //
49 // Auxiliary function which returns the value of std::log(gamma-function(x))
50 //
51 // G4double
52 // GammaLogarithm(G4double xx)
53 
54 // ------------------------------------------------------------------------------
55 //
56 // History:
57 // 18.04.97 V.Grichine ( Vladimir.Grichine@cern.ch )
58 
59 #ifndef G4VGAUSSIANQUADRATURE_HH
60 #define G4VGAUSSIANQUADRATURE_HH
61 
62 #include "globals.hh"
63 
64 typedef G4double (*function)(G4double) ;
65 
67 {
68  public:
69 
70  explicit G4VGaussianQuadrature( function pFunction ) ;
71  // Base constructor
72 
73  virtual ~G4VGaussianQuadrature() ;
74  // Virtual destructor
75 
77  G4double GetWeight(G4int index) const ;
78  G4int GetNumber() const;
79  // Access functions
80 
81  protected:
82 
84 
85  // Data members common for GaussianQuadrature family
86  //
87  function fFunction ;
91 
92  private:
93 
96 };
97 
98 #endif