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25 // 25 //
26 // G4GaussChebyshevQ class implementation <<
27 // 26 //
28 // Author: V.Grichine, 13.05.1997 << 27 // $Id$
29 // ------------------------------------------- << 28 //
30 <<
31 #include "G4GaussChebyshevQ.hh" 29 #include "G4GaussChebyshevQ.hh"
32 #include "G4PhysicalConstants.hh" 30 #include "G4PhysicalConstants.hh"
33 31
34 // ------------------------------------------- 32 // -----------------------------------------------------
35 // 33 //
36 // Constructor for Gauss-Chebyshev quadrature 34 // Constructor for Gauss-Chebyshev quadrature method
>> 35
>> 36 G4GaussChebyshevQ::G4GaussChebyshevQ( function pFunction ,
>> 37 G4int nChebyshev )
>> 38 : G4VGaussianQuadrature(pFunction)
>> 39 {
>> 40 fNumber = nChebyshev ; // Try to reduce fNumber twice ??
>> 41 G4double cof = pi/fNumber ;
>> 42 fAbscissa = new G4double[fNumber] ;
>> 43 fWeight = new G4double[fNumber] ;
>> 44 for(G4int i=0;i<fNumber;i++)
>> 45 {
>> 46 fAbscissa[i] = std::cos(cof*(i + 0.5)) ;
>> 47 fWeight[i] = cof*std::sqrt(1 - fAbscissa[i]*fAbscissa[i]) ;
>> 48 }
>> 49 }
>> 50
>> 51 // ----------------------------------------------------------------------
37 // 52 //
38 G4GaussChebyshevQ::G4GaussChebyshevQ(function << 53
39 : G4VGaussianQuadrature(pFunction) << 54 G4GaussChebyshevQ::~G4GaussChebyshevQ()
40 { 55 {
41 fNumber = nChebyshev; // Try to reduce <<
42 G4double cof = pi / fNumber; <<
43 fAbscissa = new G4double[fNumber]; <<
44 fWeight = new G4double[fNumber]; <<
45 for(G4int i = 0; i < fNumber; ++i) <<
46 { <<
47 fAbscissa[i] = std::cos(cof * (i + 0.5)); <<
48 fWeight[i] = cof * std::sqrt(1 - fAbscis <<
49 } <<
50 } 56 }
51 57
52 // ------------------------------------------- 58 // -------------------------------------------------------------------------------
53 // 59 //
54 // Integrates function pointed by fFunction fr << 60 // Integrates function pointed by fFunction from a to b by Gauss-Chebyshev
55 // quadrature method 61 // quadrature method
56 // <<
57 G4double G4GaussChebyshevQ::Integral(G4double <<
58 { <<
59 G4double xDiff = 0.5 * (b - a), xMean = 0.5 <<
60 integral = 0.0; <<
61 62
62 for(G4int i = 0; i < fNumber; ++i) << 63 G4double
63 { << 64 G4GaussChebyshevQ::Integral(G4double a, G4double b) const
64 dx = xDiff * fAbscissa[i]; << 65 {
65 integral += fWeight[i] * fFunction(xMean + << 66 G4double xDiff=0.5*(b - a),
66 } << 67 xMean=0.5*(a + b),
67 return integral *= xDiff; << 68 dx=0.0, integral=0.0 ;
>> 69
>> 70 for(G4int i=0;i<fNumber;i++)
>> 71 {
>> 72 dx = xDiff*fAbscissa[i] ;
>> 73 integral += fWeight[i]*fFunction(xMean + dx) ;
>> 74 }
>> 75 return integral *= xDiff ;
68 } 76 }
69 77