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