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25 // 25 //
26 // G4SimpleRunge implementation <<
27 // 26 //
28 // Created: W.Wander <wwc@mit.edu>, 12/09/1997 << 27 // $Id: G4SimpleRunge.cc 66356 2012-12-18 09:02:32Z gcosmo $
>> 28 //
>> 29 // Simple Runge:
>> 30 //
>> 31 // x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
>> 32 //
>> 33 // Second order solver.
>> 34 // Takes the derivative at a position to be assumed at the middle of the
>> 35 // Step and adds it to the current position.
>> 36 //
>> 37 //
>> 38 // W.Wander <wwc@mit.edu> 12/09/97
29 // ------------------------------------------- 39 // -------------------------------------------------------------------
30 40
31 #include "G4SimpleRunge.hh" 41 #include "G4SimpleRunge.hh"
32 #include "G4ThreeVector.hh" 42 #include "G4ThreeVector.hh"
33 43
34 ////////////////////////////////////////////// 44 ////////////////////////////////////////////////////////////////
35 // 45 //
36 // Constructor 46 // Constructor
37 // << 47
38 G4SimpleRunge::G4SimpleRunge(G4EquationOfMotio 48 G4SimpleRunge::G4SimpleRunge(G4EquationOfMotion* EqRhs, G4int numberOfVariables)
39 : G4MagErrorStepper(EqRhs, numberOfVariables 49 : G4MagErrorStepper(EqRhs, numberOfVariables),
40 fNumberOfVariables(numberOfVariables) 50 fNumberOfVariables(numberOfVariables)
41 { 51 {
42 52
43 unsigned int noVariables= std::max(numberOf 53 unsigned int noVariables= std::max(numberOfVariables,
44 GetNumbe << 54 GetNumberOfStateVariables());
45 / 55 // To deal with Time >= 7+1
46 dydxTemp = new G4double[noVariables] ; 56 dydxTemp = new G4double[noVariables] ;
47 yTemp = new G4double[noVariables] ; 57 yTemp = new G4double[noVariables] ;
48 } 58 }
49 59
>> 60
50 ////////////////////////////////////////////// 61 /////////////////////////////////////////////////////////////////
51 // 62 //
52 // Destructor 63 // Destructor
53 // << 64
54 G4SimpleRunge::~G4SimpleRunge() 65 G4SimpleRunge::~G4SimpleRunge()
55 { 66 {
56 delete [] dydxTemp; << 67 delete[] dydxTemp;
57 delete [] yTemp; << 68 delete[] yTemp;
58 } 69 }
59 70
60 ////////////////////////////////////////////// 71 //////////////////////////////////////////////////////////////////
61 // 72 //
62 // DumbStepper <<
63 // 73 //
>> 74
64 void 75 void
65 G4SimpleRunge::DumbStepper( const G4double yI 76 G4SimpleRunge::DumbStepper( const G4double yIn[],
66 const G4double dy << 77 const G4double dydx[],
67 G4double h, << 78 G4double h,
68 G4double y << 79 G4double yOut[])
69 { 80 {
70 // Initialise time to t0, needed when it is 81 // Initialise time to t0, needed when it is not updated by the integration.
71 // << 82 yTemp[7] = yOut[7] = yIn[7]; // Better to set it to NaN; // TODO
72 yTemp[7] = yOut[7] = yIn[7]; << 83
>> 84 G4int i;
73 85
74 for( G4int i = 0; i < fNumberOfVariables; ++ << 86 for( i = 0; i < fNumberOfVariables; i++ )
75 { 87 {
76 yTemp[i] = yIn[i] + 0.5 * h*dydx[i] ; 88 yTemp[i] = yIn[i] + 0.5 * h*dydx[i] ;
77 } 89 }
78 90
79 RightHandSide(yTemp,dydxTemp); 91 RightHandSide(yTemp,dydxTemp);
80 92
81 for( G4int i = 0; i < fNumberOfVariables; ++ << 93 for( i = 0; i < fNumberOfVariables; i++ )
82 { 94 {
83 yOut[i] = yIn[i] + h * ( dydxTemp[i] ); 95 yOut[i] = yIn[i] + h * ( dydxTemp[i] );
84 } 96 }
85 } 97 }
86 98