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25 //
26 // G4RK547FEq2 implementation
27 //
28 // The Butcher table of the Higham & Hall 5(4)
29 //
30 // 0 |
31 // 2/13 | 2/13
32 // 2/13 | 3/52 9/52
33 // 5/9 | 12955/26244 -15925/8748 1
34 // 3/4 | -10383/52480 13923/10496 -
35 // 1 | 1403/7236 -429/268 7
36 // 1 | 181/2700 0 6
37 //--------------------------------------------
38 // 181/2700 0 6
39 // 11377/154575 0 3
40 //
41 // Author: Dmitry Sorokin, Google Summer of Co
42 // Supervision: John Apostolakis, CERN
43 // -------------------------------------------
44
45 #include "G4RK547FEq2.hh"
46 #include "G4LineSection.hh"
47 #include "G4FieldUtils.hh"
48
49 using namespace field_utils;
50
51 G4RK547FEq2::G4RK547FEq2(G4EquationOfMotion* E
52 : G4MagIntegratorStepper(EqRhs, integrationV
53 {
54 }
55
56 void G4RK547FEq2::makeStep( const G4double yIn
57 const G4double dyd
58 const G4double hst
59 G4double yOu
60 G4double* dy
61 G4double* yE
62 {
63 G4double yTemp[G4FieldTrack::ncompSVEC];
64 for (G4int i=GetNumberOfVariables(); i<Get
65 {
66 yOutput[i] = yTemp[i] = yInput[i];
67 }
68
69 G4double ak2[G4FieldTrack::ncompSVEC],
70 ak3[G4FieldTrack::ncompSVEC],
71 ak4[G4FieldTrack::ncompSVEC],
72 ak5[G4FieldTrack::ncompSVEC],
73 ak6[G4FieldTrack::ncompSVEC];
74
75 const G4double b21 = 2./13.,
76 b31 = 3./52., b32 = 9./52.,
77 b41 = 12955./26244., b42 =
78 b43 = 12350./6561.,
79 b51 = -10383./52480., b52 =
80 b53 = -176553./199424.,
81 b61 = 1403./7236., b62 = -4
82 b64 = -7884./8911., b65
83 b71 = 181./2700., b72 = 0.,
84 b74 = 19683./106400., b
85 b76 = 67./800.;
86
87 const G4double dc1 = b71 - 11377./154575.,
88 dc2 = b72 - 0.,
89 dc3 = b73 - 35378291./10572
90 dc4 = b74 - 343359./1522850
91 dc5 = b75 - 535952./1947645
92 dc6 = b76 - 134./17175.,
93 dc7 = 0. - 1./12.;
94
95 // RightHandSide(yInput, dydx);
96 for(G4int i = 0; i < GetNumberOfVariables(
97 {
98 yTemp[i] = yInput[i] + hstep * b21 * dyd
99 }
100
101 RightHandSide(yTemp, ak2);
102 for(G4int i = 0; i < GetNumberOfVariables(
103 {
104 yTemp[i] = yInput[i] + hstep * (b31 * dy
105 }
106
107 RightHandSide(yTemp, ak3);
108 for(G4int i = 0;i < GetNumberOfVariables()
109 {
110 yTemp[i] = yInput[i] + hstep * (b41 * dy
111 b43 * ak
112 }
113
114 RightHandSide(yTemp, ak4);
115 for(G4int i = 0; i < GetNumberOfVariables(
116 {
117 yTemp[i] = yInput[i] + hstep * (b51 * dy
118 b53 * ak
119 }
120
121 RightHandSide(yTemp, ak5);
122 for(G4int i = 0; i < GetNumberOfVariables(
123 {
124 yTemp[i] = yInput[i] + hstep * (b61 * dy
125 b63 * ak
126 b65 * ak
127 }
128
129 RightHandSide(yTemp, ak6);
130 for(G4int i = 0; i < GetNumberOfVariables(
131 {
132 yOutput[i] = yInput[i] + hstep * (b71 *
133 b73 *
134 b75 *
135 }
136 if ((dydxOutput != nullptr) && (yError !=
137 {
138 RightHandSide(yOutput, dydxOutput);
139 for(G4int i = 0; i < GetNumberOfVariab
140 {
141 yError[i] = hstep * (dc1 * dydx[i] +
142 dc4 * ak4[i] +
143 dc7 * dydxOutpu
144 }
145 }
146 }
147
148 void G4RK547FEq2::Stepper( const G4double yInp
149 const G4double dydx
150 G4double hste
151 G4double yOut
152 G4double yErr
153 {
154 copy(fyIn, yInput);
155 copy(fdydx, dydx);
156 fhstep = hstep;
157
158 makeStep(fyIn, fdydx, fhstep, fyOut, fdydx
159
160 copy(yOutput, fyOut);
161 }
162
163 void G4RK547FEq2::Stepper( const G4double yInp
164 const G4double dydx
165 G4double hste
166 G4double yOut
167 G4double yErr
168 G4double dydx
169 {
170 copy(fyIn, yInput);
171 copy(fdydx, dydx);
172 fhstep = hstep;
173
174 makeStep(fyIn, fdydx, fhstep, fyOut, fdydx
175
176 copy(yOutput, fyOut);
177 copy(dydxOutput, fdydxOut);
178 }
179
180 G4double G4RK547FEq2::DistChord() const
181 {
182 G4double yMid[G4FieldTrack::ncompSVEC];
183 makeStep(fyIn, fdydx, fhstep / 2., yMid);
184
185 const G4ThreeVector begin = makeVector(fyI
186 const G4ThreeVector mid = makeVector(yMid,
187 const G4ThreeVector end = makeVector(fyOut
188
189 return G4LineSection::Distline(mid, begin,
190 }
191