SIMPR.C
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25 
26 #include "SIBS.H"
27 
28 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
29 
30 void Foam::SIBS::SIMPR
31 (
32  const scalar xStart,
33  const scalarField& y,
34  const label li,
35  const scalarField& dydx,
36  const scalarField& dfdx,
37  const scalarSquareMatrix& dfdy,
38  const scalar deltaX,
39  const label nSteps,
40  scalarField& yEnd
41 ) const
42 {
43  scalar h = deltaX/nSteps;
44 
45  scalarSquareMatrix a(n_);
46  for (label i=0; i<n_; i++)
47  {
48  for (label j=0; j<n_; j++)
49  {
50  a(i, j) = -h*dfdy(i, j);
51  }
52  ++a(i, i);
53  }
54 
55  labelList pivotIndices(n_);
56  LUDecompose(a, pivotIndices);
57 
58  for (label i=0; i<n_; i++)
59  {
60  yEnd[i] = h*(dydx[i] + h*dfdx[i]);
61  }
62 
63  LUBacksubstitute(a, pivotIndices, yEnd);
64 
65  scalarField del(yEnd);
66  scalarField ytemp(n_);
67 
68  for (label i=0; i<n_; i++)
69  {
70  ytemp[i] = y[i] + del[i];
71  }
72 
73  scalar x = xStart + h;
74 
75  odes_.derivatives(x, ytemp, li, yEnd);
76 
77  for (label nn=2; nn<=nSteps; nn++)
78  {
79  for (label i=0; i<n_; i++)
80  {
81  yEnd[i] = h*yEnd[i] - del[i];
82  }
83 
84  LUBacksubstitute(a, pivotIndices, yEnd);
85 
86  for (label i=0; i<n_; i++)
87  {
88  ytemp[i] += (del[i] += 2.0*yEnd[i]);
89  }
90 
91  x += h;
92 
93  odes_.derivatives(x, ytemp, li, yEnd);
94  }
95  for (label i=0; i<n_; i++)
96  {
97  yEnd[i] = h*yEnd[i] - del[i];
98  }
99 
100  LUBacksubstitute(a, pivotIndices, yEnd);
101 
102  for (label i=0; i<n_; i++)
103  {
104  yEnd[i] += ytemp[i];
105  }
106 }
107 
108 
109 // ************************************************************************* //
FvWallInfoData< WallInfo, label > label
A label is an int32_t or int64_t as specified by the pre-processor macro WM_LABEL_SIZE.
void LUDecompose(scalarSquareMatrix &matrix, labelList &pivotIndices)
LU decompose the matrix with pivoting.
virtual void derivatives(const scalar x, const scalarField &y, const label li, scalarField &dydx) const =0
Calculate the derivatives in dydx.
const dimensionedScalar h
Planck constant.
const ODESystem & odes_
Reference to ODESystem.
Definition: ODESolver.H:58
Field< scalar > scalarField
Specialisation of Field<T> for scalar.
List< label > labelList
A List of labels.
Definition: labelList.H:56
volScalarField scalarField(fieldObject, mesh)
label n_
Size of the ODESystem (adjustable)
Definition: ODESolver.H:64
SquareMatrix< scalar > scalarSquareMatrix
void LUBacksubstitute(const scalarSquareMatrix &luMmatrix, const labelList &pivotIndices, List< Type > &source)
LU back-substitution with given source, returning the solution.