Trapezoid.C
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25 
26 #include "Trapezoid.H"
28 
29 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
30 
31 namespace Foam
32 {
33  defineTypeNameAndDebug(Trapezoid, 0);
34  addToRunTimeSelectionTable(ODESolver, Trapezoid, dictionary);
35 }
36 
37 
38 // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
39 
41 :
42  ODESolver(ode, dict),
43  adaptiveSolver(ode, dict),
44  err_(n_)
45 {}
46 
47 
48 // * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
49 
51 {
52  if (ODESolver::resize())
53  {
55 
56  resizeField(err_);
57 
58  return true;
59  }
60  else
61  {
62  return false;
63  }
64 }
65 
66 
67 Foam::scalar Foam::Trapezoid::solve
68 (
69  const scalar x0,
70  const scalarField& y0,
71  const label li,
72  const scalarField& dydx0,
73  const scalar dx,
74  scalarField& y
75 ) const
76 {
77  // Predict the state using 1st-order Trapezoid method
78  forAll(y, i)
79  {
80  y[i] = y0[i] + dx*dydx0[i];
81  }
82 
83  // Evaluate the system for the predicted state
84  odes_.derivatives(x0 + dx, y, li, err_);
85 
86  // Update the state as the average between the prediction and the correction
87  // and estimate the error from the difference
88  forAll(y, i)
89  {
90  y[i] = y0[i] + 0.5*dx*(dydx0[i] + err_[i]);
91  err_[i] = 0.5*dx*(err_[i] - dydx0[i]);
92  }
93 
94  return normaliseError(y0, y, err_);
95 }
96 
97 
99 (
100  scalar& x,
101  scalarField& y,
102  const label li,
103  scalar& dxTry
104 ) const
105 {
106  adaptiveSolver::solve(odes_, x, y, li, dxTry);
107 }
108 
109 
110 // ************************************************************************* //
dictionary dict
#define forAll(list, i)
Loop across all elements in list.
Definition: UList.H:434
Abstract base class for the systems of ordinary differential equations.
Definition: ODESystem.H:46
virtual bool resize()=0
Resize the ODE solver.
Definition: ODESolver.C:89
A list of keyword definitions, which are a keyword followed by any number of values (e...
Definition: dictionary.H:156
virtual void derivatives(const scalar x, const scalarField &y, const label li, scalarField &dydx) const =0
Calculate the derivatives in dydx.
An ODE solver for chemistry.
Definition: ode.H:50
scalar normaliseError(const scalarField &y0, const scalarField &y, const scalarField &err) const
Return the normalised scalar error.
Definition: ODESolver.C:40
Macros for easy insertion into run-time selection tables.
bool resize(const label n)
Resize the ODE solver.
const ODESystem & odes_
Reference to ODESystem.
Definition: ODESolver.H:58
virtual scalar solve(const scalar x0, const scalarField &y0, const label li, const scalarField &dydx0, const scalar dx, scalarField &y) const
Solve a single step dx and return the error.
Definition: Trapezoid.C:68
addToRunTimeSelectionTable(ensightPart, ensightPartCells, istream)
defineTypeNameAndDebug(combustionModel, 0)
Abstract base-class for ODE system solvers.
Definition: ODESolver.H:50
static void resizeField(UList< Type > &f, const label n)
Definition: ODESolverI.H:48
Trapezoid(const ODESystem &ode, const dictionary &dict)
Construct from ODESystem.
Definition: Trapezoid.C:40
virtual scalar solve(const scalar x0, const scalarField &y0, const label li, const scalarField &dydx0, const scalar dx, scalarField &y) const =0
Solve a single step dx and return the error.
label n_
Size of the ODESystem (adjustable)
Definition: ODESolver.H:64
virtual bool resize()
Resize the ODE solver.
Definition: Trapezoid.C:50
Namespace for OpenFOAM.