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ODE solvers: further rationalisation and the addition of the Runge-Kutta-Fehlberg method

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This commit is contained in:
Henry
2013-11-02 22:48:13 +00:00
parent 5c2b29b796
commit 489d295448
17 changed files with 623 additions and 270 deletions
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32
applications/test/ODE/Test-ODE.C
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@ -109,8 +109,11 @@ int main(int argc, char *argv[])
// Create the ODE system
testODE ode;
dictionary dict;
dict.add("solver", args[1]);
// Create the selected ODE system solver
autoPtr<ODESolver> odeSolver = ODESolver::New(args[1], ode);
autoPtr<ODESolver> odeSolver = ODESolver::New(ode, dict);
// Initialise the ODE system fields
scalar xStart = 1.0;
@ -124,26 +127,26 @@ int main(int argc, char *argv[])
scalarField dyStart(ode.nEqns());
ode.derivatives(xStart, yStart, dyStart);
Info<< setw(10) << "eps" << setw(12) << "hEst";
Info<< setw(13) << "hDid" << setw(14) << "hNext" << endl;
Info<< setw(10) << "relTol" << setw(12) << "dxEst";
Info<< setw(13) << "dxDid" << setw(14) << "dxNext" << endl;
Info<< setprecision(6);
for (label i=0; i<15; i++)
{
scalar eps = ::Foam::exp(-scalar(i + 1));
scalar relTol = ::Foam::exp(-scalar(i + 1));
scalar x = xStart;
scalarField y(yStart);
scalarField dydx(dyStart);
scalar hEst = 0.6;
scalar hDid, hNext;
scalar dxEst = 0.6;
scalar dxNext = dxEst;
odeSolver->solve(ode, x, y, dydx, eps, hEst, hDid, hNext);
odeSolver->relTol() = relTol;
odeSolver->solve(ode, x, y, dxNext);
Info<< scientific << setw(13) << eps;
Info<< fixed << setw(11) << hEst;
Info<< setw(13) << hDid << setw(13) << hNext
Info<< scientific << setw(13) << relTol;
Info<< fixed << setw(11) << dxEst;
Info<< setw(13) << x - xStart << setw(13) << dxNext
<< setw(13) << y[0] << setw(13) << y[1]
<< setw(13) << y[2] << setw(13) << y[3]
<< endl;
@ -159,12 +162,13 @@ int main(int argc, char *argv[])
yEnd[2] = ::Foam::jn(2, xEnd);
yEnd[3] = ::Foam::jn(3, xEnd);
scalar hEst = 0.5;
scalar dxEst = 0.5;
odeSolver->solve(ode, x, xEnd, y, 1e-4, hEst);
odeSolver->relTol() = 1e-4;
odeSolver->solve(ode, x, xEnd, y, dxEst);
Info<< nl << "Analytical: y(2.0) = " << yEnd << endl;
Info << "Numerical: y(2.0) = " << y << ", hEst = " << hEst << endl;
Info << "Numerical: y(2.0) = " << y << ", dxEst = " << dxEst << endl;
Info<< "\nEnd\n" << endl;