diff --git a/src/ODE/ODESolvers/RKDP45/RKDP45.C b/src/ODE/ODESolvers/RKDP45/RKDP45.C new file mode 100644 index 0000000000..cf319dca8b --- /dev/null +++ b/src/ODE/ODESolvers/RKDP45/RKDP45.C @@ -0,0 +1,176 @@ +/*---------------------------------------------------------------------------*\ + ========= | + \\ / F ield | OpenFOAM: The Open Source CFD Toolbox + \\ / O peration | + \\ / A nd | Copyright (C) 2013 OpenFOAM Foundation + \\/ M anipulation | +------------------------------------------------------------------------------- +License + This file is part of OpenFOAM. + + OpenFOAM is free software: you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + OpenFOAM is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with OpenFOAM. If not, see . + +\*---------------------------------------------------------------------------*/ + +#include "RKDP45.H" +#include "addToRunTimeSelectionTable.H" + +// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * // + +namespace Foam +{ + defineTypeNameAndDebug(RKDP45, 0); + addToRunTimeSelectionTable(ODESolver, RKDP45, dictionary); + +const scalar + RKDP45::c2 = 1.0/5.0, + RKDP45::c3 = 3.0/10.0, + RKDP45::c4 = 4.0/5.0, + RKDP45::c5 = 8.0/9.0, + + RKDP45::a21 = 1.0/5.0, + + RKDP45::a31 = 3.0/40.0, + RKDP45::a32 = 9.0/40.0, + + RKDP45::a41 = 44.0/45.0, + RKDP45::a42 = -56.0/15.0, + RKDP45::a43 = 32.0/9.0, + + RKDP45::a51 = 19372.0/6561.0, + RKDP45::a52 = -25360.0/2187.0, + RKDP45::a53 = 64448.0/6561.0, + RKDP45::a54 = -212.0/729.0, + + RKDP45::a61 = 9017.0/3168.0, + RKDP45::a62 = -355.0/33.0, + RKDP45::a63 = 46732.0/5247.0, + RKDP45::a64 = 49.0/176.0, + RKDP45::a65 = -5103.0/18656.0, + + RKDP45::b1 = 35.0/384.0, + RKDP45::b3 = 500.0/1113.0, + RKDP45::b4 = 125.0/192.0, + RKDP45::b5 = -2187.0/6784.0, + RKDP45::b6 = 11.0/84.0, + + RKDP45::e1 = 5179.0/57600.0 - RKDP45::b1, + RKDP45::e3 = 7571.0/16695.0 - RKDP45::b3, + RKDP45::e4 = 393.0/640.0 - RKDP45::b4, + RKDP45::e5 = -92097.0/339200.0 - RKDP45::b5, + RKDP45::e6 = 187.0/2100.0 - RKDP45::b6, + RKDP45::e7 = 1.0/40.0; +} + + +// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * // + +Foam::RKDP45::RKDP45(const ODESystem& ode, const dictionary& dict) +: + ODESolver(ode, dict), + adaptiveSolver(ode, dict), + yTemp_(n_), + k2_(n_), + k3_(n_), + k4_(n_), + k5_(n_), + k6_(n_), + err_(n_) +{} + + +// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * // + +Foam::scalar Foam::RKDP45::solve +( + const ODESystem& odes, + const scalar x0, + const scalarField& y0, + const scalarField& dydx0, + const scalar dx, + scalarField& y +) const +{ + forAll(yTemp_, i) + { + yTemp_[i] = y0[i] + a21*dx*dydx0[i]; + } + + odes.derivatives(x0 + c2*dx, yTemp_, k2_); + + forAll(yTemp_, i) + { + yTemp_[i] = y0[i] + dx*(a31*dydx0[i] + a32*k2_[i]); + } + + odes.derivatives(x0 + c3*dx, yTemp_, k3_); + + forAll(yTemp_, i) + { + yTemp_[i] = y0[i] + dx*(a41*dydx0[i] + a42*k2_[i] + a43*k3_[i]); + } + + odes.derivatives(x0 + c4*dx, yTemp_, k4_); + + forAll(yTemp_, i) + { + yTemp_[i] = y0[i] + + dx*(a51*dydx0[i] + a52*k2_[i] + a53*k3_[i] + a54*k4_[i]); + } + + odes.derivatives(x0 + c5*dx, yTemp_, k5_); + + forAll(yTemp_, i) + { + yTemp_[i] = y0[i] + + dx + *(a61*dydx0[i] + a62*k2_[i] + a63*k3_[i] + a64*k4_[i] + a65*k5_[i]); + } + + odes.derivatives(x0 + dx, yTemp_, k6_); + + forAll(y, i) + { + y[i] = y0[i] + + dx*(b1*dydx0[i] + b3*k3_[i] + b4*k4_[i] + b5*k5_[i] + b6*k6_[i]); + } + + // Reuse k2_ for the derivative of the new state + odes.derivatives(x0 + dx, y, k2_); + + forAll(err_, i) + { + err_[i] = + dx + *(e1*dydx0[i] + e3*k3_[i] + e4*k4_[i] + e5*k5_[i] + e6*k6_[i] + + e7*k2_[i]); + } + + return normalizeError(y0, y, err_); +} + + +void Foam::RKDP45::solve +( + const ODESystem& odes, + scalar& x, + scalarField& y, + scalar& dxTry +) const +{ + adaptiveSolver::solve(odes, x, y, dxTry); +} + + +// ************************************************************************* // diff --git a/src/ODE/ODESolvers/RKDP45/RKDP45.H b/src/ODE/ODESolvers/RKDP45/RKDP45.H new file mode 100644 index 0000000000..8e7adc2c46 --- /dev/null +++ b/src/ODE/ODESolvers/RKDP45/RKDP45.H @@ -0,0 +1,141 @@ +/*---------------------------------------------------------------------------*\ + ========= | + \\ / F ield | OpenFOAM: The Open Source CFD Toolbox + \\ / O peration | + \\ / A nd | Copyright (C) 2013 OpenFOAM Foundation + \\/ M anipulation | +------------------------------------------------------------------------------- +License + This file is part of OpenFOAM. + + OpenFOAM is free software: you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + OpenFOAM is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with OpenFOAM. If not, see . + +Class + Foam::RKDP45 + +Description + 4/5th Order Dormand–Prince Runge-Kutta ODE solver. + + References: + \verbatim + "A family of embedded Runge-Kutta formulae" + Dormand, J. R., + Prince, P. J., + Journal of Computational and Applied Mathematics, + 6 (1), 1980: pp. 19-26. + + "Solving Ordinary Differential Equations I: Nonstiff Problems, + second edition", + Hairer, E., + Nørsett, S., + Wanner, G., + Springer-Verlag, Berlin. 1993, ISBN 3-540-56670-8. + \endverbatim + +SeeAlso + Foam::RKF45 + Foam::RKCK45 + +SourceFiles + RKDP45.C + +\*---------------------------------------------------------------------------*/ + +#ifndef RKDP45_H +#define RKDP45_H + +#include "ODESolver.H" +#include "adaptiveSolver.H" + +// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // + +namespace Foam +{ + +/*---------------------------------------------------------------------------*\ + Class RKDP45 Declaration +\*---------------------------------------------------------------------------*/ + +class RKDP45 +: + public ODESolver, + public adaptiveSolver +{ + // Private data + + //- RKDP Constants + static const scalar + c2, c3, c4, c5, + a21, a31, a32, a41, a42, a43, a51, a52, a53, a54, + a61, a62, a63, a64, a65, + b1, b3, b4, b5, b6, + e1, e3, e4, e5, e6, e7; + + // Temporary fields + mutable scalarField yTemp_; + mutable scalarField k2_; + mutable scalarField k3_; + mutable scalarField k4_; + mutable scalarField k5_; + mutable scalarField k6_; + + //- Error-estimate field + mutable scalarField err_; + + +public: + + //- Runtime type information + TypeName("RKDP45"); + + + // Constructors + + //- Construct from ODE + RKDP45(const ODESystem& ode, const dictionary& dict); + + + // Member Functions + + //- Solve a single step dx and return the error + scalar solve + ( + const ODESystem& ode, + const scalar x0, + const scalarField& y0, + const scalarField& dydx0, + const scalar dx, + scalarField& y + ) const; + + //- Solve the ODE system and the update the state + void solve + ( + const ODESystem& ode, + scalar& x, + scalarField& y, + scalar& dxTry + ) const; +}; + + +// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // + +} // End namespace Foam + +// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // + +#endif + +// ************************************************************************* //