Rosenbrock12.H

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License
    This file is part of OpenFOAM.

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Class
    Foam::Rosenbrock12

Description
    L-stable embedded Rosenbrock ODE solver of order (1)2.

    References:
    \verbatim
        "A second-order Rosenbrock method applied to
         photochemical dispersion problems",
        J. G. Verwer,
        E. J. Spee,
        J. G. Blom,
        W. Hundsdorfer,
        Siam Journal on Scientific Computing 01/1999; 20(4):1456-1480.
    \endverbatim

SourceFiles
    Rosenbrock12.C

\*---------------------------------------------------------------------------*/

#ifndef Rosenbrock12_H
#define Rosenbrock12_H

#include "ODESolver.H"
#include "adaptiveSolver.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

/*---------------------------------------------------------------------------*\
                           Class Rosenbrock12 Declaration
\*---------------------------------------------------------------------------*/

class Rosenbrock12
:
    public ODESolver,
    public adaptiveSolver
{
    // Private data

        mutable scalarField k1_;
        mutable scalarField k2_;
        mutable scalarField err_;
        mutable scalarField dydx_;
        mutable scalarField dfdx_;
        mutable scalarSquareMatrix dfdy_;
        mutable scalarSquareMatrix a_;
        mutable labelList pivotIndices_;

        static const scalar
            a21,
            c21,
            b1, b2,
            gamma,
            c2,
            e1, e2,
            d1, d2;


public:

    //- Runtime type information
    TypeName("Rosenbrock12");


    // Constructors

        //- Construct from ODE
        Rosenbrock12(const ODESystem& ode, const dictionary& dict);


    // Member Functions

        //- Inherit solve from ODESolver
        using ODESolver::solve;

        //- Solve a single step dx and return the error
        scalar solve
        (
            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
        (
            scalar& x,
            scalarField& y,
            scalar& dxTry
        ) const;
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //