SIBS.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2019 OpenCFD Ltd.
-------------------------------------------------------------------------------
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 <http://www.gnu.org/licenses/>.
 
Class
    Foam::SIBS
 
Group
    grpODESolvers
 
Description
    A semi-implicit mid-point solver for stiff systems of ordinary differential
    equations.
 
    Reference:
    \verbatim
        Bader, G., & Deuflhard, P. (1983).
        A semi-implicit mid-point rule for stiff systems
        of ordinary differential equations.
        Numerische Mathematik, 41(3), 373-398.
    \endverbatim
 
SourceFiles
    SIMPR.C
    polyExtrapolate.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef SIBS_H
#define SIBS_H
 
#include "ODESolver.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                           Class SIBS Declaration
\*---------------------------------------------------------------------------*/
 
class SIBS
:
    public ODESolver
{
    // Private data
 
        static const label kMaxX_ = 7, iMaxX_ = kMaxX_ + 1;
        static const label nSeq_[iMaxX_];
 
        static const scalar safe1, safe2, redMax, redMin, scaleMX;
 
        mutable scalarField a_;
        mutable scalarSquareMatrix alpha_;
        mutable scalarRectangularMatrix d_p_;
        mutable scalarField x_p_;
        mutable scalarField err_;
 
        mutable scalarField yTemp_;
        mutable scalarField ySeq_;
        mutable scalarField yErr_;
        mutable scalarField dydx0_;
        mutable scalarField dfdx_;
        mutable scalarSquareMatrix dfdy_;
 
        mutable label first_, kMax_, kOpt_;
        mutable scalar epsOld_, xNew_;
 
 
    // Private Member Functions
 
        void SIMPR
        (
            const scalar xStart,
            const scalarField& y,
            const scalarField& dydx,
            const scalarField& dfdx,
            const scalarSquareMatrix& dfdy,
            const scalar deltaX,
            const label nSteps,
            scalarField& yEnd
        ) const;
 
        void polyExtrapolate
        (
            const label iest,
            const scalar xest,
            const scalarField& yest,
            scalarField& yz,
            scalarField& dy,
            scalarField& x_p,
            scalarRectangularMatrix& d_p
        ) const;
 
 
public:
 
    //- Runtime type information
    TypeName("SIBS");
 
 
    // Constructors
 
        //- Construct from ODE system
        SIBS(const ODESystem& ode, const dictionary& dict);
 
 
    //- Destructor
    virtual ~SIBS() = default;
 
 
    // Member Functions
 
        //- Resize the ODE solver
        virtual bool resize();
 
        virtual void solve
        (
            scalar& x,
            scalarField& y,
            scalar& dxTry
        ) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //