/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2015 OpenFOAM Foundation
-------------------------------------------------------------------------------
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::GammaLimiter

Group
    grpFvLimitedSurfaceInterpolationSchemes

Description
    Class with limiter function which returns the limiter for the
    Gamma differencing scheme based on phict obtained from the LimiterFunc
    class.

    Used in conjunction with the template class LimitedScheme.

SourceFiles
    Gamma.C

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

#ifndef gpuGamma_H
#define gpuGamma_H

#include "vector.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
                        Class GammaLimiter Declaration
\*---------------------------------------------------------------------------*/

template<class LimiterFunc>
class gpuGammaLimiter
:
    public LimiterFunc
{
    scalar k_;

public:

    gpuGammaLimiter(Istream& is)
    :
        k_(readScalar(is))
    {
        if (k_ < 0 || k_ > 1)
        {
            FatalIOErrorInFunction(is)
                << "coefficient = " << k_
                << " should be >= 0 and <= 1"
                << exit(FatalIOError);
        }

        // Rescale k_ to be >= 0 and <= 0.5 (TVD conformant)
        // and avoid the /0 when k_ = 0
        k_ = max(k_/2.0, SMALL);
    }

    __host__ __device__
    scalar limiter
    (
        const scalar cdWeight,
        const scalar faceFlux,
        const typename LimiterFunc::phiType& phiP,
        const typename LimiterFunc::phiType& phiN,
        const typename LimiterFunc::gradPhiType& gradcP,
        const typename LimiterFunc::gradPhiType& gradcN,
        const vector& d
    ) const
    {
        scalar phict = LimiterFunc::phict
        (
            faceFlux, phiP, phiN, gradcP, gradcN, d
        );

        return min(max(phict/k_, 0), 1);
    }
};


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

} // End namespace Foam

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

#endif

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