/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 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::cubic

Group
    grpFvSurfaceInterpolationSchemes

Description
    Cubic interpolation scheme class derived from linear and returns
    linear weighting factors but also applies an explicit correction.

SourceFiles
    cubic.C

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

#ifndef cubic_H
#define cubic_H

#include "linear.H"
#include "gaussGrad.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
                           Class cubic Declaration
\*---------------------------------------------------------------------------*/

template<class Type>
class cubic
:
    public linear<Type>
{
    // Private Member Functions

        //- No copy construct
        cubic(const cubic&) = delete;

        //- No copy assignment
        void operator=(const cubic&) = delete;


public:

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


    // Constructors

        //- Construct from mesh
        cubic(const fvMesh& mesh)
        :
            linear<Type>(mesh)
        {}

        //- Construct from mesh and Istream
        cubic
        (
            const fvMesh& mesh,
            Istream&
        )
        :
            linear<Type>(mesh)
        {}

        //- Construct from mesh, faceFlux and Istream
        cubic
        (
            const fvMesh& mesh,
            const surfaceScalarField&,
            Istream&
        )
        :
            linear<Type>(mesh)
        {}


    // Member Functions

        //- Return true if this scheme uses an explicit correction
        virtual bool corrected() const
        {
            return true;
        }

        //- Return the explicit correction to the face-interpolate
        virtual tmp<GeometricField<Type, fvsPatchField, surfaceMesh>>
        correction
        (
            const GeometricField<Type, fvPatchField, volMesh>& vf
        ) const
        {
            const fvMesh& mesh = this->mesh();

            // calculate the appropriate interpolation factors
            const surfaceScalarField& lambda = mesh.weights();

            const surfaceScalarField kSc
            (
                lambda*(scalar(1) - lambda*(scalar(3) - scalar(2)*lambda))
            );

            const surfaceScalarField kVecP(sqr(scalar(1) - lambda)*lambda);
            const surfaceScalarField kVecN(sqr(lambda)*(lambda - scalar(1)));

            tmp<GeometricField<Type, fvsPatchField, surfaceMesh>> tsfCorr
            (
                new GeometricField<Type, fvsPatchField, surfaceMesh>
                (
                    IOobject
                    (
                        "cubic::correction(" + vf.name() +')',
                        mesh.time().timeName(),
                        mesh,
                        IOobject::NO_READ,
                        IOobject::NO_WRITE,
                        IOobject::NO_REGISTER
                    ),
                    surfaceInterpolationScheme<Type>::interpolate(vf, kSc, -kSc)
                )
            );
            GeometricField<Type, fvsPatchField, surfaceMesh>& sfCorr =
                tsfCorr.ref();

            for (direction cmpt=0; cmpt<pTraits<Type>::nComponents; cmpt++)
            {
                sfCorr.replace
                (
                    cmpt,
                    sfCorr.component(cmpt)
                  + (
                        surfaceInterpolationScheme
                        <
                            typename outerProduct
                            <
                                vector,
                                typename pTraits<Type>::cmptType
                            >::type
                        >::interpolate
                        (
                            fv::gaussGrad
                            <typename pTraits<Type>::cmptType>(mesh)
                           .grad(vf.component(cmpt)),
                            kVecP,
                            kVecN
                        ) & mesh.Sf()
                    )/mesh.magSf()/mesh.surfaceInterpolation::deltaCoeffs()
                );
            }

            typename GeometricField<Type, fvsPatchField, surfaceMesh>::
                Boundary& sfCorrbf = sfCorr.boundaryFieldRef();

            forAll(sfCorrbf, pi)
            {
                if (!sfCorrbf[pi].coupled())
                {
                    sfCorrbf[pi] = Zero;
                }
            }

            return tsfCorr;
        }
};


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

} // End namespace Foam

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

#endif

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