LeastSquaresGrad.C

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#include "LeastSquaresGrad.H"
#include "LeastSquaresVectors.H"
#include "gaussGrad.H"
#include "fvMesh.H"
#include "volMesh.H"
#include "extrapolatedCalculatedFvPatchField.H"

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

template<class Type, class Stencil>
Foam::tmp
<
    Foam::GeometricField
    <
        typename Foam::outerProduct<Foam::vector, Type>::type,
        Foam::fvPatchField,
    Foam::volMesh
    >
>
Foam::fv::LeastSquaresGrad<Type, Stencil>::calcGrad
(
    const GeometricField<Type, fvPatchField, volMesh>& vtf,
    const word& name
) const
{
    typedef typename outerProduct<vector, Type>::type GradType;

    const fvMesh& mesh = vtf.mesh();

    // Get reference to least square vectors
    const LeastSquaresVectors<Stencil>& lsv = LeastSquaresVectors<Stencil>::New
    (
        mesh
    );

    tmp<GeometricField<GradType, fvPatchField, volMesh>> tlsGrad
    (
        GeometricField<GradType, fvPatchField, volMesh>::New
        (
            name,
            mesh,
            dimensioned<GradType>
            (
                "zero",
                vtf.dimensions()/dimLength,
                Zero
            ),
            extrapolatedCalculatedFvPatchField<GradType>::typeName
        )
    );
    GeometricField<GradType, fvPatchField, volMesh>& lsGrad = tlsGrad.ref();
    Field<GradType>& lsGradIf = lsGrad;

    const extendedCentredCellToCellStencil& stencil = lsv.stencil();
    const List<List<label>>& stencilAddr = stencil.stencil();
    const List<List<vector>>& lsvs = lsv.vectors();

    // Construct flat version of vtf
    // including all values referred to by the stencil
    List<Type> flatVtf(stencil.map().constructSize(), Zero);

    // Insert internal values
    forAll(vtf, celli)
    {
        flatVtf[celli] = vtf[celli];
    }

    // Insert boundary values
    forAll(vtf.boundaryField(), patchi)
    {
        const fvPatchField<Type>& ptf = vtf.boundaryField()[patchi];

        label nCompact =
            ptf.patch().start()
          - mesh.nInternalFaces()
          + mesh.nCells();

        forAll(ptf, i)
        {
            flatVtf[nCompact++] = ptf[i];
        }
    }

    // Do all swapping to complete flatVtf
    stencil.map().distribute(flatVtf);

    // Accumulate the cell-centred gradient from the
    // weighted least-squares vectors and the flattened field values
    forAll(stencilAddr, celli)
    {
        const labelList& compactCells = stencilAddr[celli];
        const List<vector>& lsvc = lsvs[celli];

        forAll(compactCells, i)
        {
            lsGradIf[celli] += lsvc[i]*flatVtf[compactCells[i]];
        }
    }

    // Correct the boundary conditions
    lsGrad.correctBoundaryConditions();
    gaussGrad<Type>::correctBoundaryConditions(vtf, lsGrad);

    return tlsGrad;
}


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