Foam::motionDiffusivity&
Foam::displacementLaplacianFvMotionSolver::diffusivity()
{
    if (!diffusivityPtr_.valid())
    {
        diffusivityPtr_ = motionDiffusivity::New
        (
            fvMesh_,
            coeffDict().lookup("diffusivity")
        );
    }
    return diffusivityPtr_();
}
Foam::displacementLaplacianFvMotionSolver::displacementLaplacianFvMotionSolver
(
    const polyMesh& mesh,
    const IOdictionary& dict
)
:
    displacementMotionSolver(mesh, dict, typeName),
    fvMotionSolver(mesh),
    cellDisplacement_
    (
        IOobject
        (
            "cellDisplacement",
            mesh.time().timeName(),
            mesh,
            IOobject::READ_IF_PRESENT,
            IOobject::AUTO_WRITE
        ),
        fvMesh_,
        dimensionedVector
        (
            "cellDisplacement",
            pointDisplacement_.dimensions(),
            Zero
        ),
        cellMotionBoundaryTypes<vector>(pointDisplacement_.boundaryField())
    ),
    pointLocation_(nullptr),
    diffusivityPtr_
    (
        motionDiffusivity::New(fvMesh_, coeffDict().lookup("diffusivity"))
    ),
    frozenPointsZone_
    (
        coeffDict().found("frozenPointsZone")
      ? fvMesh_.pointZones().findZoneID(coeffDict().lookup("frozenPointsZone"))
      : -1
    )
{
    IOobject io
    (
        "pointLocation",
        fvMesh_.time().timeName(),
        fvMesh_,
        IOobject::MUST_READ,
        IOobject::AUTO_WRITE
    );

    if (debug)
    {
        Info<< "displacementLaplacianFvMotionSolver:" << nl
            << "    diffusivity       : " << diffusivityPtr_().type() << nl
            << "    frozenPoints zone : " << frozenPointsZone_ << endl;
    }


    if (io.typeHeaderOk<pointVectorField>(true))
    {
        pointLocation_.reset
        (
            new pointVectorField
            (
                io,
                pointMesh::New(fvMesh_)
            )
        );

        if (debug)
        {
            Info<< "displacementLaplacianFvMotionSolver :"
                << " Read pointVectorField "
                << io.name()
                << " to be used for boundary conditions on points."
                << nl
                << "Boundary conditions:"
                << pointLocation_().boundaryField().types() << endl;
        }
    }
}
Foam::displacementLaplacianFvMotionSolver::displacementLaplacianFvMotionSolver
(
    const polyMesh& mesh,
    Istream& msData
)
:
    fvMotionSolver(mesh),
    points0_
    (
        pointIOField
        (
            IOobject
            (
                "points",
                time().constant(),
                polyMesh::meshSubDir,
                mesh,
                IOobject::MUST_READ,
                IOobject::NO_WRITE,
                false
            )
        )
    ),
    pointDisplacement_
    (
        IOobject
        (
            "pointDisplacement",
            fvMesh_.time().timeName(),
            fvMesh_,
            IOobject::MUST_READ,
            IOobject::AUTO_WRITE
        ),
        pointMesh_
    ),
    cellDisplacement_
    (
        IOobject
        (
            "cellDisplacement",
            mesh.time().timeName(),
            mesh,
            IOobject::READ_IF_PRESENT,
            IOobject::AUTO_WRITE
        ),
        fvMesh_,
        dimensionedVector
        (
            "cellDisplacement",
            pointDisplacement_.dimensions(),
            vector::zero
        ),
        cellMotionBoundaryTypes<vector>(pointDisplacement_.boundaryField())
    ),
    pointLocation_(NULL),
    diffusivityPtr_
    (
        motionDiffusivity::New(*this, lookup("diffusivity"))
    ),
    frozenPointsZone_
    (
        found("frozenPointsZone")
      ? fvMesh_.pointZones().findZoneID(lookup("frozenPointsZone"))
      : -1
    )
{
    IOobject io
    (
        "pointLocation",
        fvMesh_.time().timeName(),
        fvMesh_,
        IOobject::MUST_READ,
        IOobject::AUTO_WRITE
    );

    if (debug)
    {
        Info<< "displacementLaplacianFvMotionSolver:" << nl
            << "    diffusivity       : " << diffusivityPtr_().type() << nl
            << "    frozenPoints zone : " << frozenPointsZone_ << endl;
    }


    if (io.headerOk())
    {
        pointLocation_.reset
        (
            new pointVectorField
            (
                io,
                pointMesh_
            )
        );

        if (debug)
        {
            Info<< "displacementLaplacianFvMotionSolver :"
                << " Read pointVectorField "
                << io.name() << " to be used for boundary conditions on points."
                << nl
                << "Boundary conditions:"
                << pointLocation_().boundaryField().types() << endl;
        }
    }
}