cellPointWeight.C

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    Copyright (C) 2011-2017 OpenFOAM Foundation
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License
    This file is part of OpenFOAM.
 
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    under the terms of the GNU General Public License as published by
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    (at your option) any later version.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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#include "cellPointWeight.H"
#include "polyMesh.H"
#include "polyMeshTetDecomposition.H"
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
int Foam::cellPointWeight::debug(debug::debugSwitch("cellPointWeight", 0));
 
Foam::scalar Foam::cellPointWeight::tol(SMALL);
 
// * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * * //
 
void Foam::cellPointWeight::findTetrahedron
(
    const polyMesh& mesh,
    const vector& position,
    const label celli
)
{
    if (debug)
    {
        Pout<< nl << "Foam::cellPointWeight::findTetrahedron" << nl
            << "position = " << position << nl
            << "celli = " << celli << endl;
    }
 
    List<tetIndices> cellTets = polyMeshTetDecomposition::cellTetIndices
    (
        mesh,
        celli
    );
 
    const scalar cellVolume = mesh.cellVolumes()[celli];
 
    forAll(cellTets, tetI)
    {
        const tetIndices& tetIs = cellTets[tetI];
 
        // Barycentric coordinates of the position
        scalar det = tetIs.tet(mesh).pointToBarycentric(position, weights_);
 
        if (mag(det/cellVolume) > tol)
        {
            const scalar& u = weights_[0];
            const scalar& v = weights_[1];
            const scalar& w = weights_[2];
 
            if
            (
                (u + tol > 0)
             && (v + tol > 0)
             && (w + tol > 0)
             && (u + v + w < 1 + tol)
            )
            {
 
                faceVertices_ = tetIs.faceTriIs(mesh);
 
                return;
            }
        }
    }
 
    // A suitable point in a tetrahedron was not found, find the
    // nearest.
 
    scalar minNearDist = VGREAT;
 
    label nearestTetI = -1;
 
    forAll(cellTets, tetI)
    {
        const tetIndices& tetIs = cellTets[tetI];
 
        scalar nearDist = tetIs.tet(mesh).nearestPoint(position).distance();
 
        if (nearDist < minNearDist)
        {
            minNearDist = nearDist;
 
            nearestTetI = tetI;
        }
    }
 
    if (debug)
    {
        Pout<< "cellPointWeight::findTetrahedron" << nl
            << "    Tetrahedron search failed; using closest tet to point "
            << position << nl
            << "    cell: "
            << celli << nl
            << endl;
    }
 
 
    const tetIndices& tetIs = cellTets[nearestTetI];
 
    // Barycentric coordinates of the position, ignoring if the
    // determinant is suitable.  If not, the return from barycentric
    // to weights_ is safe.
    weights_ = tetIs.tet(mesh).pointToBarycentric(position);
 
    faceVertices_ = tetIs.faceTriIs(mesh);
}
 
 
void Foam::cellPointWeight::findTriangle
(
    const polyMesh& mesh,
    const vector& position,
    const label facei
)
{
    if (debug)
    {
        Pout<< "\nbool Foam::cellPointWeight::findTriangle" << nl
            << "position = " << position << nl
            << "facei = " << facei << endl;
    }
 
    List<tetIndices> faceTets = polyMeshTetDecomposition::faceTetIndices
    (
        mesh,
        facei,
        mesh.faceOwner()[facei]
    );
 
    const scalar faceAreaSqr = magSqr(mesh.faceAreas()[facei]);
 
    forAll(faceTets, tetI)
    {
        const tetIndices& tetIs = faceTets[tetI];
 
        // Barycentric coordinates of the position
        barycentric2D triWeights;
        const scalar det =
            tetIs.faceTri(mesh).pointToBarycentric(position, triWeights);
 
        if (0.25*mag(det)/faceAreaSqr > tol)
        {
            const scalar& u = triWeights[0];
            const scalar& v = triWeights[1];
 
            if
            (
                (u + tol > 0)
             && (v + tol > 0)
             && (u + v < 1 + tol)
            )
            {
                // Weight[0] is for the cell centre.
                weights_[0] = 0;
                weights_[1] = triWeights[0];
                weights_[2] = triWeights[1];
                weights_[3] = triWeights[2];
 
                faceVertices_ = tetIs.faceTriIs(mesh);
 
                return;
            }
        }
    }
 
    // A suitable point in a triangle was not found, find the nearest.
 
    scalar minNearDist = VGREAT;
 
    label nearestTetI = -1;
 
    forAll(faceTets, tetI)
    {
        const tetIndices& tetIs = faceTets[tetI];
 
        scalar nearDist = tetIs.faceTri(mesh).nearestPoint(position).distance();
 
        if (nearDist < minNearDist)
        {
            minNearDist = nearDist;
 
            nearestTetI = tetI;
        }
    }
 
    if (debug)
    {
        Pout<< "cellPointWeight::findTriangle" << nl
            << "    Triangle search failed; using closest tri to point "
            << position << nl
            << "    face: "
            << facei << nl
            << endl;
    }
 
    const tetIndices& tetIs = faceTets[nearestTetI];
 
    // Barycentric coordinates of the position, ignoring if the
    // determinant is suitable.  If not, the return from barycentric
    // to triWeights is safe.
 
    const barycentric2D triWeights =
        tetIs.faceTri(mesh).pointToBarycentric(position);
 
    // Weight[0] is for the cell centre.
    weights_[0] = 0;
    weights_[1] = triWeights[0];
    weights_[2] = triWeights[1];
    weights_[3] = triWeights[2];
 
    faceVertices_ = tetIs.faceTriIs(mesh);
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
Foam::cellPointWeight::cellPointWeight
(
    const polyMesh& mesh,
    const vector& position,
    const label celli,
    const label facei
)
:
    celli_(celli)
{
    if (facei < 0)
    {
        // Face data not supplied
        findTetrahedron(mesh, position, celli);
    }
    else
    {
        // Face data supplied
        findTriangle(mesh, position, facei);
    }
}
 
 
// ************************************************************************* //