create3DCellShape.C

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/*---------------------------------------------------------------------------*\
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License
    This file is part of OpenFOAM.

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Description
    Construct a cell shape from face information

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

#include "cellShapeRecognition.H"
#include <OpenFOAM/labelList.H>

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

namespace Foam
{

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

cellShape create3DCellShape
(
    const label cellIndex,
    const labelList& faceLabels,
    const faceList& faces,
    const labelList& owner,
    const labelList& neighbour,
    const label fluentCellModelID
)
{
    // List of pointers to shape models for 3-D shape recognition
    static List<const cellModel*> fluentCellModelLookup
    (
        7,
        reinterpret_cast<const cellModel*>(0)
    );

    fluentCellModelLookup[2] = cellModeller::lookup("tet");
    fluentCellModelLookup[4] = cellModeller::lookup("hex");
    fluentCellModelLookup[5] = cellModeller::lookup("pyr");
    fluentCellModelLookup[6] = cellModeller::lookup("prism");

    static label faceMatchingOrder[7][6] =
    {
        {-1, -1, -1, -1, -1, -1},
        {-1, -1, -1, -1, -1, -1},
        { 0,  1,  2,  3, -1, -1},    // tet
        {-1, -1, -1, -1, -1, -1},
        { 0,  2,  4,  3,  5,  1},    // hex
        { 0,  1,  2,  3,  4, -1},    // pyr
        { 0,  2,  3,  4,  1, -1},    // prism
    };

    const cellModel& curModel = *fluentCellModelLookup[fluentCellModelID];

    // Checking
    if (faceLabels.size() != curModel.nFaces())
    {
        FatalErrorIn
        (
            "create3DCellShape(const label cellIndex, "
            "const labelList& faceLabels, const labelListList& faces, "
            "const labelList& owner, const labelList& neighbour, "
            "const label fluentCellModelID)"
        )   << "Number of face labels not equal to"
            << "number of face in the model. "
            << "Number of face labels: " << faceLabels.size()
            << " number of faces in model: " << curModel.nFaces()
            << abort(FatalError);
    }

    // make a list of outward-pointing faces
    labelListList localFaces(faceLabels.size());

    forAll  (faceLabels, faceI)
    {
        const label curFaceLabel = faceLabels[faceI];

        const labelList& curFace = faces[curFaceLabel];

        if (owner[curFaceLabel] == cellIndex)
        {
            localFaces[faceI] = curFace;
        }
        else if (neighbour[curFaceLabel] == cellIndex)
        {
            // Reverse the face
            localFaces[faceI].setSize(curFace.size());

            forAllReverse(curFace, i)
            {
                localFaces[faceI][curFace.size() - i - 1] =
                    curFace[i];
            }
        }
        else
        {
            FatalErrorIn
            (
                "create3DCellShape(const label cellIndex, "
                "const labelList& faceLabels, const labelListList& faces, "
                "const labelList& owner, const labelList& neighbour, "
                "const label fluentCellModelID)"
            )   << "face " << curFaceLabel
                << " does not belong to cell " << cellIndex
                << ". Face owner: " << owner[curFaceLabel] << " neighbour: "
                << neighbour[curFaceLabel]
                << abort(FatalError);
        }
    }

    // Algorithm:
    // Make an empty list of pointLabels and initialise it with -1. Pick the
    // first face from modelFaces and look through the faces to find one with
    // the same number of labels. Insert face by copying its labels into
    // pointLabels. Mark the face as used. Loop through all model faces.
    // For each model face loop through faces. If the face is unused and the
    // numbers of labels fit, try to match the face onto the point labels. If
    // at least one edge is matched, insert the face into pointLabels. If at
    // any stage the matching algorithm reaches the end of faces, the matching
    // algorithm has failed. Once all the faces are matched, the list of
    // pointLabels defines the model.

    // Make a list of empty pointLabels
    labelList pointLabels(curModel.nPoints(), -1);

    // Follow the used mesh faces
    List<bool> meshFaceUsed(localFaces.size(), false);

    // Get the raw model faces
    const faceList& modelFaces = curModel.modelFaces();

    // Insert the first face into the list
    const labelList& firstModelFace =
        modelFaces[faceMatchingOrder[fluentCellModelID][0]];

    bool found = false;

    forAll (localFaces, meshFaceI)
    {
        if (localFaces[meshFaceI].size() == firstModelFace.size())
        {
            // Match. Insert points into the pointLabels
            found = true;

            const labelList& curMeshFace = localFaces[meshFaceI];

            meshFaceUsed[meshFaceI] = true;

            forAll (curMeshFace, pointI)
            {
                pointLabels[firstModelFace[pointI]] = curMeshFace[pointI];
            }

            break;
        }
    }

    if (!found)
    {
        FatalErrorIn
        (
            "create3DCellShape(const label cellIndex, "
            "const labelList& faceLabels, const labelListList& faces, "
            "const labelList& owner, const labelList& neighbour, "
            "const label fluentCellModelID)"
        )   << "Cannot find match for first face. "
            << "cell model: " << curModel.name() << " first model face: "
            << firstModelFace << " Mesh faces: " << localFaces
            << abort(FatalError);
    }

    for (label modelFaceI = 1; modelFaceI < modelFaces.size(); modelFaceI++)
    {
        // get the next model face
        const labelList& curModelFace =
            modelFaces
            [faceMatchingOrder[fluentCellModelID][modelFaceI]];

        found = false;

        // Loop through mesh faces until a match is found
        forAll (localFaces, meshFaceI)
        {
            if
            (
                !meshFaceUsed[meshFaceI]
             && localFaces[meshFaceI].size() == curModelFace.size()
            )
            {
                // A possible match. A mesh face will be rotated, so make a copy
                labelList meshFaceLabels = localFaces[meshFaceI];

                for
                (
                    label rotation = 0;
                    rotation < meshFaceLabels.size();
                    rotation++
                )
                {
                    // try matching the face
                    label nMatchedLabels = 0;

                    forAll (meshFaceLabels, pointI)
                    {
                        if
                        (
                            pointLabels[curModelFace[pointI]]
                         == meshFaceLabels[pointI]
                        )
                        {
                            nMatchedLabels++;
                        }
                    }

                    if (nMatchedLabels >= 2)
                    {
                        // match!
                        found = true;
                    }

                    if (found)
                    {
                        // match found. Insert mesh face
                        forAll (meshFaceLabels, pointI)
                        {
                            pointLabels[curModelFace[pointI]] =
                                meshFaceLabels[pointI];
                        }

                        meshFaceUsed[meshFaceI] = true;

                        break;
                    }
                    else
                    {
                        // No match found. Rotate face
                        label firstLabel = meshFaceLabels[0];

                        for (label i = 1; i < meshFaceLabels.size(); i++)
                        {
                            meshFaceLabels[i - 1] = meshFaceLabels[i];
                        }

                        meshFaceLabels[meshFaceLabels.size() - 1] = firstLabel;
                    }
                }

                if (found) break;
            }
        }

        if (!found)
        {
            // A model face is not matched. Shape detection failed
            FatalErrorIn
            (
                "create3DCellShape(const label cellIndex, "
                "const labelList& faceLabels, const labelListList& faces, "
                "const labelList& owner, const labelList& neighbour, "
                "const label fluentCellModelID)"
            )   << "Cannot find match for face "
                << modelFaceI
                << ".\nModel: " << curModel.name() << " model face: "
                << curModelFace << " Mesh faces: " << localFaces
                << "Matched points: " << pointLabels
                << abort(FatalError);
        }
    }

    return cellShape(curModel, pointLabels);
}


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

} // End namespace Foam

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