cellFeatures.C

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    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2019 OpenCFD Ltd.
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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
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\*---------------------------------------------------------------------------*/
 
#include "cellFeatures.H"
#include "primitiveMesh.H"
#include "HashSet.H"
#include "Map.H"
#include "demandDrivenData.H"
#include "ListOps.H"
#include "meshTools.H"
 
// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 
// Return true if edge start and end are on increasing face vertices. (edge is
// guaranteed to be on face)
bool Foam::cellFeatures::faceAlignedEdge(const label facei, const label edgeI)
 const
{
    const edge& e = mesh_.edges()[edgeI];
 
    const face& f = mesh_.faces()[facei];
 
    forAll(f, fp)
    {
        if (f[fp] == e.start())
        {
            label fp1 = f.fcIndex(fp);
 
            return f[fp1] == e.end();
        }
    }
 
    FatalErrorInFunction
        << "Can not find edge " << mesh_.edges()[edgeI]
        << " on face " << facei << abort(FatalError);
 
    return false;
}
 
 
// Return edge in featureEdge that uses vertI and is on same superface
// but is not edgeI
Foam::label Foam::cellFeatures::nextEdge
(
    const Map<label>& toSuperFace,
    const label superFacei,
    const label thisEdgeI,
    const label thisVertI
) const
{
    const labelList& pEdges = mesh_.pointEdges()[thisVertI];
 
    forAll(pEdges, pEdgeI)
    {
        label edgeI = pEdges[pEdgeI];
 
        if ((edgeI != thisEdgeI) && featureEdge_.found(edgeI))
        {
            // Check that edge is used by a face on same superFace
 
            const labelList& eFaces = mesh_.edgeFaces()[edgeI];
 
            forAll(eFaces, eFacei)
            {
                label facei = eFaces[eFacei];
 
                if
                (
                    meshTools::faceOnCell(mesh_, celli_, facei)
                 && (toSuperFace[facei] == superFacei)
                )
                {
                    return edgeI;
                }
            }
        }
    }
 
    FatalErrorInFunction
        << "Can not find edge in " << featureEdge_ << " connected to edge "
        << thisEdgeI << " at vertex " << thisVertI << endl
        << "This might mean that the externalEdges do not form a closed loop"
        << abort(FatalError);
 
    return -1;
}
 
 
// Return true if angle between faces using it is larger than certain value.
bool Foam::cellFeatures::isCellFeatureEdge
(
    const scalar minCos,
    const label edgeI
) const
{
    // Get the two faces using this edge
 
    label face0;
    label face1;
    meshTools::getEdgeFaces(mesh_, celli_, edgeI, face0, face1);
 
    // Check the angle between them by comparing the face normals.
 
    const vector n0 = normalised(mesh_.faceAreas()[face0]);
    const vector n1 = normalised(mesh_.faceAreas()[face1]);
 
    scalar cosAngle = n0 & n1;
 
    const edge& e = mesh_.edges()[edgeI];
 
    const face& f0 = mesh_.faces()[face0];
 
    label face0Start = f0.find(e.start());
    label face0End   = f0.fcIndex(face0Start);
 
    const face& f1 = mesh_.faces()[face1];
 
    label face1Start = f1.find(e.start());
    label face1End   = f1.fcIndex(face1Start);
 
    if
    (
        (
            (f0[face0End] == e.end())
         && (f1[face1End] != e.end())
        )
     || (
            (f0[face0End] != e.end())
         && (f1[face1End] == e.end())
        )
    )
    {
    }
    else
    {
        cosAngle = -cosAngle;
    }
 
    if (cosAngle < minCos)
    {
        return true;
    }
 
    return false;
}
 
 
// Recursively mark (on toSuperFace) all face reachable across non-feature
// edges.
void Foam::cellFeatures::walkSuperFace
(
    const label facei,
    const label superFacei,
    Map<label>& toSuperFace
) const
{
    if (!toSuperFace.found(facei))
    {
        toSuperFace.insert(facei, superFacei);
 
        const labelList& fEdges = mesh_.faceEdges()[facei];
 
        forAll(fEdges, fEdgeI)
        {
            label edgeI = fEdges[fEdgeI];
 
            if (!featureEdge_.found(edgeI))
            {
                label face0;
                label face1;
                meshTools::getEdgeFaces(mesh_, celli_, edgeI, face0, face1);
 
                if (face0 == facei)
                {
                    face0 = face1;
                }
 
                walkSuperFace
                (
                    face0,
                    superFacei,
                    toSuperFace
                );
            }
        }
    }
}
 
 
void Foam::cellFeatures::calcSuperFaces() const
{
    // Determine superfaces by edge walking across non-feature edges
 
    const labelList& cFaces = mesh_.cells()[celli_];
 
    // Mapping from old to super face:
    //    <not found> : not visited
    //    >=0 : superFace
    Map<label> toSuperFace(10*cFaces.size());
 
    label superFacei = 0;
 
    forAll(cFaces, cFacei)
    {
        label facei = cFaces[cFacei];
 
        if (!toSuperFace.found(facei))
        {
            walkSuperFace
            (
                facei,
                superFacei,
                toSuperFace
            );
            superFacei++;
        }
    }
 
    // Construct superFace-to-oldface mapping.
 
    faceMap_.setSize(superFacei);
 
    forAll(cFaces, cFacei)
    {
        label facei = cFaces[cFacei];
 
        faceMap_[toSuperFace[facei]].append(facei);
    }
 
    forAll(faceMap_, superI)
    {
        faceMap_[superI].shrink();
    }
 
 
    // Construct superFaces
 
    facesPtr_ = new faceList(superFacei);
 
    faceList& faces = *facesPtr_;
 
    forAll(cFaces, cFacei)
    {
        label facei = cFaces[cFacei];
 
        label superFacei = toSuperFace[facei];
 
        if (faces[superFacei].empty())
        {
            // Superface not yet constructed.
 
            // Find starting feature edge on face.
            label startEdgeI = -1;
 
            const labelList& fEdges = mesh_.faceEdges()[facei];
 
            forAll(fEdges, fEdgeI)
            {
                label edgeI = fEdges[fEdgeI];
 
                if (featureEdge_.found(edgeI))
                {
                    startEdgeI = edgeI;
 
                    break;
                }
            }
 
 
            if (startEdgeI != -1)
            {
                // Walk point-edge-point along feature edges
 
                DynamicList<label> superFace(10*mesh_.faces()[facei].size());
 
                const edge& e = mesh_.edges()[startEdgeI];
 
                // Walk either start-end or end-start depending on orientation
                // of face. SuperFace will have celli as owner.
                bool flipOrientation =
                    (mesh_.faceOwner()[facei] == celli_)
                  ^ (faceAlignedEdge(facei, startEdgeI));
 
                label startVertI = -1;
 
                if (flipOrientation)
                {
                    startVertI = e.end();
                }
                else
                {
                    startVertI = e.start();
                }
 
                label edgeI = startEdgeI;
 
                label vertI = e.otherVertex(startVertI);
 
                do
                {
                    label newEdgeI = nextEdge
                    (
                        toSuperFace,
                        superFacei,
                        edgeI,
                        vertI
                    );
 
                    // Determine angle between edges.
                    if (isFeaturePoint(edgeI, newEdgeI))
                    {
                        superFace.append(vertI);
                    }
 
                    edgeI = newEdgeI;
 
                    if (vertI == startVertI)
                    {
                        break;
                    }
 
                    vertI = mesh_.edges()[edgeI].otherVertex(vertI);
                }
                while (true);
 
                if (superFace.size() <= 2)
                {
                    WarningInFunction
                        << " Can not collapse faces " << faceMap_[superFacei]
                        << " into one big face on cell " << celli_ << endl
                        << "Try decreasing minCos:" << minCos_ << endl;
                }
                else
                {
                    faces[superFacei].transfer(superFace);
                }
            }
        }
    }
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
// Construct from components
Foam::cellFeatures::cellFeatures
(
    const primitiveMesh& mesh,
    const scalar minCos,
    const label celli
)
:
    mesh_(mesh),
    minCos_(minCos),
    celli_(celli),
    featureEdge_(10*mesh.cellEdges()[celli].size()),
    facesPtr_(nullptr),
    faceMap_(0)
{
    const labelList& cEdges = mesh_.cellEdges()[celli_];
 
    forAll(cEdges, cEdgeI)
    {
        label edgeI = cEdges[cEdgeI];
 
        if (isCellFeatureEdge(minCos_, edgeI))
        {
            featureEdge_.insert(edgeI);
        }
    }
 
}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
Foam::cellFeatures::~cellFeatures()
{
    deleteDemandDrivenData(facesPtr_);
}
 
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
bool Foam::cellFeatures::isFeaturePoint(const label edge0, const label edge1)
 const
{
    if
    (
        (edge0 < 0)
     || (edge0 >= mesh_.nEdges())
     || (edge1 < 0)
     || (edge1 >= mesh_.nEdges())
    )
    {
        FatalErrorInFunction
            << "Illegal edge labels : edge0:" << edge0 << " edge1:" << edge1
            << abort(FatalError);
    }
 
    const edge& e0 = mesh_.edges()[edge0];
 
    const vector e0Vec = e0.unitVec(mesh_.points());
 
    const edge& e1 = mesh_.edges()[edge1];
 
    const vector e1Vec = e1.unitVec(mesh_.points());
 
    scalar cosAngle;
 
    if
    (
        (e0.start() == e1.end())
     || (e0.end() == e1.start())
    )
    {
        // Same direction
        cosAngle = e0Vec & e1Vec;
    }
    else if
    (
        (e0.start() == e1.start())
     || (e0.end() == e1.end())
    )
    {
        // back on back
        cosAngle = - e0Vec & e1Vec;
    }
    else
    {
        cosAngle = GREAT;   // satisfy compiler
 
        FatalErrorInFunction
            << "Edges do not share common vertex. e0:" << e0
            << " e1:" << e1 << abort(FatalError);
    }
 
    if (cosAngle < minCos_)
    {
        // Angle larger than criterion
        return true;
    }
 
    return false;
}
 
 
bool Foam::cellFeatures::isFeatureVertex
(
    const label facei,
    const label vertI
) const
{
    if
    (
        (facei < 0)
     || (facei >= mesh_.nFaces())
     || (vertI < 0)
     || (vertI >= mesh_.nPoints())
    )
    {
        FatalErrorInFunction
            << "Illegal face " << facei << " or vertex " << vertI
            << abort(FatalError);
    }
 
    const labelList& pEdges = mesh_.pointEdges()[vertI];
 
    label edge0 = -1;
    label edge1 = -1;
 
    forAll(pEdges, pEdgeI)
    {
        label edgeI = pEdges[pEdgeI];
 
        if (meshTools::edgeOnFace(mesh_, facei, edgeI))
        {
            if (edge0 == -1)
            {
                edge0 = edgeI;
            }
            else
            {
                edge1 = edgeI;
 
                // Found the two edges.
                break;
            }
        }
    }
 
    if (edge1 == -1)
    {
        FatalErrorInFunction
            << "Did not find two edges sharing vertex " << vertI
            << " on face " << facei << " vertices:" << mesh_.faces()[facei]
            << abort(FatalError);
    }
 
    return isFeaturePoint(edge0, edge1);
}
 
 
// ************************************************************************* //