data/applications/utilities/parallelProcessing/redistributePar/loadOrCreateMesh.C

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2012-2026 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
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
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

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

#include "loadOrCreateMesh.H"
#include "processorPolyPatch.H"
#include "processorCyclicPolyPatch.H"
#include "IOPtrList.H"
#include "OSspecific.H"

// * * * * * * * * * * * * * * * Global Functions  * * * * * * * * * * * * * //

namespace Foam
{
    defineTemplateTypeNameAndDebug(IOPtrList<entry>, 0);
}

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

// Read mesh if available. Otherwise create empty mesh with same non-proc
// patches as proc0 mesh. Requires all processors to have all patches
// (and in same order).
Foam::autoPtr<Foam::fvMesh> Foam::loadOrCreateMesh
(
    const IOobject& io
)
{
    fileName meshSubDir;

    if (io.name() == polyMesh::defaultRegion)
    {
        meshSubDir = polyMesh::meshSubDir;
    }
    else
    {
        meshSubDir = io.name()/polyMesh::meshSubDir;
    }


    // Scatter master patches
    PtrList<entry> patchEntries;
    if (Pstream::master())
    {
        // Read PtrList of dictionary as dictionary.
        const word oldTypeName = IOPtrList<entry>::typeName;
        const_cast<word&>(IOPtrList<entry>::typeName) = word::null;
        IOPtrList<entry> dictList
        (
            IOobject
            (
                "boundary",
                io.time().findInstance
                (
                    meshSubDir,
                    "boundary",
                    IOobject::MUST_READ
                ),
                meshSubDir,
                io.db(),
                IOobject::MUST_READ,
                IOobject::NO_WRITE,
                false
            )
        );
        const_cast<word&>(IOPtrList<entry>::typeName) = oldTypeName;
        // Fake type back to what was in field
        const_cast<word&>(dictList.type()) = dictList.headerClassName();

        patchEntries.transfer(dictList);

        // Send patches
        for
        (
            int slave=Pstream::firstSlave();
            slave<=Pstream::lastSlave();
            slave++
        )
        {
            OPstream toSlave(Pstream::commsTypes::scheduled, slave);
            toSlave << patchEntries;
        }
    }
    else
    {
        // Receive patches
        IPstream fromMaster
        (
            Pstream::commsTypes::scheduled,
            Pstream::masterNo()
        );
        fromMaster >> patchEntries;
    }



    // Check who has a mesh
    const bool haveMesh = fileHandler().isDir
    (
        fileHandler().filePath(io.time().path()/io.instance()/meshSubDir)
    );

    if (!haveMesh)
    {
        bool oldParRun = Pstream::parRun();
        Pstream::parRun() = false;


        // Create dummy mesh. Only used on procs that don't have mesh.
        IOobject noReadIO(io);
        noReadIO.readOpt() = IOobject::NO_READ;
        fvMesh dummyMesh
        (
            noReadIO,
            pointField(),
            faceList(),
            labelList(),
            labelList(),
            false
        );

        // Add patches
        List<polyPatch*> patches(patchEntries.size());
        label nPatches = 0;

        forAll(patchEntries, patchi)
        {
            const entry& e = patchEntries[patchi];
            const word type(e.dict().lookup("type"));
            const word& name = e.keyword();

            if
            (
                type != processorPolyPatch::typeName
             && type != processorCyclicPolyPatch::typeName
            )
            {
                dictionary patchDict(e.dict());
                patchDict.set("nFaces", 0);
                patchDict.set("startFace", 0);

                patches[patchi] = polyPatch::New
                (
                    name,
                    patchDict,
                    nPatches++,
                    dummyMesh.poly().boundary()
                ).ptr();
            }
        }
        patches.setSize(nPatches);
        dummyMesh.addFvPatches(patches, false);  // no parallel comms

        // Add some dummy zones so upon reading it does not read them
        // from the undecomposed case. Should be done as extra argument to
        // regIOobject::readStream?
        List<pointZone*> pz
        (
            1,
            new pointZone
            (
                "dummyPointZone",
                labelList(0),
                dummyMesh.pointZones()
            )
        );
        List<faceZone*> fz
        (
            1,
            new faceZone
            (
                "dummyFaceZone",
                labelList(0),
                boolList(0),
                dummyMesh.faceZones()
            )
        );
        List<cellZone*> cz
        (
            1,
            new cellZone
            (
                "dummyCellZone",
                labelList(0),
                dummyMesh.cellZones()
            )
        );
        dummyMesh.addZones(pz, fz, cz);
        dummyMesh.write();

        Pstream::parRun() = oldParRun;
    }

    autoPtr<fvMesh> meshPtr(new fvMesh(io, false));
    fvMesh& mesh = meshPtr();


    // Sync patches
    // ~~~~~~~~~~~~

    if (!Pstream::master() && haveMesh)
    {
        // Check master names against mine

        const polyBoundaryMesh& patches = mesh.poly().boundary();

        forAll(patchEntries, patchi)
        {
            const entry& e = patchEntries[patchi];
            const word type(e.dict().lookup("type"));
            const word& name = e.keyword();

            if (type == processorPolyPatch::typeName)
            {
                break;
            }

            if (patchi >= patches.size())
            {
                FatalErrorInFunction
                    << "Non-processor patches not synchronised."
                    << endl
                    << "Processor " << Pstream::myProcNo()
                    << " has only " << patches.size()
                    << " patches, master has "
                    << patchi
                    << exit(FatalError);
            }

            if
            (
                type != patches[patchi].type()
             || name != patches[patchi].name()
            )
            {
                FatalErrorInFunction
                    << "Non-processor patches not synchronised."
                    << endl
                    << "Master patch " << patchi
                    << " name:" << type
                    << " type:" << type << endl
                    << "Processor " << Pstream::myProcNo()
                    << " patch " << patchi
                    << " has name:" << patches[patchi].name()
                    << " type:" << patches[patchi].type()
                    << exit(FatalError);
            }
        }
    }


    // Determine zones
    // ~~~~~~~~~~~~~~~

    wordList pointZoneNames(mesh.pointZones().toc());
    Pstream::scatter(pointZoneNames);
    wordList faceZoneNames(mesh.faceZones().toc());
    Pstream::scatter(faceZoneNames);
    wordList cellZoneNames(mesh.cellZones().toc());
    Pstream::scatter(cellZoneNames);

    if (!haveMesh)
    {
        // Add the zones. Make sure to remove the old dummy ones first
        mesh.pointZones().clear();
        mesh.faceZones().clear();
        mesh.cellZones().clear();

        List<pointZone*> pz(pointZoneNames.size());
        forAll(pointZoneNames, i)
        {
            pz[i] = new pointZone
            (
                pointZoneNames[i],
                labelList(0),
                mesh.pointZones()
            );
        }
        List<faceZone*> fz(faceZoneNames.size());
        forAll(faceZoneNames, i)
        {
            fz[i] = new faceZone
            (
                faceZoneNames[i],
                labelList(0),
                boolList(0),
                mesh.faceZones()
            );
        }
        List<cellZone*> cz(cellZoneNames.size());
        forAll(cellZoneNames, i)
        {
            cz[i] = new cellZone
            (
                cellZoneNames[i],
                labelList(0),
                mesh.cellZones()
            );
        }
        mesh.addZones(pz, fz, cz);
    }


    if (!haveMesh)
    {
        // We created a dummy mesh file above. Delete it.
        const fileName meshFiles = io.time().path()/io.instance()/meshSubDir;
        // Pout<< "Removing dummy mesh " << meshFiles << endl;
        mesh.removeFiles();
        rmDir(meshFiles);
    }

    // Force recreation of globalMeshData.
    mesh.clearOut();
    mesh.globalData();


    // Do some checks.

    // Check if the boundary definition is unique
    mesh.poly().boundary().checkDefinition(true);
    // Check if the boundary processor patches are correct
    mesh.poly().boundary().checkParallelSync(true);
    // Check names of zones are equal
    mesh.cellZones().checkDefinition(true);
    mesh.cellZones().checkParallelSync(true);
    mesh.faceZones().checkDefinition(true);
    mesh.faceZones().checkParallelSync(true);
    mesh.pointZones().checkDefinition(true);
    mesh.pointZones().checkParallelSync(true);

    return meshPtr;
}


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