parLagrangianDistributor.C

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    Copyright (C) 2015 OpenFOAM Foundation
    Copyright (C) 2015-2022 OpenCFD Ltd.
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    This file is part of OpenFOAM.

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#include "ListOps.H"
#include "parLagrangianDistributor.H"
#include "passivePositionParticleCloud.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

int Foam::parLagrangianDistributor::verbose_ = 1;


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::parLagrangianDistributor::parLagrangianDistributor
(
    const fvMesh& srcMesh,
    const fvMesh& tgtMesh,
    const label nSrcCells,
    const mapDistributePolyMesh& distMap
)
:
    srcMesh_(srcMesh),
    tgtMesh_(tgtMesh),
    distMap_(distMap)
{
    const mapDistribute& cellMap = distMap_.cellMap();

    // Get destination processors and cells
    destinationProcID_ = labelList(tgtMesh_.nCells(), Pstream::myProcNo());
    cellMap.reverseDistribute(nSrcCells, destinationProcID_);

    destinationCell_ = identity(tgtMesh_.nCells());
    cellMap.reverseDistribute(nSrcCells, destinationCell_);
}


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

// Find all clouds (on all processors) and for each cloud all the objects.
// Result will be synchronised on all processors
void Foam::parLagrangianDistributor::findClouds
(
    const fvMesh& mesh,
    wordList& cloudNames,
    List<wordList>& objectNames
)
{
    fileNameList localCloudDirs
    (
        readDir
        (
            mesh.time().timePath()
          / mesh.dbDir()
          / cloud::prefix,
            fileName::DIRECTORY
        )
    );

    cloudNames.setSize(localCloudDirs.size());
    forAll(localCloudDirs, i)
    {
        cloudNames[i] = localCloudDirs[i];
    }

    // Synchronise cloud names
    Pstream::combineReduce(cloudNames, ListOps::uniqueEqOp<word>());
    Foam::sort(cloudNames);  // Consistent order

    objectNames.clear();
    objectNames.resize(cloudNames.size());

    for (const fileName& localCloudName : localCloudDirs)
    {
        // Do local scan for valid cloud objects
        IOobjectList localObjs
        (
            mesh,
            mesh.time().timeName(),
            cloud::prefix/localCloudName
        );

        bool isCloud = false;
        if (localObjs.erase("coordinates"))
        {
            isCloud = true;
        }
        if (localObjs.erase("positions"))
        {
            isCloud = true;
        }

        if (isCloud)
        {
            // Has coordinates/positions - so must be a valid cloud

            const label cloudi = cloudNames.find(localCloudName);

            objectNames[cloudi] = localObjs.sortedNames();
        }
    }

    // Synchronise objectNames (per cloud)
    for (wordList& objNames : objectNames)
    {
        Pstream::combineReduce(objNames, ListOps::uniqueEqOp<word>());
        Foam::sort(objNames);  // Consistent order
    }
}


Foam::autoPtr<Foam::mapDistributeBase>
Foam::parLagrangianDistributor::distributeLagrangianPositions
(
    passivePositionParticleCloud& lpi
) const
{
    //Debug(lpi.size());

    const label oldLpi = lpi.size();

    labelListList subMap;

    // Allocate transfer buffers
    PstreamBuffers pBufs(Pstream::commsTypes::nonBlocking);

    {
        // List of lists of particles to be transferred for all of the
        // neighbour processors
        List<IDLList<passivePositionParticle>> particleTransferLists
        (
            Pstream::nProcs()
        );

        // Per particle the destination processor
        labelList destProc(lpi.size());

        label particleI = 0;
        for (passivePositionParticle& ppi : lpi)
        {
            const label destProcI = destinationProcID_[ppi.cell()];
            const label destCellI = destinationCell_[ppi.cell()];

            ppi.cell() = destCellI;
            destProc[particleI++] = destProcI;
            particleTransferLists[destProcI].append(lpi.remove(&ppi));
        }


        // Per processor the indices of the particles to send
        subMap = invertOneToMany(Pstream::nProcs(), destProc);


        // Stream into send buffers
        forAll(particleTransferLists, procI)
        {
            //Pout<< "To proc " << procI << " sending "
            //    << particleTransferLists[procI] << endl;
            if (particleTransferLists[procI].size())
            {
                UOPstream particleStream(procI, pBufs);
                particleStream << particleTransferLists[procI];
            }
        }
    }


    // Start sending
    pBufs.finishedSends();


    {
        // Temporarily rename original cloud so we can construct a new one
        // (to distribute the positions) without getting a duplicate
        // registration warning
        const word cloudName = lpi.name();
        lpi.rename(cloudName + "_old");

        // New cloud on tgtMesh
        passivePositionParticleCloud lagrangianPositions
        (
            tgtMesh_,
            cloudName,
            IDLList<passivePositionParticle>()
        );

        // Retrieve from receive buffers
        for (const int proci : pBufs.allProcs())
        {
            //Pout<< "Receive from processor" << proci << " : "
            //    << pBufs.recvDataCount(proci) << endl;

            if (pBufs.recvDataCount(proci))
            {
                UIPstream particleStream(proci, pBufs);

                // Receive particles and locate them
                IDLList<passivePositionParticle> newParticles
                (
                    particleStream,
                    passivePositionParticle::iNew(tgtMesh_)
                );

                for (passivePositionParticle& newp : newParticles)
                {
                    lagrangianPositions.addParticle(newParticles.remove(&newp));
                }
            }
        }

        if (lagrangianPositions.size())
        {
            // Write coordinates file
            IOPosition<passivePositionParticleCloud>
            (
                lagrangianPositions
            ).write();

            // Optionally write positions file in v1706 format and earlier
            if (particle::writeLagrangianPositions)
            {
                IOPosition<passivePositionParticleCloud>
                (
                     lagrangianPositions,
                     cloud::geometryType::POSITIONS
                 ).write();
            }
        }
        else if (oldLpi)
        {
            // When running with -overwrite it should also delete the old
            // files. Below works but is not optimal.

            // Remove any existing coordinates
            const fileName oldCoords
            (
                IOPosition<passivePositionParticleCloud>
                (
                    lagrangianPositions
                ).objectPath()
            );
            Foam::rm(oldCoords);

            // Remove any existing positions
            const fileName oldPos
            (
                IOPosition<passivePositionParticleCloud>
                (
                    lagrangianPositions,
                    cloud::geometryType::POSITIONS
                ).objectPath()
            );
            Foam::rm(oldPos);
        }

        // Restore cloud name
        lpi.rename(cloudName);
    }

    // Until now (FEB-2023) we have always used processor ordering for the
    // construct map (whereas mapDistribute has local transfers first),
    // so we'll stick with that for now, but can likely just use the subMap
    // directly with mapDistribute and have it determine the constructMap.

    labelList recvSizes;
    Pstream::exchangeSizes(subMap, recvSizes);

    label constructSize = 0;
    labelListList constructMap(Pstream::nProcs());

    forAll(constructMap, proci)
    {
        const label len = recvSizes[proci];
        constructMap[proci] = identity(len, constructSize);
        constructSize += len;
    }

    return autoPtr<mapDistributeBase>::New
    (
        constructSize,
        std::move(subMap),
        std::move(constructMap)
    );
}


Foam::autoPtr<Foam::mapDistributeBase>
Foam::parLagrangianDistributor::distributeLagrangianPositions
(
    const word& cloudName
) const
{
    // Load cloud and send particle
    passivePositionParticleCloud lpi(srcMesh_, cloudName, false);

    return distributeLagrangianPositions(lpi);
}


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