/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
-------------------------------------------------------------------------------
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/>.

Application
    decomposePar

Group
    grpParallelUtilities

Description
    Automatically decomposes a mesh and fields of a case for parallel
    execution of OpenFOAM.

Usage
    \b decomposePar [OPTION]

    Options:
      - \par -cellDist
        Write the cell distribution as a labelList, for use with 'manual'
        decomposition method or as a volScalarField for post-processing.

      - \par -region \<regionName\>
        Decompose named region. Does not check for existence of processor*.

      - \par -allRegions
        Decompose all regions in regionProperties. Does not check for
        existence of processor*.

      - \par -copyZero
        Copy \a 0 directory to processor* rather than decompose the fields.

      - \par -copyUniform
        Copy any \a uniform directories too.

      - \par -constant

      - \par -time xxx:yyy
        Override controlDict settings and decompose selected times. Does not
        re-decompose the mesh i.e. does not handle moving mesh or changing
        mesh cases.

      - \par -fields
        Use existing geometry decomposition and convert fields only.

      - \par -noSets
        Skip decomposing cellSets, faceSets, pointSets.

      - \par -force
        Remove any existing \a processor subdirectories before decomposing the
        geometry.

      - \par -ifRequired
        Only decompose the geometry if the number of domains has changed from a
        previous decomposition. No \a processor subdirectories will be removed
        unless the \a -force option is also specified. This option can be used
        to avoid redundant geometry decomposition (eg, in scripts), but should
        be used with caution when the underlying (serial) geometry or the
        decomposition method etc. have been changed between decompositions.

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

#include "OSspecific.H"
#include "fvCFD.H"
#include "IOobjectList.H"
#include "domainDecomposition.H"
#include "labelIOField.H"
#include "labelFieldIOField.H"
#include "scalarIOField.H"
#include "scalarFieldIOField.H"
#include "vectorIOField.H"
#include "vectorFieldIOField.H"
#include "sphericalTensorIOField.H"
#include "sphericalTensorFieldIOField.H"
#include "symmTensorIOField.H"
#include "symmTensorFieldIOField.H"
#include "tensorIOField.H"
#include "tensorFieldIOField.H"
#include "pointFields.H"
#include "regionProperties.H"

#include "readFields.H"
#include "dimFieldDecomposer.H"
#include "fvFieldDecomposer.H"
#include "pointFieldDecomposer.H"
#include "lagrangianFieldDecomposer.H"
#include "decompositionModel.H"
#include "collatedFileOperation.H"

#include "faCFD.H"
#include "emptyFaPatch.H"
#include "faMeshDecomposition.H"
#include "faFieldDecomposer.H"

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

namespace Foam
{

const labelIOList& procAddressing
(
    const PtrList<fvMesh>& procMeshList,
    const label proci,
    const word& name,
    PtrList<labelIOList>& procAddressingList
)
{
    const fvMesh& procMesh = procMeshList[proci];

    if (!procAddressingList.set(proci))
    {
        procAddressingList.set
        (
            proci,
            new labelIOList
            (
                IOobject
                (
                    name,
                    procMesh.facesInstance(),
                    procMesh.meshSubDir,
                    procMesh,
                    IOobject::MUST_READ,
                    IOobject::NO_WRITE,
                    false
                )
            )
        );
    }
    return procAddressingList[proci];
}


void decomposeUniform
(
    const bool copyUniform,
    const domainDecomposition& mesh,
    const Time& processorDb,
    const word& regionDir = word::null
)
{
    const Time& runTime = mesh.time();

    // Any uniform data to copy/link?
    const fileName uniformDir(regionDir/"uniform");

    if (fileHandler().isDir(runTime.timePath()/uniformDir))
    {
        Info<< "Detected additional non-decomposed files in "
            << runTime.timePath()/uniformDir
            << endl;

        const fileName timePath =
            fileHandler().filePath(processorDb.timePath());

        // If no fields have been decomposed the destination
        // directory will not have been created so make sure.
        mkDir(timePath);

        if (copyUniform || mesh.distributed())
        {
            if (!fileHandler().exists(timePath/uniformDir))
            {
                fileHandler().cp
                (
                    runTime.timePath()/uniformDir,
                    timePath/uniformDir
                );
            }
        }
        else
        {
            // Link with relative paths
            string parentPath = string("..")/"..";

            if (regionDir != word::null)
            {
                parentPath = parentPath/"..";
            }

            fileName currentDir(cwd());
            chDir(timePath);

            if (!fileHandler().exists(uniformDir))
            {
                fileHandler().ln
                (
                    parentPath/runTime.timeName()/uniformDir,
                    uniformDir
                );
            }
            chDir(currentDir);
        }
    }
}

}


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

int main(int argc, char *argv[])
{
    argList::addNote
    (
        "decompose a mesh and fields of a case for parallel execution"
    );

    argList::noParallel();
    argList::addOption
    (
        "decomposeParDict",
        "file",
        "read decomposePar dictionary from specified location"
    );
    #include "addRegionOption.H"
    argList::addBoolOption
    (
        "allRegions",
        "operate on all regions in regionProperties"
    );
    argList::addBoolOption
    (
        "cellDist",
        "write cell distribution as a labelList - for use with 'manual' "
        "decomposition method or as a volScalarField for post-processing."
    );
    argList::addBoolOption
    (
        "copyZero",
        "Copy \a 0 directory to processor* rather than decompose the fields"
    );
    argList::addBoolOption
    (
        "copyUniform",
        "copy any uniform/ directories too"
    );
    argList::addBoolOption
    (
        "fields",
        "use existing geometry decomposition and convert fields only"
    );
    argList::addBoolOption
    (
        "noSets",
        "skip decomposing cellSets, faceSets, pointSets"
    );
    argList::addBoolOption
    (
        "force",
        "remove existing processor*/ subdirs before decomposing the geometry"
    );
    argList::addBoolOption
    (
        "ifRequired",
        "only decompose geometry if the number of domains has changed"
    );

    // Include explicit constant options, have zero from time range
    timeSelector::addOptions(true, false);

    #include "setRootCase.H"

    const bool optRegion        = args.found("region");
    const bool allRegions       = args.found("allRegions");
    const bool writeCellDist    = args.found("cellDist");
    const bool copyZero         = args.found("copyZero");
    const bool copyUniform      = args.found("copyUniform");
    const bool decomposeSets    = !args.found("noSets");
    const bool ifRequiredDecomposition = args.found("ifRequired");

    bool decomposeFieldsOnly = args.found("fields");
    bool forceOverwrite      = args.found("force");


    // Set time from database
    #include "createTime.H"
    // Allow override of time
    instantList times = timeSelector::selectIfPresent(runTime, args);


    // Allow override of decomposeParDict location
    fileName decompDictFile;
    args.readIfPresent("decomposeParDict", decompDictFile);

    wordList regionNames;
    if (allRegions)
    {
        Info<< "Decomposing all regions in regionProperties" << nl << endl;
        regionProperties rp(runTime);

        wordHashSet names;
        forAllConstIters(rp, iter)
        {
            names.insertMany(iter.object());
        }

        regionNames = names.sortedToc();
    }
    else
    {
        regionNames = {fvMesh::defaultRegion};
        args.readIfPresent("region", regionNames[0]);
    }

    forAll(regionNames, regioni)
    {
        const word& regionName = regionNames[regioni];
        const word& regionDir =
            regionName == fvMesh::defaultRegion ? word::null : regionName;

        Info<< "\n\nDecomposing mesh " << regionName << nl << endl;

        // Determine the existing processor count directly
        label nProcs = fileHandler().nProcs(runTime.path(), regionDir);

        // Get requested numberOfSubdomains directly from the dictionary.
        // Note: have no mesh yet so cannot use decompositionModel::New
        const label nDomains = decompositionMethod::nDomains
        (
            IOdictionary
            (
                decompositionModel::selectIO
                (
                    IOobject
                    (
                        "decomposeParDict",
                        runTime.time().system(),
                        regionDir,          // use region if non-standard
                        runTime,
                        IOobject::MUST_READ,
                        IOobject::NO_WRITE,
                        false
                    ),
                    decompDictFile
                )
            )
        );

        if (decomposeFieldsOnly)
        {
            // Sanity check on previously decomposed case
            if (nProcs != nDomains)
            {
                FatalErrorInFunction
                    << "Specified -fields, but the case was decomposed with "
                    << nProcs << " domains"
                    << nl
                    << "instead of " << nDomains
                    << " domains as specified in decomposeParDict" << nl
                    << exit(FatalError);
            }
        }
        else if (nProcs)
        {
            bool procDirsProblem = true;

            if (ifRequiredDecomposition && nProcs == nDomains)
            {
                // we can reuse the decomposition
                decomposeFieldsOnly = true;
                procDirsProblem = false;
                forceOverwrite = false;

                Info<< "Using existing processor directories" << nl;
            }

            if (allRegions || optRegion)
            {
                procDirsProblem = false;
                forceOverwrite = false;
            }

            if (forceOverwrite)
            {
                Info<< "Removing " << nProcs
                    << " existing processor directories" << endl;

                fileHandler().rmDir
                (
                    runTime.path()/word("processors"),
                    true  // silent (may not have been collated)
                );

                // remove existing processor dirs
                // reverse order to avoid gaps if someone interrupts the process
                for (label proci = nProcs-1; proci >= 0; --proci)
                {
                    fileName procDir
                    (
                        runTime.path()/(word("processor") + name(proci))
                    );

                    fileHandler().rmDir(procDir);
                }

                procDirsProblem = false;
            }

            if (procDirsProblem)
            {
                FatalErrorInFunction
                    << "Case is already decomposed with " << nProcs
                    << " domains, use the -force option or manually" << nl
                    << "remove processor directories before decomposing. e.g.,"
                    << nl
                    << "    rm -rf " << runTime.path().c_str() << "/processor*"
                    << nl
                    << exit(FatalError);
            }
        }

        Info<< "Create mesh" << endl;
        domainDecomposition mesh
        (
            IOobject
            (
                regionName,
                runTime.timeName(),
                runTime,
                IOobject::NO_READ,
                IOobject::NO_WRITE,
                false
            ),
            decompDictFile
        );

        // Decompose the mesh
        if (!decomposeFieldsOnly)
        {
            // Disable buffering when writing mesh since we need to read
            // it later on when decomposing the fields
            float bufSz =
                fileOperations::collatedFileOperation::maxThreadFileBufferSize;
            fileOperations::collatedFileOperation::maxThreadFileBufferSize = 0;

            mesh.decomposeMesh();

            mesh.writeDecomposition(decomposeSets);

            if (writeCellDist)
            {
                const labelList& procIds = mesh.cellToProc();

                // Write the decomposition as labelList for use with 'manual'
                // decomposition method.
                labelIOList cellDecomposition
                (
                    IOobject
                    (
                        "cellDecomposition",
                        mesh.facesInstance(),
                        mesh,
                        IOobject::NO_READ,
                        IOobject::NO_WRITE,
                        false
                    ),
                    procIds
                );
                cellDecomposition.write();

                Info<< nl << "Wrote decomposition to "
                    << cellDecomposition.objectPath()
                    << " for use in manual decomposition." << endl;

                // Write as volScalarField for postprocessing.
                volScalarField cellDist
                (
                    IOobject
                    (
                        "cellDist",
                        runTime.timeName(),
                        mesh,
                        IOobject::NO_READ,
                        IOobject::AUTO_WRITE
                    ),
                    mesh,
                    dimensionedScalar("cellDist", dimless, -1),
                    zeroGradientFvPatchScalarField::typeName
                );

                forAll(procIds, celli)
                {
                   cellDist[celli] = procIds[celli];
                }

                cellDist.correctBoundaryConditions();
                cellDist.write();

                Info<< nl << "Wrote decomposition as volScalarField to "
                    << cellDist.name() << " for use in postprocessing."
                    << endl;
            }

            fileOperations::collatedFileOperation::maxThreadFileBufferSize =
                bufSz;
        }


        if (copyZero)
        {
            // Copy the 0 directory into each of the processor directories
            fileName prevTimePath;
            for (label proci = 0; proci < mesh.nProcs(); ++proci)
            {
                Time processorDb
                (
                    Time::controlDictName,
                    args.rootPath(),
                    args.caseName()/fileName(word("processor") + name(proci))
                );
                processorDb.setTime(runTime);

                if (fileHandler().isDir(runTime.timePath()))
                {
                    // Get corresponding directory name (to handle processors/)
                    const fileName timePath
                    (
                        fileHandler().objectPath
                        (
                            IOobject
                            (
                                "",
                                processorDb.timeName(),
                                processorDb
                            ),
                            word::null
                        )
                    );

                    if (timePath != prevTimePath)
                    {
                        Info<< "Processor " << proci
                            << ": copying " << runTime.timePath() << nl
                            << " to " << timePath << endl;
                        fileHandler().cp(runTime.timePath(), timePath);

                        prevTimePath = timePath;
                    }
                }
            }
        }
        else
        {
            // Decompose the field files

            // Cached processor meshes and maps. These are only preserved if
            // running with multiple times.
            PtrList<Time> processorDbList(mesh.nProcs());
            PtrList<fvMesh> procMeshList(mesh.nProcs());
            PtrList<labelIOList> faceProcAddressingList(mesh.nProcs());
            PtrList<labelIOList> cellProcAddressingList(mesh.nProcs());
            PtrList<labelIOList> boundaryProcAddressingList(mesh.nProcs());
            PtrList<fvFieldDecomposer> fieldDecomposerList(mesh.nProcs());
            PtrList<dimFieldDecomposer> dimFieldDecomposerList(mesh.nProcs());
            PtrList<labelIOList> pointProcAddressingList(mesh.nProcs());
            PtrList<pointFieldDecomposer> pointFieldDecomposerList
            (
                mesh.nProcs()
            );


            // Loop over all times
            forAll(times, timeI)
            {
                runTime.setTime(times[timeI], timeI);

                Info<< "Time = " << runTime.timeName() << endl;

                // Search for list of objects for this time
                IOobjectList objects(mesh, runTime.timeName());


                // Construct the vol fields
                // ~~~~~~~~~~~~~~~~~~~~~~~~
                PtrList<volScalarField> volScalarFields;
                readFields(mesh, objects, volScalarFields, false);
                PtrList<volVectorField> volVectorFields;
                readFields(mesh, objects, volVectorFields, false);
                PtrList<volSphericalTensorField> volSphericalTensorFields;
                readFields(mesh, objects, volSphericalTensorFields, false);
                PtrList<volSymmTensorField> volSymmTensorFields;
                readFields(mesh, objects, volSymmTensorFields, false);
                PtrList<volTensorField> volTensorFields;
                readFields(mesh, objects, volTensorFields, false);


                // Construct the dimensioned fields
                // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                PtrList<DimensionedField<scalar, volMesh>> dimScalarFields;
                readFields(mesh, objects, dimScalarFields);
                PtrList<DimensionedField<vector, volMesh>> dimVectorFields;
                readFields(mesh, objects, dimVectorFields);
                PtrList<DimensionedField<sphericalTensor, volMesh>>
                    dimSphericalTensorFields;
                readFields(mesh, objects, dimSphericalTensorFields);
                PtrList<DimensionedField<symmTensor, volMesh>>
                    dimSymmTensorFields;
                readFields(mesh, objects, dimSymmTensorFields);
                PtrList<DimensionedField<tensor, volMesh>> dimTensorFields;
                readFields(mesh, objects, dimTensorFields);


                // Construct the surface fields
                // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                PtrList<surfaceScalarField> surfaceScalarFields;
                readFields(mesh, objects, surfaceScalarFields, false);
                PtrList<surfaceVectorField> surfaceVectorFields;
                readFields(mesh, objects, surfaceVectorFields, false);
                PtrList<surfaceSphericalTensorField>
                    surfaceSphericalTensorFields;
                readFields(mesh, objects, surfaceSphericalTensorFields, false);
                PtrList<surfaceSymmTensorField> surfaceSymmTensorFields;
                readFields(mesh, objects, surfaceSymmTensorFields, false);
                PtrList<surfaceTensorField> surfaceTensorFields;
                readFields(mesh, objects, surfaceTensorFields, false);


                // Construct the point fields
                // ~~~~~~~~~~~~~~~~~~~~~~~~~~
                const pointMesh& pMesh = pointMesh::New(mesh);

                PtrList<pointScalarField> pointScalarFields;
                readFields(pMesh, objects, pointScalarFields, false);
                PtrList<pointVectorField> pointVectorFields;
                readFields(pMesh, objects, pointVectorFields, false);
                PtrList<pointSphericalTensorField> pointSphericalTensorFields;
                readFields(pMesh, objects, pointSphericalTensorFields, false);
                PtrList<pointSymmTensorField> pointSymmTensorFields;
                readFields(pMesh, objects, pointSymmTensorFields, false);
                PtrList<pointTensorField> pointTensorFields;
                readFields(pMesh, objects, pointTensorFields, false);


                // Construct the Lagrangian fields
                // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                fileNameList cloudDirs
                (
                    fileHandler().readDir
                    (
                        runTime.timePath()/cloud::prefix,
                        fileName::DIRECTORY
                    )
                );

                // Particles
                PtrList<Cloud<indexedParticle>> lagrangianPositions
                (
                    cloudDirs.size()
                );
                // Particles per cell
                PtrList<List<SLList<indexedParticle*>*>> cellParticles
                (
                    cloudDirs.size()
                );

                PtrList<PtrList<labelIOField>> lagrangianLabelFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<labelFieldCompactIOField>>
                lagrangianLabelFieldFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<scalarIOField>> lagrangianScalarFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<scalarFieldCompactIOField>>
                lagrangianScalarFieldFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<vectorIOField>> lagrangianVectorFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<vectorFieldCompactIOField>>
                lagrangianVectorFieldFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<sphericalTensorIOField>>
                lagrangianSphericalTensorFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<sphericalTensorFieldCompactIOField>>
                    lagrangianSphericalTensorFieldFields(cloudDirs.size());
                PtrList<PtrList<symmTensorIOField>> lagrangianSymmTensorFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<symmTensorFieldCompactIOField>>
                lagrangianSymmTensorFieldFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<tensorIOField>> lagrangianTensorFields
                (
                    cloudDirs.size()
                );
                PtrList<PtrList<tensorFieldCompactIOField>>
                lagrangianTensorFieldFields
                (
                    cloudDirs.size()
                );

                label cloudI = 0;

                for (const fileName& cloudDir : cloudDirs)
                {
                    IOobjectList sprayObjs
                    (
                        mesh,
                        runTime.timeName(),
                        cloud::prefix/cloudDir,
                        IOobject::MUST_READ,
                        IOobject::NO_WRITE,
                        false
                    );

                    // Note: looking up "positions" for backwards compatibility
                    IOobject* positionsPtr =
                        sprayObjs.lookup(word("positions"));
                    IOobject* coordsPtr = sprayObjs.lookup(word("coordinates"));

                    if (positionsPtr || coordsPtr)
                    {
                        // Read lagrangian particles
                        // ~~~~~~~~~~~~~~~~~~~~~~~~~

                        Info<< "Identified lagrangian data set: "
                            << cloudDir << endl;

                        lagrangianPositions.set
                        (
                            cloudI,
                            new Cloud<indexedParticle>
                            (
                                mesh,
                                cloudDir,
                                false
                            )
                        );


                        // Sort particles per cell
                        // ~~~~~~~~~~~~~~~~~~~~~~~

                        cellParticles.set
                        (
                            cloudI,
                            new List<SLList<indexedParticle*>*>
                            (
                                mesh.nCells(),
                                static_cast<SLList<indexedParticle*>*>(nullptr)
                            )
                        );

                        label i = 0;

                        forAllIter
                        (
                            Cloud<indexedParticle>,
                            lagrangianPositions[cloudI],
                            iter
                        )
                        {
                            iter().index() = i++;

                            label celli = iter().cell();

                            // Check
                            if (celli < 0 || celli >= mesh.nCells())
                            {
                                FatalErrorInFunction
                                    << "Illegal cell number " << celli
                                    << " for particle with index "
                                    << iter().index()
                                    << " at position "
                                    << iter().position() << nl
                                    << "Cell number should be between 0 and "
                                    << mesh.nCells()-1 << nl
                                    << "On this mesh the particle should"
                                    << " be in cell "
                                    << mesh.findCell(iter().position())
                                    << exit(FatalError);
                            }

                            if (!cellParticles[cloudI][celli])
                            {
                                cellParticles[cloudI][celli] =
                                    new SLList<indexedParticle*>();
                            }

                            cellParticles[cloudI][celli]->append(&iter());
                        }

                        // Read fields
                        // ~~~~~~~~~~~

                        IOobjectList lagrangianObjects
                        (
                            mesh,
                            runTime.timeName(),
                            cloud::prefix/cloudDirs[cloudI],
                            IOobject::MUST_READ,
                            IOobject::NO_WRITE,
                            false
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianLabelFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianLabelFieldFields
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianScalarFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianScalarFieldFields
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianVectorFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianVectorFieldFields
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianSphericalTensorFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianSphericalTensorFieldFields
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianSymmTensorFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianSymmTensorFieldFields
                        );

                        lagrangianFieldDecomposer::readFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianTensorFields
                        );

                        lagrangianFieldDecomposer::readFieldFields
                        (
                            cloudI,
                            lagrangianObjects,
                            lagrangianTensorFieldFields
                        );

                        cloudI++;
                    }
                }

                lagrangianPositions.setSize(cloudI);
                cellParticles.setSize(cloudI);
                lagrangianLabelFields.setSize(cloudI);
                lagrangianLabelFieldFields.setSize(cloudI);
                lagrangianScalarFields.setSize(cloudI);
                lagrangianScalarFieldFields.setSize(cloudI);
                lagrangianVectorFields.setSize(cloudI);
                lagrangianVectorFieldFields.setSize(cloudI);
                lagrangianSphericalTensorFields.setSize(cloudI);
                lagrangianSphericalTensorFieldFields.setSize(cloudI);
                lagrangianSymmTensorFields.setSize(cloudI);
                lagrangianSymmTensorFieldFields.setSize(cloudI);
                lagrangianTensorFields.setSize(cloudI);
                lagrangianTensorFieldFields.setSize(cloudI);

                Info<< endl;

                // split the fields over processors
                for (label proci = 0; proci < mesh.nProcs(); ++proci)
                {
                    Info<< "Processor " << proci << ": field transfer" << endl;


                    // open the database
                    if (!processorDbList.set(proci))
                    {
                        processorDbList.set
                        (
                            proci,
                            new Time
                            (
                                Time::controlDictName,
                                args.rootPath(),
                                args.caseName()
                               /fileName(word("processor") + name(proci))
                            )
                        );
                    }
                    Time& processorDb = processorDbList[proci];


                    processorDb.setTime(runTime);

                    // read the mesh
                    if (!procMeshList.set(proci))
                    {
                        procMeshList.set
                        (
                            proci,
                            new fvMesh
                            (
                                IOobject
                                (
                                    regionName,
                                    processorDb.timeName(),
                                    processorDb
                                )
                            )
                        );
                    }
                    const fvMesh& procMesh = procMeshList[proci];

                    const labelIOList& faceProcAddressing = procAddressing
                    (
                        procMeshList,
                        proci,
                        "faceProcAddressing",
                        faceProcAddressingList
                    );

                    const labelIOList& cellProcAddressing = procAddressing
                    (
                        procMeshList,
                        proci,
                        "cellProcAddressing",
                        cellProcAddressingList
                    );

                    const labelIOList& boundaryProcAddressing = procAddressing
                    (
                        procMeshList,
                        proci,
                        "boundaryProcAddressing",
                        boundaryProcAddressingList
                    );


                    // FV fields
                    {
                        if (!fieldDecomposerList.set(proci))
                        {
                            fieldDecomposerList.set
                            (
                                proci,
                                new fvFieldDecomposer
                                (
                                    mesh,
                                    procMesh,
                                    faceProcAddressing,
                                    cellProcAddressing,
                                    boundaryProcAddressing
                                )
                            );
                        }
                        const fvFieldDecomposer& fieldDecomposer =
                            fieldDecomposerList[proci];

                        fieldDecomposer.decomposeFields(volScalarFields);
                        fieldDecomposer.decomposeFields(volVectorFields);
                        fieldDecomposer.decomposeFields
                        (
                            volSphericalTensorFields
                        );
                        fieldDecomposer.decomposeFields(volSymmTensorFields);
                        fieldDecomposer.decomposeFields(volTensorFields);

                        fieldDecomposer.decomposeFields(surfaceScalarFields);
                        fieldDecomposer.decomposeFields(surfaceVectorFields);
                        fieldDecomposer.decomposeFields
                        (
                            surfaceSphericalTensorFields
                        );
                        fieldDecomposer.decomposeFields
                        (
                            surfaceSymmTensorFields
                        );
                        fieldDecomposer.decomposeFields(surfaceTensorFields);

                        if (times.size() == 1)
                        {
                            // Clear cached decomposer
                            fieldDecomposerList.set(proci, nullptr);
                        }
                    }

                    // Dimensioned fields
                    {
                        if (!dimFieldDecomposerList.set(proci))
                        {
                            dimFieldDecomposerList.set
                            (
                                proci,
                                new dimFieldDecomposer
                                (
                                    mesh,
                                    procMesh,
                                    faceProcAddressing,
                                    cellProcAddressing
                                )
                            );
                        }
                        const dimFieldDecomposer& dimDecomposer =
                            dimFieldDecomposerList[proci];

                        dimDecomposer.decomposeFields(dimScalarFields);
                        dimDecomposer.decomposeFields(dimVectorFields);
                        dimDecomposer.decomposeFields(dimSphericalTensorFields);
                        dimDecomposer.decomposeFields(dimSymmTensorFields);
                        dimDecomposer.decomposeFields(dimTensorFields);

                        if (times.size() == 1)
                        {
                            dimFieldDecomposerList.set(proci, nullptr);
                        }
                    }


                    // Point fields
                    if
                    (
                        pointScalarFields.size()
                     || pointVectorFields.size()
                     || pointSphericalTensorFields.size()
                     || pointSymmTensorFields.size()
                     || pointTensorFields.size()
                    )
                    {
                        const labelIOList& pointProcAddressing = procAddressing
                        (
                            procMeshList,
                            proci,
                            "pointProcAddressing",
                            pointProcAddressingList
                        );

                        const pointMesh& procPMesh = pointMesh::New(procMesh);

                        if (!pointFieldDecomposerList.set(proci))
                        {
                            pointFieldDecomposerList.set
                            (
                                proci,
                                new pointFieldDecomposer
                                (
                                    pMesh,
                                    procPMesh,
                                    pointProcAddressing,
                                    boundaryProcAddressing
                                )
                            );
                        }
                        const pointFieldDecomposer& pointDecomposer =
                            pointFieldDecomposerList[proci];

                        pointDecomposer.decomposeFields(pointScalarFields);
                        pointDecomposer.decomposeFields(pointVectorFields);
                        pointDecomposer.decomposeFields
                        (
                            pointSphericalTensorFields
                        );
                        pointDecomposer.decomposeFields(pointSymmTensorFields);
                        pointDecomposer.decomposeFields(pointTensorFields);


                        if (times.size() == 1)
                        {
                            pointProcAddressingList.set(proci, nullptr);
                            pointFieldDecomposerList.set(proci, nullptr);
                        }
                    }


                    // If there is lagrangian data write it out
                    forAll(lagrangianPositions, cloudI)
                    {
                        if (lagrangianPositions[cloudI].size())
                        {
                            lagrangianFieldDecomposer fieldDecomposer
                            (
                                mesh,
                                procMesh,
                                faceProcAddressing,
                                cellProcAddressing,
                                cloudDirs[cloudI],
                                lagrangianPositions[cloudI],
                                cellParticles[cloudI]
                            );

                            // Lagrangian fields
                            {
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianLabelFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianLabelFieldFields[cloudI]
                                );
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianScalarFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianScalarFieldFields[cloudI]
                                );
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianVectorFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianVectorFieldFields[cloudI]
                                );
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianSphericalTensorFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianSphericalTensorFieldFields[cloudI]
                                );
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianSymmTensorFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianSymmTensorFieldFields[cloudI]
                                );
                                fieldDecomposer.decomposeFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianTensorFields[cloudI]
                                );
                                fieldDecomposer.decomposeFieldFields
                                (
                                    cloudDirs[cloudI],
                                    lagrangianTensorFieldFields[cloudI]
                                );
                            }
                        }
                    }

                    // Decompose the "uniform" directory in the time region
                    // directory
                    decomposeUniform(copyUniform, mesh, processorDb, regionDir);

                    // For a multi-region case, also decompose the "uniform"
                    // directory in the time directory
                    if (regionNames.size() > 1 && regioni == 0)
                    {
                        decomposeUniform(copyUniform, mesh, processorDb);
                    }

                    // We have cached all the constant mesh data for the current
                    // processor. This is only important if running with
                    // multiple times, otherwise it is just extra storage.
                    if (times.size() == 1)
                    {
                        boundaryProcAddressingList.set(proci, nullptr);
                        cellProcAddressingList.set(proci, nullptr);
                        faceProcAddressingList.set(proci, nullptr);
                        procMeshList.set(proci, nullptr);
                        processorDbList.set(proci, nullptr);
                    }
                }

                // Finite area mesh and field decomposition

                IOobject faMeshBoundaryIOobj
                (
                    "faBoundary",
                    mesh.time().findInstance
                    (
                        mesh.dbDir()/polyMesh::meshSubDir,
                        "boundary"
                    ),
                    faMesh::meshSubDir,
                    mesh,
                    IOobject::READ_IF_PRESENT,
                    IOobject::NO_WRITE
                );


                if (faMeshBoundaryIOobj.typeHeaderOk<faBoundaryMesh>(true))
                {
                    Info << "\nFinite area mesh decomposition" << endl;

                    faMeshDecomposition aMesh(mesh);

                    aMesh.decomposeMesh();

                    aMesh.writeDecomposition();


                    // Construct the area fields
                    // ~~~~~~~~~~~~~~~~~~~~~~~~
                    PtrList<areaScalarField> areaScalarFields;
                    readFields(aMesh, objects, areaScalarFields);

                    PtrList<areaVectorField> areaVectorFields;
                    readFields(aMesh, objects, areaVectorFields);

                    PtrList<areaSphericalTensorField> areaSphericalTensorFields;
                    readFields(aMesh, objects, areaSphericalTensorFields);

                    PtrList<areaSymmTensorField> areaSymmTensorFields;
                    readFields(aMesh, objects, areaSymmTensorFields);

                    PtrList<areaTensorField> areaTensorFields;
                    readFields(aMesh, objects, areaTensorFields);


                    // Construct the edge fields
                    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                    PtrList<edgeScalarField> edgeScalarFields;
                    readFields(aMesh, objects, edgeScalarFields);

                    Info << endl;

                    // Split the fields over processors
                    for (label procI = 0; procI < mesh.nProcs(); procI++)
                    {
                        Info<< "Processor " << procI
                            << ": finite area field transfer" << endl;

                        // open the database
                        Time processorDb
                        (
                            Time::controlDictName,
                            args.rootPath(),
                            args.caseName()/
                            fileName(word("processor") + name(procI))
                        );

                        processorDb.setTime(runTime);

                        // Read the mesh
                        fvMesh procFvMesh
                        (
                            IOobject
                            (
                                regionName,
                                processorDb.timeName(),
                                processorDb
                            )
                        );

                        faMesh procMesh(procFvMesh);

                        // // Does not work.  HJ, 15/Aug/2017
                        // const labelIOList& faceProcAddressing =
                        //     procAddressing
                        //     (
                        //         procMeshList,
                        //         procI,
                        //         "faceProcAddressing",
                        //         faceProcAddressingList
                        //     );

                        // const labelIOList& boundaryProcAddressing =
                        //     procAddressing
                        //     (
                        //         procMeshList,
                        //         procI,
                        //         "boundaryProcAddressing",
                        //         boundaryProcAddressingList
                        //     );

                        labelIOList faceProcAddressing
                        (
                            IOobject
                            (
                                "faceProcAddressing",
                                "constant",
                                procMesh.meshSubDir,
                                procFvMesh,
                                IOobject::MUST_READ,
                                IOobject::NO_WRITE
                            )
                        );

                        labelIOList boundaryProcAddressing
                        (
                            IOobject
                            (
                                "boundaryProcAddressing",
                                "constant",
                                procMesh.meshSubDir,
                                procFvMesh,
                                IOobject::MUST_READ,
                                IOobject::NO_WRITE
                            )
                        );

                        // FA fields
                        if
                        (
                            areaScalarFields.size()
                         || areaVectorFields.size()
                         || areaSphericalTensorFields.size()
                         || areaSymmTensorFields.size()
                         || areaTensorFields.size()
                         || edgeScalarFields.size()
                        )
                        {
                            labelIOList edgeProcAddressing
                            (
                                IOobject
                                (
                                    "edgeProcAddressing",
                                    "constant",
                                    procMesh.meshSubDir,
                                    procFvMesh,
                                    IOobject::MUST_READ,
                                    IOobject::NO_WRITE
                                )
                            );

                            faFieldDecomposer fieldDecomposer
                            (
                                aMesh,
                                procMesh,
                                edgeProcAddressing,
                                faceProcAddressing,
                                boundaryProcAddressing
                            );

                            fieldDecomposer.decomposeFields(areaScalarFields);
                            fieldDecomposer.decomposeFields(areaVectorFields);
                            fieldDecomposer.decomposeFields(areaSphericalTensorFields);
                            fieldDecomposer.decomposeFields(areaSymmTensorFields);
                            fieldDecomposer.decomposeFields(areaTensorFields);

                            fieldDecomposer.decomposeFields(edgeScalarFields);
                        }
                    }
                }
            }
        }
    }

    Info<< "\nEnd\n" << endl;

    return 0;
}


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