snappyRefineDriver.C

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2015 OpenFOAM Foundation
    Copyright (C) 2015-2025 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/>.

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

#include "snappyRefineDriver.H"
#include "meshRefinement.H"
#include "fvMesh.H"
#include "Time.H"
#include "cellSet.H"
#include "syncTools.H"
#include "refinementParameters.H"
#include "refinementSurfaces.H"
#include "refinementFeatures.H"
#include "shellSurfaces.H"
#include "mapDistributePolyMesh.H"
#include "unitConversion.H"
#include "snapParameters.H"
#include "localPointRegion.H"
#include "IOmanip.H"
#include "labelVector.H"
#include "profiling.H"
#include "searchableSurfaces.H"
#include "fvMeshSubset.H"
#include "interpolationTable.H"
#include "snappyVoxelMeshDriver.H"
#include "regionSplit.H"
#include "removeCells.H"
#include "addPatchCellLayer.H"

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

namespace Foam
{
    defineTypeNameAndDebug(snappyRefineDriver, 0);
} // End namespace Foam


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

Foam::snappyRefineDriver::snappyRefineDriver
(
    meshRefinement& meshRefiner,
    decompositionMethod& decomposer,
    fvMeshDistribute& distributor,
    const labelUList& globalToMasterPatch,
    const labelUList& globalToSlavePatch,
    coordSetWriter& setFormatter,
    refPtr<surfaceWriter>& surfFormatter,
    const bool dryRun
)
:
    meshRefiner_(meshRefiner),
    decomposer_(decomposer),
    distributor_(distributor),
    globalToMasterPatch_(globalToMasterPatch),
    globalToSlavePatch_(globalToSlavePatch),
    setFormatter_(setFormatter),
    surfFormatter_(surfFormatter),
    dryRun_(dryRun)
{}


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

Foam::label Foam::snappyRefineDriver::featureEdgeRefine
(
    const refinementParameters& refineParams,
    const label maxIter,
    const label minRefine
)
{
    if (dryRun_)
    {
        return 0;
    }

    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    addProfiling(edge, "snappyHexMesh::refine::edge");
    const fvMesh& mesh = meshRefiner_.mesh();

    label iter = 0;

    if (meshRefiner_.features().size() && maxIter > 0)
    {
        for (; iter < maxIter; iter++)
        {
            Info<< nl
                << "Feature refinement iteration " << iter << nl
                << "------------------------------" << nl
                << endl;

            labelList candidateCells
            (
                meshRefiner_.refineCandidates
                (
                    refineParams.locationsInMesh(),
                    refineParams.curvature(),
                    refineParams.planarAngle(),

                    true,               // featureRefinement
                    false,              // featureDistanceRefinement
                    false,              // internalRefinement
                    false,              // surfaceRefinement
                    false,              // curvatureRefinement
                    false,              // smallFeatureRefinement
                    false,              // gapRefinement
                    false,              // bigGapRefinement
                    false,              // spreadGapSize
                    refineParams.maxGlobalCells(),
                    refineParams.maxLocalCells()
                )
            );
            labelList cellsToRefine
            (
                meshRefiner_.meshCutter().consistentRefinement
                (
                    candidateCells,
                    true
                )
            );
            Info<< "Determined cells to refine in = "
                << mesh.time().cpuTimeIncrement() << " s" << endl;



            const label nCellsToRefine =
                returnReduce(cellsToRefine.size(), sumOp<label>());

            Info<< "Selected for feature refinement : " << nCellsToRefine
                << " cells (out of " << mesh.globalData().nTotalCells()
                << ')' << endl;

            if (nCellsToRefine <= minRefine)
            {
                Info<< "Stopping refining since too few cells selected."
                    << nl << endl;
                break;
            }


            if (debug > 0)
            {
                const_cast<Time&>(mesh.time())++;
            }


            if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
            {
                meshRefiner_.balanceAndRefine
                (
                    "feature refinement iteration " + name(iter),
                    decomposer_,
                    distributor_,
                    cellsToRefine,
                    refineParams.maxLoadUnbalance(),
                    refineParams.maxCellUnbalance()
                );
            }
            else
            {
                meshRefiner_.refineAndBalance
                (
                    "feature refinement iteration " + name(iter),
                    decomposer_,
                    distributor_,
                    cellsToRefine,
                    refineParams.maxLoadUnbalance(),
                    refineParams.maxCellUnbalance()
                );
            }
        }
    }
    return iter;
}


Foam::label Foam::snappyRefineDriver::smallFeatureRefine
(
    const refinementParameters& refineParams,
    const label maxIter
)
{
    if (dryRun_)
    {
        return 0;
    }

    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    addProfiling(feature, "snappyHexMesh::refine::smallFeature");
    const fvMesh& mesh = meshRefiner_.mesh();

    label iter = 0;

    // See if any surface has an extendedGapLevel
    const labelList surfaceMaxLevel(meshRefiner_.surfaces().maxGapLevel());
    const labelList shellMaxLevel(meshRefiner_.shells().maxGapLevel());
    const labelList curvMaxLevel(meshRefiner_.surfaces().maxCurvatureLevel());

    if
    (
        max(surfaceMaxLevel) == 0
     && max(shellMaxLevel) == 0
     && max(curvMaxLevel) == 0
    )
    {
        return iter;
    }

    for (; iter < maxIter; iter++)
    {
        Info<< nl
            << "Small surface feature refinement iteration " << iter << nl
            << "--------------------------------------------" << nl
            << endl;


        // Determine cells to refine
        // ~~~~~~~~~~~~~~~~~~~~~~~~~

        labelList candidateCells
        (
            meshRefiner_.refineCandidates
            (
                refineParams.locationsInMesh(),
                refineParams.curvature(),
                refineParams.planarAngle(),

                false,              // featureRefinement
                false,              // featureDistanceRefinement
                false,              // internalRefinement
                false,              // surfaceRefinement
                false,              // curvatureRefinement
                true,               // smallFeatureRefinement
                false,              // gapRefinement
                false,              // bigGapRefinement
                false,              // spreadGapSize
                refineParams.maxGlobalCells(),
                refineParams.maxLocalCells()
            )
        );

        labelList cellsToRefine
        (
            meshRefiner_.meshCutter().consistentRefinement
            (
                candidateCells,
                true
            )
        );
        Info<< "Determined cells to refine in = "
            << mesh.time().cpuTimeIncrement() << " s" << endl;


        const label nCellsToRefine =
            returnReduce(cellsToRefine.size(), sumOp<label>());

        Info<< "Selected for refinement : " << nCellsToRefine
            << " cells (out of " << mesh.globalData().nTotalCells()
            << ')' << endl;

        // Stop when no cells to refine or have done minimum necessary
        // iterations and not enough cells to refine.
        if (nCellsToRefine == 0)
        {
            Info<< "Stopping refining since too few cells selected."
                << nl << endl;
            break;
        }


        if (debug)
        {
            const_cast<Time&>(mesh.time())++;
        }


        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
        {
            meshRefiner_.balanceAndRefine
            (
                "small feature refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
        else
        {
            meshRefiner_.refineAndBalance
            (
                "small feature refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
    }
    return iter;
}


Foam::label Foam::snappyRefineDriver::surfaceOnlyRefine
(
    const refinementParameters& refineParams,
    const label maxIter,
    const label leakBlockageIter
)
{
    if (dryRun_)
    {
        return 0;
    }

    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    addProfiling(surface, "snappyHexMesh::refine::surface");
    const fvMesh& mesh = meshRefiner_.mesh();
    const refinementSurfaces& surfaces = meshRefiner_.surfaces();

    // Determine the maximum refinement level over all surfaces. This
    // determines the minimum number of surface refinement iterations.
    label overallMaxLevel = max(meshRefiner_.surfaces().maxLevel());

    label iter;
    for (iter = 0; iter < maxIter; iter++)
    {
        Info<< nl
            << "Surface refinement iteration " << iter << nl
            << "------------------------------" << nl
            << endl;


        // Do optional leak closing (by removing cells)
        if (iter >= leakBlockageIter)
        {
            // Block off intersections with unzoned surfaces with specified
            // leakLevel < iter
            const labelList unnamedSurfaces
            (
                surfaceZonesInfo::getUnnamedSurfaces
                (
                    surfaces.surfZones()
                )
            );

            DynamicList<label> selectedSurfaces(unnamedSurfaces.size());
            for (const label surfi : unnamedSurfaces)
            {
                const label regioni = surfaces.globalRegion(surfi, 0);

                // Take shortcut: assume all cells on surface are refined to
                // its refinement level at iteration iter. So just use the
                // iteration to see if the surface is a candidate.
                if (iter > surfaces.leakLevel()[regioni])
                {
                    selectedSurfaces.append(surfi);
                }
            }

            if
            (
                selectedSurfaces.size()
             && refineParams.locationsOutsideMesh().size()
            )
            {
               meshRefiner_.blockLeakFaces
                (
                    globalToMasterPatch_,
                    globalToSlavePatch_,
                    refineParams.locationsInMesh(),
                    refineParams.zonesInMesh(),
                    refineParams.locationsOutsideMesh(),
                    selectedSurfaces
                );
            }
        }


        // Determine cells to refine
        // ~~~~~~~~~~~~~~~~~~~~~~~~~
        // Only look at surface intersections (minLevel and surface curvature),
        // do not do internal refinement (refinementShells)

        labelList candidateCells
        (
            meshRefiner_.refineCandidates
            (
                refineParams.locationsInMesh(),
                refineParams.curvature(),
                refineParams.planarAngle(),

                false,              // featureRefinement
                false,              // featureDistanceRefinement
                false,              // internalRefinement
                true,               // surfaceRefinement
                true,               // curvatureRefinement
                false,              // smallFeatureRefinement
                false,              // gapRefinement
                false,              // bigGapRefinement
                false,              // spreadGapSize
                refineParams.maxGlobalCells(),
                refineParams.maxLocalCells()
            )
        );
        labelList cellsToRefine
        (
            meshRefiner_.meshCutter().consistentRefinement
            (
                candidateCells,
                true
            )
        );
        Info<< "Determined cells to refine in = "
            << mesh.time().cpuTimeIncrement() << " s" << endl;


        const label nCellsToRefine =
            returnReduce(cellsToRefine.size(), sumOp<label>());

        Info<< "Selected for refinement : " << nCellsToRefine
            << " cells (out of " << mesh.globalData().nTotalCells()
            << ')' << endl;

        // Stop when no cells to refine or have done minimum necessary
        // iterations and not enough cells to refine.
        if
        (
            nCellsToRefine == 0
         || (
                iter >= overallMaxLevel
             && nCellsToRefine <= refineParams.minRefineCells()
            )
        )
        {
            Info<< "Stopping refining since too few cells selected."
                << nl << endl;
            break;
        }


        if (debug)
        {
            const_cast<Time&>(mesh.time())++;
        }


        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
        {
            meshRefiner_.balanceAndRefine
            (
                "surface refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
        else
        {
            meshRefiner_.refineAndBalance
            (
                "surface refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
    }
    return iter;
}


Foam::label Foam::snappyRefineDriver::gapOnlyRefine
(
    const refinementParameters& refineParams,
    const label maxIter
)
{
    if (dryRun_)
    {
        return 0;
    }

    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    const fvMesh& mesh = meshRefiner_.mesh();

    // Determine the maximum refinement level over all surfaces. This
    // determines the minimum number of surface refinement iterations.

    label maxIncrement = 0;
    const labelList& maxLevel = meshRefiner_.surfaces().maxLevel();
    const labelList& gapLevel = meshRefiner_.surfaces().gapLevel();

    forAll(maxLevel, i)
    {
        maxIncrement = max(maxIncrement, gapLevel[i]-maxLevel[i]);
    }

    label iter = 0;

    if (maxIncrement == 0)
    {
        return iter;
    }

    for (iter = 0; iter < maxIter; iter++)
    {
        Info<< nl
            << "Gap refinement iteration " << iter << nl
            << "--------------------------" << nl
            << endl;


        // Determine cells to refine
        // ~~~~~~~~~~~~~~~~~~~~~~~~~
        // Only look at surface intersections (minLevel and surface curvature),
        // do not do internal refinement (refinementShells)

        labelList candidateCells
        (
            meshRefiner_.refineCandidates
            (
                refineParams.locationsInMesh(),
                refineParams.curvature(),
                refineParams.planarAngle(),

                false,              // featureRefinement
                false,              // featureDistanceRefinement
                false,              // internalRefinement
                false,              // surfaceRefinement
                false,              // curvatureRefinement
                false,              // smallFeatureRefinement
                true,               // gapRefinement
                false,              // bigGapRefinement
                false,              // spreadGapSize
                refineParams.maxGlobalCells(),
                refineParams.maxLocalCells()
            )
        );

        if (debug&meshRefinement::MESH)
        {
            Pout<< "Writing current mesh to time "
                << meshRefiner_.timeName() << endl;
            meshRefiner_.write
            (
                meshRefinement::debugType(debug),
                meshRefinement::writeType
                (
                    meshRefinement::writeLevel()
                  | meshRefinement::WRITEMESH
                ),
                mesh.time().path()/meshRefiner_.timeName()
            );
            Pout<< "Dumped mesh in = "
                << mesh.time().cpuTimeIncrement() << " s\n" << nl << endl;


            Pout<< "Dumping " << candidateCells.size()
                << " cells to cellSet candidateCellsFromGap." << endl;
            cellSet c(mesh, "candidateCellsFromGap", candidateCells);
            c.instance() = meshRefiner_.timeName();
            c.write();
        }

        // Grow by one layer to make sure we're covering the gap
        {
            boolList isCandidateCell(mesh.nCells(), false);
            forAll(candidateCells, i)
            {
                isCandidateCell[candidateCells[i]] = true;
            }

            for (label i=0; i<1; i++)
            {
                boolList newIsCandidateCell(isCandidateCell);

                // Internal faces
                for (label facei = 0; facei < mesh.nInternalFaces(); facei++)
                {
                    label own = mesh.faceOwner()[facei];
                    label nei = mesh.faceNeighbour()[facei];

                    if (isCandidateCell[own] != isCandidateCell[nei])
                    {
                        newIsCandidateCell[own] = true;
                        newIsCandidateCell[nei] = true;
                    }
                }

                // Get coupled boundary condition values
                boolList neiIsCandidateCell;
                syncTools::swapBoundaryCellList
                (
                    mesh,
                    isCandidateCell,
                    neiIsCandidateCell
                );

                // Boundary faces
                for
                (
                    label facei = mesh.nInternalFaces();
                    facei < mesh.nFaces();
                    facei++
                )
                {
                    label own = mesh.faceOwner()[facei];
                    label bFacei = facei-mesh.nInternalFaces();

                    if (isCandidateCell[own] != neiIsCandidateCell[bFacei])
                    {
                        newIsCandidateCell[own] = true;
                    }
                }

                isCandidateCell.transfer(newIsCandidateCell);
            }

            label n = 0;
            forAll(isCandidateCell, celli)
            {
                if (isCandidateCell[celli])
                {
                    n++;
                }
            }
            candidateCells.setSize(n);
            n = 0;
            forAll(isCandidateCell, celli)
            {
                if (isCandidateCell[celli])
                {
                    candidateCells[n++] = celli;
                }
            }
        }


        if (debug&meshRefinement::MESH)
        {
            Pout<< "Dumping " << candidateCells.size()
                << " cells to cellSet candidateCellsFromGapPlusBuffer." << endl;
            cellSet c(mesh, "candidateCellsFromGapPlusBuffer", candidateCells);
            c.instance() = meshRefiner_.timeName();
            c.write();
        }


        labelList cellsToRefine
        (
            meshRefiner_.meshCutter().consistentRefinement
            (
                candidateCells,
                true
            )
        );
        Info<< "Determined cells to refine in = "
            << mesh.time().cpuTimeIncrement() << " s" << endl;


        const label nCellsToRefine =
            returnReduce(cellsToRefine.size(), sumOp<label>());

        Info<< "Selected for refinement : " << nCellsToRefine
            << " cells (out of " << mesh.globalData().nTotalCells()
            << ')' << endl;

        // Stop when no cells to refine or have done minimum necessary
        // iterations and not enough cells to refine.
        if
        (
            nCellsToRefine == 0
         || (
                iter >= maxIncrement
             && nCellsToRefine <= refineParams.minRefineCells()
            )
        )
        {
            Info<< "Stopping refining since too few cells selected."
                << nl << endl;
            break;
        }


        if (debug)
        {
            const_cast<Time&>(mesh.time())++;
        }


        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
        {
            meshRefiner_.balanceAndRefine
            (
                "gap refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
        else
        {
            meshRefiner_.refineAndBalance
            (
                "gap refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
    }
    return iter;
}


Foam::label Foam::snappyRefineDriver::surfaceProximityBlock
(
    const refinementParameters& refineParams,
    const label maxIter
)
{
    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    fvMesh& mesh = meshRefiner_.mesh();

    if (min(meshRefiner_.surfaces().blockLevel()) == labelMax)
    {
        return 0;
    }

    label iter = 0;

    for (iter = 0; iter < maxIter; iter++)
    {
        Info<< nl
            << "Gap blocking iteration " << iter << nl
            << "------------------------" << nl
            << endl;


        // Determine cells to block
        // ~~~~~~~~~~~~~~~~~~~~~~~~

        meshRefiner_.removeGapCells
        (
            refineParams.planarAngle(),
            meshRefiner_.surfaces().blockLevel(),
            globalToMasterPatch_,
            refineParams.nFilterIter()
        );

        if (debug)
        {
            const_cast<Time&>(mesh.time())++;
            Pout<< "Writing gap blocking iteration "
                << iter << " mesh to time " << meshRefiner_.timeName()
                << endl;
            meshRefiner_.write
            (
                meshRefinement::debugType(debug),
                meshRefinement::writeType
                (
                    meshRefinement::writeLevel()
                  | meshRefinement::WRITEMESH
                ),
                mesh.time().path()/meshRefiner_.timeName()
            );
        }
    }
    return iter;
}


Foam::label Foam::snappyRefineDriver::bigGapOnlyRefine
(
    const refinementParameters& refineParams,
    const bool spreadGapSize,
    const label maxIter
)
{
    if (refineParams.minRefineCells() == -1)
    {
        // Special setting to be able to restart shm on meshes with inconsistent
        // cellLevel/pointLevel
        return 0;
    }

    if (dryRun_)
    {
        return 0;
    }

    const fvMesh& mesh = meshRefiner_.mesh();

    label iter = 0;

    // See if any surface has an extendedGapLevel
    labelList surfaceMaxLevel(meshRefiner_.surfaces().maxGapLevel());
    labelList shellMaxLevel(meshRefiner_.shells().maxGapLevel());

    label overallMaxLevel(max(max(surfaceMaxLevel), max(shellMaxLevel)));

    if (overallMaxLevel == 0)
    {
        return iter;
    }


    for (; iter < maxIter; iter++)
    {
        Info<< nl
            << "Big gap refinement iteration " << iter << nl
            << "------------------------------" << nl
            << endl;


        // Determine cells to refine
        // ~~~~~~~~~~~~~~~~~~~~~~~~~

        labelList candidateCells
        (
            meshRefiner_.refineCandidates
            (
                refineParams.locationsInMesh(),
                refineParams.curvature(),
                refineParams.planarAngle(),

                false,              // featureRefinement
                false,              // featureDistanceRefinement
                false,              // internalRefinement
                false,              // surfaceRefinement
                false,              // curvatureRefinement
                false,              // smallFeatureRefinement
                false,              // gapRefinement
                true,               // bigGapRefinement
                spreadGapSize,      // spreadGapSize
                refineParams.maxGlobalCells(),
                refineParams.maxLocalCells()
            )
        );


        if (debug&meshRefinement::MESH)
        {
            Pout<< "Writing current mesh to time "
                << meshRefiner_.timeName() << endl;
            meshRefiner_.write
            (
                meshRefinement::debugType(debug),
                meshRefinement::writeType
                (
                    meshRefinement::writeLevel()
                  | meshRefinement::WRITEMESH
                ),
                mesh.time().path()/meshRefiner_.timeName()
            );
            Pout<< "Dumped mesh in = "
                << mesh.time().cpuTimeIncrement() << " s\n" << nl << endl;

            Pout<< "Dumping " << candidateCells.size()
                << " cells to cellSet candidateCellsFromBigGap." << endl;
            cellSet c(mesh, "candidateCellsFromBigGap", candidateCells);
            c.instance() = meshRefiner_.timeName();
            c.write();
        }

        labelList cellsToRefine
        (
            meshRefiner_.meshCutter().consistentRefinement
            (
                candidateCells,
                true
            )
        );
        Info<< "Determined cells to refine in = "
            << mesh.time().cpuTimeIncrement() << " s" << endl;


        const label nCellsToRefine =
            returnReduce(cellsToRefine.size(), sumOp<label>());

        Info<< "Selected for refinement : " << nCellsToRefine
            << " cells (out of " << mesh.globalData().nTotalCells()
            << ')' << endl;

        // Stop when no cells to refine or have done minimum necessary
        // iterations and not enough cells to refine.
        if
        (
            nCellsToRefine == 0
         || (
                iter >= overallMaxLevel
             && nCellsToRefine <= refineParams.minRefineCells()
            )
        )
        {
            Info<< "Stopping refining since too few cells selected."
                << nl << endl;
            break;
        }


        if (debug)
        {
            const_cast<Time&>(mesh.time())++;
        }


        if (returnReduceOr(mesh.nCells() >= refineParams.maxLocalCells()))
        {
            meshRefiner_.balanceAndRefine
            (
                "big gap refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
        else
        {
            meshRefiner_.refineAndBalance
            (
                "big gap refinement iteration " + name(iter),
                decomposer_,
                distributor_,
                cellsToRefine,
                refineParams.maxLoadUnbalance(),
                refineParams.maxCellUnbalance()
            );
        }
    }
    return iter;
}