diff --git a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
index eae7f72761..fed03a58f9 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
@@ -900,374 +900,9 @@ void Foam::decompositionMethod::calcCellCells
 }
 
 
-//void Foam::decompositionMethod::calcCellCells
-//(
-//    const polyMesh& mesh,
-//    const boolList& blockedFace,
-//    const List<labelPair>& explicitConnections,
-//    const labelList& agglom,
-//    const label nLocalCoarse,
-//    const bool parallel,
-//    CompactListList<label>& cellCells
-//)
-//{
-//    const labelList& faceOwner = mesh.faceOwner();
-//    const labelList& faceNeighbour = mesh.faceNeighbour();
-//    const polyBoundaryMesh& patches = mesh.boundaryMesh();
-//
-//
-//    // Create global cell numbers
-//    // ~~~~~~~~~~~~~~~~~~~~~~~~~~
-//
-//    globalIndex globalAgglom
-//    (
-//        nLocalCoarse,
-//        Pstream::msgType(),
-//        Pstream::worldComm,
-//        parallel
-//    );
-//
-//
-//    // Get agglomerate owner on other side of coupled faces
-//    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-//
-//    labelList globalNeighbour(mesh.nFaces()-mesh.nInternalFaces());
-//
-//    for (const polyPatch& pp : patches)
-//    {
-//        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
-//        {
-//            label facei = pp.start();
-//            label bFacei = pp.start() - mesh.nInternalFaces();
-//
-//            forAll(pp, i)
-//            {
-//                globalNeighbour[bFacei] = globalAgglom.toGlobal
-//                (
-//                    agglom[faceOwner[facei]]
-//                );
-//
-//                ++facei;
-//                ++bFacei;
-//            }
-//        }
-//    }
-//
-//    // Get the cell on the other side of coupled patches
-//    syncTools::swapBoundaryFaceList(mesh, globalNeighbour);
-//
-//
-//    // Count number of faces (internal + coupled)
-//    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-//
-//    // Number of faces per coarse cell
-//    labelList nFacesPerCell(nLocalCoarse, 0);
-//
-//    // 1. Internal faces
-//    for (label facei = 0; facei < mesh.nInternalFaces(); ++facei)
-//    {
-//        if (!blockedFace[facei])
-//        {
-//            const label own = agglom[faceOwner[facei]];
-//            const label nei = agglom[faceNeighbour[facei]];
-//
-//            nFacesPerCell[own]++;
-//            nFacesPerCell[nei]++;
-//        }
-//    }
-//
-//    // 2. Coupled faces
-//    for (const polyPatch& pp : patches)
-//    {
-//        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
-//        {
-//            label facei = pp.start();
-//            label bFacei = pp.start()-mesh.nInternalFaces();
-//
-//            forAll(pp, i)
-//            {
-//                if (!blockedFace[facei])
-//                {
-//                    const label own = agglom[faceOwner[facei]];
-//                    const label globalNei = globalNeighbour[bFacei];
-//
-//                    if
-//                    (
-//                       !globalAgglom.isLocal(globalNei)
-//                     || globalAgglom.toLocal(globalNei) != own
-//                    )
-//                    {
-//                        nFacesPerCell[own]++;
-//                    }
-//
-//                    ++facei;
-//                    ++bFacei;
-//                }
-//            }
-//        }
-//    }
-//
-//    // 3. Explicit connections between non-coupled boundary faces
-//    forAll(explicitConnections, i)
-//    {
-//        const labelPair& baffle = explicitConnections[i];
-//        label f0 = baffle.first();
-//        label f1 = baffle.second();
-//
-//        if (!blockedFace[f0] && blockedFace[f1])
-//        {
-//            label f0Own = agglom[faceOwner[f0]];
-//            label f1Own = agglom[faceOwner[f1]];
-//
-//            // Always count the connection between the two owner sides
-//            if (f0Own != f1Own)
-//            {
-//                nFacesPerCell[f0Own]++;
-//                nFacesPerCell[f1Own]++;
-//            }
-//
-//            // Add any neighbour side connections
-//            if (mesh.isInternalFace(f0))
-//            {
-//                label f0Nei = agglom[faceNeighbour[f0]];
-//
-//                if (mesh.isInternalFace(f1))
-//                {
-//                    // Internal faces
-//                    label f1Nei = agglom[faceNeighbour[f1]];
-//
-//                    if (f0Own != f1Nei)
-//                    {
-//                        nFacesPerCell[f0Own]++;
-//                        nFacesPerCell[f1Nei]++;
-//                    }
-//                    if (f0Nei != f1Own)
-//                    {
-//                        nFacesPerCell[f0Nei]++;
-//                        nFacesPerCell[f1Own]++;
-//                    }
-//                    if (f0Nei != f1Nei)
-//                    {
-//                        nFacesPerCell[f0Nei]++;
-//                        nFacesPerCell[f1Nei]++;
-//                    }
-//                }
-//                else
-//                {
-//                    // f1 boundary face
-//                    if (f0Nei != f1Own)
-//                    {
-//                        nFacesPerCell[f0Nei]++;
-//                        nFacesPerCell[f1Own]++;
-//                    }
-//                }
-//            }
-//            else
-//            {
-//                if (mesh.isInternalFace(f1))
-//                {
-//                    label f1Nei = agglom[faceNeighbour[f1]];
-//                    if (f0Own != f1Nei)
-//                    {
-//                        nFacesPerCell[f0Own]++;
-//                        nFacesPerCell[f1Nei]++;
-//                    }
-//                }
-//            }
-//        }
-//    }
-//
-//
-//    // Fill in offset and data
-//    // ~~~~~~~~~~~~~~~~~~~~~~~
-//
-//    cellCells.setSize(nFacesPerCell);
-//
-//    nFacesPerCell = 0;
-//
-//    labelList& m = cellCells.m();
-//    const labelList& offsets = cellCells.offsets();
-//
-//    // 1. For internal faces is just offsetted owner and neighbour
-//    for (label facei = 0; facei < mesh.nInternalFaces(); ++facei)
-//    {
-//        if (!blockedFace[facei])
-//        {
-//            label own = agglom[faceOwner[facei]];
-//            label nei = agglom[faceNeighbour[facei]];
-//
-//            m[offsets[own] + nFacesPerCell[own]++] =
-//              globalAgglom.toGlobal(nei);
-//            m[offsets[nei] + nFacesPerCell[nei]++] =
-//              globalAgglom.toGlobal(own);
-//        }
-//    }
-//
-//    // 2. For boundary faces is offsetted coupled neighbour
-//    for (const polyPatch& pp : patches)
-//    {
-//        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
-//        {
-//            label facei = pp.start();
-//            label bFacei = pp.start()-mesh.nInternalFaces();
-//
-//            forAll(pp, i)
-//            {
-//                if (!blockedFace[facei])
-//                {
-//                    label own = agglom[faceOwner[facei]];
-//
-//                    label globalNei = globalNeighbour[bFacei];
-//
-//                    if
-//                    (
-//                       !globalAgglom.isLocal(globalNei)
-//                     || globalAgglom.toLocal(globalNei) != own
-//                    )
-//                    {
-//                        m[offsets[own] + nFacesPerCell[own]++] = globalNei;
-//                    }
-//
-//                    ++facei;
-//                    ++bFacei;
-//                }
-//            }
-//        }
-//    }
-//
-//    // 3. Explicit connections between non-coupled boundary faces
-//    forAll(explicitConnections, i)
-//    {
-//        const labelPair& baffle = explicitConnections[i];
-//        label f0 = baffle.first();
-//        label f1 = baffle.second();
-//
-//        if (!blockedFace[f0] && blockedFace[f1])
-//        {
-//            label f0Own = agglom[faceOwner[f0]];
-//            label f1Own = agglom[faceOwner[f1]];
-//
-//            // Always count the connection between the two owner sides
-//            if (f0Own != f1Own)
-//            {
-//                m[offsets[f0Own] + nFacesPerCell[f0Own]++] =
-//                    globalAgglom.toGlobal(f1Own);
-//                m[offsets[f1Own] + nFacesPerCell[f1Own]++] =
-//                    globalAgglom.toGlobal(f0Own);
-//            }
-//
-//            // Add any neighbour side connections
-//            if (mesh.isInternalFace(f0))
-//            {
-//                label f0Nei = agglom[faceNeighbour[f0]];
-//
-//                if (mesh.isInternalFace(f1))
-//                {
-//                    // Internal faces
-//                    label f1Nei = agglom[faceNeighbour[f1]];
-//
-//                    if (f0Own != f1Nei)
-//                    {
-//                        m[offsets[f0Own] + nFacesPerCell[f0Own]++] =
-//                            globalAgglom.toGlobal(f1Nei);
-//                        m[offsets[f1Nei] + nFacesPerCell[f1Nei]++] =
-//                            globalAgglom.toGlobal(f1Nei);
-//                    }
-//                    if (f0Nei != f1Own)
-//                    {
-//                        m[offsets[f0Nei] + nFacesPerCell[f0Nei]++] =
-//                            globalAgglom.toGlobal(f1Own);
-//                        m[offsets[f1Own] + nFacesPerCell[f1Own]++] =
-//                            globalAgglom.toGlobal(f0Nei);
-//                    }
-//                    if (f0Nei != f1Nei)
-//                    {
-//                        m[offsets[f0Nei] + nFacesPerCell[f0Nei]++] =
-//                            globalAgglom.toGlobal(f1Nei);
-//                        m[offsets[f1Nei] + nFacesPerCell[f1Nei]++] =
-//                            globalAgglom.toGlobal(f0Nei);
-//                    }
-//                }
-//                else
-//                {
-//                    // f1 boundary face
-//                    if (f0Nei != f1Own)
-//                    {
-//                        m[offsets[f0Nei] + nFacesPerCell[f0Nei]++] =
-//                            globalAgglom.toGlobal(f1Own);
-//                        m[offsets[f1Own] + nFacesPerCell[f1Own]++] =
-//                            globalAgglom.toGlobal(f0Nei);
-//                    }
-//                }
-//            }
-//            else
-//            {
-//                if (mesh.isInternalFace(f1))
-//                {
-//                    label f1Nei = agglom[faceNeighbour[f1]];
-//                    if (f0Own != f1Nei)
-//                    {
-//                        m[offsets[f0Own] + nFacesPerCell[f0Own]++] =
-//                            globalAgglom.toGlobal(f1Nei);
-//                        m[offsets[f1Nei] + nFacesPerCell[f1Nei]++] =
-//                            globalAgglom.toGlobal(f0Own);
-//                    }
-//                }
-//            }
-//        }
-//    }
-//
-//
-//    // Check for duplicates connections between cells
-//    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-//    // Done as postprocessing step since we now have cellCells.
-//    label newIndex = 0;
-//    labelHashSet nbrCells;
-//
-//
-//    if (cellCells.size() == 0)
-//    {
-//        return;
-//    }
-//
-//    label startIndex = cellCells.offsets()[0];
-//
-//    forAll(cellCells, celli)
-//    {
-//        nbrCells.clear();
-//        nbrCells.insert(globalAgglom.toGlobal(celli));
-//
-//        label endIndex = cellCells.offsets()[celli+1];
-//
-//        for (label i = startIndex; i < endIndex; ++i)
-//        {
-//            if (nbrCells.insert(cellCells.m()[i]))
-//            {
-//                cellCells.m()[newIndex++] = cellCells.m()[i];
-//            }
-//        }
-//        startIndex = endIndex;
-//        cellCells.offsets()[celli+1] = newIndex;
-//    }
-//
-//    cellCells.m().setSize(newIndex);
-//
-//    //forAll(cellCells, celli)
-//    //{
-//    //    Pout<< "Original: Coarse cell " << celli << endl;
-//    //    forAll(mesh.cellCells()[celli], i)
-//    //    {
-//    //        Pout<< "    nbr:" << mesh.cellCells()[celli][i] << endl;
-//    //    }
-//    //    Pout<< "Compacted: Coarse cell " << celli << endl;
-//    //    const labelUList cCells = cellCells[celli];
-//    //    forAll(cCells, i)
-//    //    {
-//    //        Pout<< "    nbr:" << cCells[i] << endl;
-//    //    }
-//    //}
-//}
-
+// NOTE:
+// - alternative calcCellCells that handled explicitConnections was
+//   deactivated (2014 or earlier) and finally removed APR-2018.
 
 Foam::labelList Foam::decompositionMethod::decompose
 (