From 42de624344b8e78833470f037b39e3bd9a754fcc Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Tue, 26 Apr 2022 23:10:05 +0200
Subject: [PATCH] ENH: consolidate processorTopology handling for volume and
 area meshes

- relocate templating to factory method 'New'.
  Adds provisions for more general re-use.

- expose processor topology in globalMesh as topology()

- wrap proc->patch lookup as processorTopology::procPatchLookup method
  (failsafe). May consider using Map<label> for its storage in the
  future.
---
 .../Test-processorTopology.C                  |   8 +-
 .../extrude/extrudeMesh/extrudeMesh.C         |   1 +
 .../createBaffles/createBaffles.C             |   1 +
 .../lduAddressing/lduSchedule/lduSchedule.H   |  35 ++-
 .../ProcessorTopology/ProcessorTopology.C     | 273 ------------------
 .../ProcessorTopology/ProcessorTopology.H     | 126 --------
 .../lduMesh/lduPrimitiveMeshTemplates.C       |  38 +--
 .../polyMesh/globalMeshData/globalMeshData.C  |  40 ++-
 .../polyMesh/globalMeshData/globalMeshData.H  |  26 +-
 .../globalMeshData/processorTopology.H        |  51 ----
 .../parallel/commSchedule/commSchedule.C      |   3 +-
 .../parallel/commSchedule/commSchedule.H      |  12 +-
 .../processorTopology/processorTopology.H     | 176 +++++++++++
 .../processorTopology/processorTopologyNew.H  | 229 +++++++++++++++
 .../freeSurfacePointDisplacement.C            |   1 +
 .../interfaceTrackingFvMesh.C                 |   1 +
 .../polyTopoChange/addPatchCellLayer.C        |  42 +--
 .../faGlobalMeshData/faGlobalMeshData.C       |  21 +-
 .../faGlobalMeshData/faGlobalMeshData.H       | 102 ++++---
 .../faGlobalMeshData/faProcessorTopology.H    |  60 ----
 .../constraint/processor/processorFaPatch.C   |   1 +
 .../fvMesh/fvMeshSubset/fvMeshSubset.C        |   1 +
 .../field/fieldExtents/fieldExtents.C         |   1 +
 .../utilities/vtkWrite/vtkWriteUpdate.C       |   1 +
 .../surfaceAlignedSBRStressFvMotionSolver.C   |   1 +
 src/lagrangian/basic/Cloud/Cloud.C            |   3 +-
 .../trackingInverseDistance/voxelMeshSearch.C |   2 +-
 src/sampling/meshToMesh/meshToMesh.C          |   1 +
 .../sampledFaceZone/sampledFaceZone.C         |   1 +
 29 files changed, 618 insertions(+), 640 deletions(-)
 delete mode 100644 src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.C
 delete mode 100644 src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.H
 delete mode 100644 src/OpenFOAM/meshes/polyMesh/globalMeshData/processorTopology.H
 create mode 100644 src/OpenFOAM/parallel/processorTopology/processorTopology.H
 create mode 100644 src/OpenFOAM/parallel/processorTopology/processorTopologyNew.H
 delete mode 100644 src/finiteArea/faMesh/faGlobalMeshData/faProcessorTopology.H

diff --git a/applications/test/processorTopology/Test-processorTopology.C b/applications/test/processorTopology/Test-processorTopology.C
index 1d8d7fab1a..c4e87c8868 100644
--- a/applications/test/processorTopology/Test-processorTopology.C
+++ b/applications/test/processorTopology/Test-processorTopology.C
@@ -44,7 +44,7 @@ int main(int argc, char *argv[])
     argList::noFunctionObjects();
     argList::addNote
     (
-        "Create a metis graph file representation for an OpenFOAM mesh"
+        "Create graph of OpenFOAM mesh connections"
     );
 
     #include "setRootCase.H"
@@ -59,9 +59,9 @@ int main(int argc, char *argv[])
     #include "createTime.H"
     #include "createPolyMesh.H"
 
-    const globalMeshData& globData = mesh.globalData();
-
-    const labelListList& connectivity = globData;
+    // Adjacency table
+    const labelListList& connectivity =
+        mesh.globalData().topology().procNeighbours();
 
     if (Pstream::master())
     {
diff --git a/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C b/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
index 680eb5815e..bc5fba6e60 100644
--- a/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
+++ b/applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMesh.C
@@ -60,6 +60,7 @@ Description
 #include "wedgePolyPatch.H"
 #include "planeExtrusion.H"
 #include "emptyPolyPatch.H"
+#include "processorPolyPatch.H"
 #include "processorMeshes.H"
 #include "hexRef8Data.H"
 
diff --git a/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C b/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
index 269317bc3b..ca13af55b9 100644
--- a/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
+++ b/applications/utilities/mesh/manipulation/createBaffles/createBaffles.C
@@ -57,6 +57,7 @@ Description
 
 #include "fvMeshTools.H"
 #include "topoSet.H"
+#include "processorPolyPatch.H"
 #include "processorMeshes.H"
 
 using namespace Foam;
diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduSchedule/lduSchedule.H b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduSchedule/lduSchedule.H
index 945b1bde37..8af52779e3 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduSchedule/lduSchedule.H
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduSchedule/lduSchedule.H
@@ -32,8 +32,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef lduSchedule_H
-#define lduSchedule_H
+#ifndef Foam_lduSchedule_H
+#define Foam_lduSchedule_H
 
 #include "List.H"
 
@@ -42,14 +42,17 @@ Description
 namespace Foam
 {
 
-// Forward declaration of friend functions and operators
+// Forward Declarations
 
 struct lduScheduleEntry;
 Ostream& operator<<(Ostream& os, const lduScheduleEntry& lb);
 
+//- A List of lduSchedule entries.
+typedef List<lduScheduleEntry> lduSchedule;
+
 
 /*---------------------------------------------------------------------------*\
-                      Class lduSchedule Declaration
+                      Class lduScheduleEntry Declaration
 \*---------------------------------------------------------------------------*/
 
 struct lduScheduleEntry
@@ -57,11 +60,22 @@ struct lduScheduleEntry
     label patch;
     bool init;
 
-    friend bool operator!=
-    (
-        const lduScheduleEntry& lb1,
-        const lduScheduleEntry& lb2
-    )
+    //- Define patch for initEvaluate()
+    void setInitEvaluate(const label patchi) noexcept
+    {
+        patch = patchi;
+        init = true;
+    }
+
+    //- Define patch for evaluate()
+    void setEvaluate(const label patchi) noexcept
+    {
+        patch = patchi;
+        init = false;
+    }
+
+    //- Always unequal: each entry is supposed to be unique!
+    friend bool operator!=(const lduScheduleEntry&, const lduScheduleEntry&)
     {
         return true;
     }
@@ -74,9 +88,6 @@ struct lduScheduleEntry
 };
 
 
-typedef List<lduScheduleEntry> lduSchedule;
-
-
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 } // End namespace Foam
diff --git a/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.C b/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.C
deleted file mode 100644
index 359f7ae0b9..0000000000
--- a/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.C
+++ /dev/null
@@ -1,273 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2022 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 "ProcessorTopology.H"
-#include "ListOps.H"
-#include "Pstream.H"
-#include "commSchedule.H"
-
-// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
-
-template<class Container, class ProcPatch>
-Foam::labelList Foam::ProcessorTopology<Container, ProcPatch>::procNeighbours
-(
-    const label nProcs,
-    const Container& patches
-)
-{
-    // Determine number of processor neighbours and max neighbour id.
-
-    label nNeighbours = 0;
-
-    label maxNb = 0;
-
-    boolList isNeighbourProc(nProcs, false);
-
-    forAll(patches, patchi)
-    {
-        const auto* cpp = isA<ProcPatch>(patches[patchi]);
-        if (cpp)
-        {
-            const label nbrProci = cpp->neighbProcNo();
-
-            if (!isNeighbourProc[nbrProci])
-            {
-                isNeighbourProc[nbrProci] = true;
-                maxNb = max(maxNb, nbrProci);
-                ++nNeighbours;
-            }
-        }
-    }
-
-    labelList neighbours(nNeighbours, -1);
-
-    nNeighbours = 0;
-
-    forAll(isNeighbourProc, proci)
-    {
-        if (isNeighbourProc[proci])
-        {
-            neighbours[nNeighbours++] = proci;
-        }
-    }
-
-    procPatchMap_.setSize(maxNb + 1);
-    procPatchMap_ = -1;
-
-    forAll(patches, patchi)
-    {
-        const auto* cpp = isA<ProcPatch>(patches[patchi]);
-        if (cpp)
-        {
-            const label nbrProci = cpp->neighbProcNo();
-
-            // Reverse map
-            procPatchMap_[nbrProci] = patchi;
-        }
-    }
-
-    return neighbours;
-}
-
-
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
-
-template<class Container, class ProcPatch>
-Foam::ProcessorTopology<Container, ProcPatch>::ProcessorTopology
-(
-    const Container& patches,
-    const label comm
-)
-:
-    labelListList(Pstream::nProcs(comm)),
-    patchSchedule_()
-{
-    if (Pstream::parRun())
-    {
-        // Fill my 'slot' with my neighbours
-        operator[](Pstream::myProcNo(comm)) =
-            procNeighbours(this->size(), patches);
-
-        // Distribute to all processors
-        Pstream::allGatherList(*this, Pstream::msgType(), comm);
-    }
-
-    if
-    (
-        Pstream::parRun()
-     && Pstream::defaultCommsType == Pstream::commsTypes::scheduled
-    )
-    {
-        patchSchedule_.resize(2*patches.size());
-
-        label patchEvali = 0;
-
-        // 1. All non-processor patches
-        // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-        forAll(patches, patchi)
-        {
-            if (!isA<ProcPatch>(patches[patchi]))
-            {
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = true;
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = false;
-            }
-        }
-
-        // 2. All processor patches
-        // ~~~~~~~~~~~~~~~~~~~~~~~~
-
-        // Determine the schedule for all. Insert processor pair once
-        // to determine the schedule. Each processor pair stands for both
-        // send and receive.
-        label nComms = 0;
-        for (const labelList& neighbours : *this)
-        {
-            nComms += neighbours.size();
-        }
-        DynamicList<labelPair> comms(nComms);
-
-        forAll(*this, proci)
-        {
-            const labelList& neighbours = operator[](proci);
-
-            for (const label nbrProci : neighbours)
-            {
-                if (proci < nbrProci)
-                {
-                    comms.append(labelPair(proci, nbrProci));
-                }
-            }
-        }
-        comms.shrink();
-
-        // Determine a schedule.
-        labelList mySchedule
-        (
-            commSchedule
-            (
-                Pstream::nProcs(comm),
-                comms
-            ).procSchedule()[Pstream::myProcNo(comm)]
-        );
-
-        for (const label commI : mySchedule)
-        {
-            // Get the other processor
-            label nb = comms[commI][0];
-            if (nb == Pstream::myProcNo(comm))
-            {
-                nb = comms[commI][1];
-            }
-            label patchi = procPatchMap_[nb];
-
-            if (Pstream::myProcNo(comm) > nb)
-            {
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = true;
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = false;
-            }
-            else
-            {
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = false;
-                patchSchedule_[patchEvali].patch = patchi;
-                patchSchedule_[patchEvali++].init = true;
-            }
-        }
-    }
-    else
-    {
-        patchSchedule_ = nonBlockingSchedule(patches);
-    }
-}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-template<class Container, class ProcPatch>
-Foam::lduSchedule
-Foam::ProcessorTopology<Container, ProcPatch>::nonBlockingSchedule
-(
-    const Container& patches
-)
-{
-    lduSchedule patchSchedule(2*patches.size());
-
-    label patchEvali = 0;
-
-    // 1. All non-processor patches
-    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-    // Have evaluate directly after initEvaluate. Could have them separated
-    // as long as they're not intermingled with processor patches since
-    // then e.g. any reduce parallel traffic would interfere with the
-    // processor swaps.
-
-    forAll(patches, patchi)
-    {
-        if (!isA<ProcPatch>(patches[patchi]))
-        {
-            patchSchedule[patchEvali].patch = patchi;
-            patchSchedule[patchEvali++].init = true;
-            patchSchedule[patchEvali].patch = patchi;
-            patchSchedule[patchEvali++].init = false;
-        }
-    }
-
-    // 2. All processor patches
-    // ~~~~~~~~~~~~~~~~~~~~~~~~
-
-    // 2a. initEvaluate
-    forAll(patches, patchi)
-    {
-        if (isA<ProcPatch>(patches[patchi]))
-        {
-            patchSchedule[patchEvali].patch = patchi;
-            patchSchedule[patchEvali++].init = true;
-        }
-    }
-
-    // 2b. evaluate
-    forAll(patches, patchi)
-    {
-        if (isA<ProcPatch>(patches[patchi]))
-        {
-            patchSchedule[patchEvali].patch = patchi;
-            patchSchedule[patchEvali++].init = false;
-        }
-    }
-
-    return patchSchedule;
-}
-
-
-// ************************************************************************* //
diff --git a/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.H b/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.H
deleted file mode 100644
index 3dbcff1777..0000000000
--- a/src/OpenFOAM/meshes/ProcessorTopology/ProcessorTopology.H
+++ /dev/null
@@ -1,126 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2011-2016 OpenFOAM Foundation
--------------------------------------------------------------------------------
-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/>.
-
-Class
-    Foam::ProcessorTopology
-
-Description
-    Determines processor-processor connection. After instantiation contains
-    on all processors the processor-processor connection table.
-
-    *this[proci] gives the list of neighbouring processors.
-
-    TODO: This does not currently correctly support multiple processor
-    patches connecting two processors.
-
-SourceFiles
-    ProcessorTopology.C
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_ProcessorTopology_H
-#define Foam_ProcessorTopology_H
-
-#include "labelList.H"
-#include "lduSchedule.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-/*---------------------------------------------------------------------------*\
-                       Class ProcessorTopology Declaration
-\*---------------------------------------------------------------------------*/
-
-template<class Container, class ProcPatch>
-class ProcessorTopology
-:
-    public labelListList
-{
-    // Private Data
-
-        //- Local map from neighbour proc to patchi. Different per processor!
-        //  -1 or patchi for connection to procID
-        labelList procPatchMap_;
-
-        //- Order in which the patches should be initialised/evaluated
-        //  corresponding to the schedule
-        lduSchedule patchSchedule_;
-
-
-    // Private Member Functions
-
-        //- Return all neighbouring processors of this processor.
-        //  Sets procPatchMap_.
-        labelList procNeighbours(const label nProcs, const Container&);
-
-public:
-
-    // Constructors
-
-        //- Construct from boundaryMesh
-        ProcessorTopology(const Container& patches, const label comm);
-
-
-    // Static Functions
-
-        //- Calculate non-blocking (i.e. unscheduled) schedule
-        static lduSchedule nonBlockingSchedule(const Container& patches);
-
-
-    // Member Functions
-
-        //- From neighbour processor to index in boundaryMesh.
-        //  Local information (so not same over all processors)
-        const labelList& procPatchMap() const noexcept
-        {
-            return procPatchMap_;
-        }
-
-        //- Order in which the patches should be initialised/evaluated
-        //- corresponding to the schedule
-        const lduSchedule& patchSchedule() const noexcept
-        {
-            return patchSchedule_;
-        }
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#ifdef NoRepository
-    #include "ProcessorTopology.C"
-#endif
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //
diff --git a/src/OpenFOAM/meshes/lduMesh/lduPrimitiveMeshTemplates.C b/src/OpenFOAM/meshes/lduMesh/lduPrimitiveMeshTemplates.C
index ed5929d74a..6b774f304f 100644
--- a/src/OpenFOAM/meshes/lduMesh/lduPrimitiveMeshTemplates.C
+++ b/src/OpenFOAM/meshes/lduMesh/lduPrimitiveMeshTemplates.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013 OpenFOAM Foundation
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -36,38 +37,37 @@ Foam::lduSchedule Foam::lduPrimitiveMesh::nonBlockingSchedule
 )
 {
     lduSchedule schedule(2*interfaces.size());
-    label slotI = 0;
 
-    forAll(interfaces, i)
+    // 1. All non-processor patches
+    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    label patchEvali = 0;
+
+    forAll(interfaces, patchi)
     {
-        if (interfaces.set(i) && !isA<ProcPatch>(interfaces[i]))
+        if (interfaces.set(patchi) && !isA<ProcPatch>(interfaces[patchi]))
         {
-            schedule[slotI].patch = i;
-            schedule[slotI].init = true;
-            slotI++;
-            schedule[slotI].patch = i;
-            schedule[slotI].init = false;
-            slotI++;
+            schedule[patchEvali++].setInitEvaluate(patchi);
+            schedule[patchEvali++].setEvaluate(patchi);
         }
     }
 
-    forAll(interfaces, i)
+    // 2. All processor patches
+    // ~~~~~~~~~~~~~~~~~~~~~~~~
+
+    forAll(interfaces, patchi)
     {
-        if (interfaces.set(i) && isA<ProcPatch>(interfaces[i]))
+        if (interfaces.set(patchi) && isA<ProcPatch>(interfaces[patchi]))
         {
-            schedule[slotI].patch = i;
-            schedule[slotI].init = true;
-            slotI++;
+            schedule[patchEvali++].setInitEvaluate(patchi);
         }
     }
 
-    forAll(interfaces, i)
+    forAll(interfaces, patchi)
     {
-        if (interfaces.set(i) && isA<ProcPatch>(interfaces[i]))
+        if (interfaces.set(patchi) && isA<ProcPatch>(interfaces[patchi]))
         {
-            schedule[slotI].patch = i;
-            schedule[slotI].init = false;
-            slotI++;
+            schedule[patchEvali++].setEvaluate(patchi);
         }
     }
 
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
index 0741da6531..8627307f8d 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
@@ -27,14 +27,15 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "globalMeshData.H"
-#include "Pstream.H"
-#include "processorPolyPatch.H"
 #include "globalPoints.H"
 #include "polyMesh.H"
 #include "mapDistribute.H"
 #include "labelIOList.H"
 #include "mergePoints.H"
+#include "processorPolyPatch.H"
+#include "processorTopologyNew.H"
 #include "globalIndexAndTransform.H"
+#include "Pstream.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -61,15 +62,15 @@ public:
 
 void Foam::globalMeshData::initProcAddr()
 {
-    processorPatchIndices_.setSize(mesh_.boundaryMesh().size());
+    processorPatchIndices_.resize_nocopy(mesh_.boundaryMesh().size());
     processorPatchIndices_ = -1;
 
-    processorPatchNeighbours_.setSize(mesh_.boundaryMesh().size());
+    processorPatchNeighbours_.resize_nocopy(mesh_.boundaryMesh().size());
     processorPatchNeighbours_ = -1;
 
     // Construct processor patch indexing. processorPatchNeighbours_ only
     // set if running in parallel!
-    processorPatches_.setSize(mesh_.boundaryMesh().size());
+    processorPatches_.resize_nocopy(mesh_.boundaryMesh().size());
 
     label nNeighbours = 0;
 
@@ -81,7 +82,7 @@ void Foam::globalMeshData::initProcAddr()
             processorPatchIndices_[patchi] = nNeighbours++;
         }
     }
-    processorPatches_.setSize(nNeighbours);
+    processorPatches_.resize(nNeighbours);
 
 
     if (Pstream::parRun())
@@ -1728,14 +1729,21 @@ void Foam::globalMeshData::calcGlobalCoPointSlaves() const
 
 Foam::globalMeshData::globalMeshData(const polyMesh& mesh)
 :
-    processorTopology(mesh.boundaryMesh(), UPstream::worldComm),
     mesh_(mesh),
     nTotalPoints_(-1),
     nTotalFaces_(-1),
     nTotalCells_(-1),
-    processorPatches_(0),
-    processorPatchIndices_(0),
-    processorPatchNeighbours_(0),
+    processorTopology_
+    (
+        processorTopology::New<processorPolyPatch>
+        (
+            mesh.boundaryMesh(),
+            UPstream::worldComm
+        )
+    ),
+    processorPatches_(),
+    processorPatchIndices_(),
+    processorPatchNeighbours_(),
     nGlobalPoints_(-1),
     sharedPointLabelsPtr_(nullptr),
     sharedPointAddrPtr_(nullptr),
@@ -1750,10 +1758,9 @@ Foam::globalMeshData::globalMeshData(const polyMesh& mesh)
 
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
+// A non-default destructor since we had incomplete types in the header
 Foam::globalMeshData::~globalMeshData()
-{
-    clearOut();
-}
+{}
 
 
 void Foam::globalMeshData::clearOut()
@@ -1780,6 +1787,7 @@ void Foam::globalMeshData::clearOut()
     globalPointSlavesPtr_.clear();
     globalPointTransformedSlavesPtr_.clear();
     globalPointSlavesMapPtr_.clear();
+
     // Edge
     globalEdgeNumberingPtr_.clear();
     globalEdgeSlavesPtr_.clear();
@@ -2728,7 +2736,7 @@ void Foam::globalMeshData::updateMesh()
 
     if (debug)
     {
-        Pout<< "globalMeshData : nTotalFaces_:" << nTotalFaces_ << endl;
+        Pout<< "globalMeshData : nTotalFaces:" << nTotalFaces_ << endl;
     }
 
     nTotalCells_ = returnReduce
@@ -2741,7 +2749,7 @@ void Foam::globalMeshData::updateMesh()
 
     if (debug)
     {
-        Pout<< "globalMeshData : nTotalCells_:" << nTotalCells_ << endl;
+        Pout<< "globalMeshData : nTotalCells:" << nTotalCells_ << endl;
     }
 
     nTotalPoints_ = returnReduce
@@ -2757,7 +2765,7 @@ void Foam::globalMeshData::updateMesh()
 
     if (debug)
     {
-        Pout<< "globalMeshData : nTotalPoints_:" << nTotalPoints_ << endl;
+        Pout<< "globalMeshData : nTotalPoints:" << nTotalPoints_ << endl;
     }
 }
 
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.H b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.H
index 41ed3e36fb..fb75f9677e 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.H
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -81,8 +81,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef globalMeshData_H
-#define globalMeshData_H
+#ifndef Foam_globalMeshData_H
+#define Foam_globalMeshData_H
 
 #include "processorTopology.H"
 #include "labelPair.H"
@@ -106,8 +106,6 @@ class bitSet;
 \*---------------------------------------------------------------------------*/
 
 class globalMeshData
-:
-    public processorTopology
 {
     // Private Data
 
@@ -129,6 +127,9 @@ class globalMeshData
 
         // Processor patch addressing (be careful if not running in parallel!)
 
+            //- The processor/processor topology
+            processorTopology processorTopology_;
+
             //- List of processor patch labels
             //  (size of list = number of processor patches)
             labelList processorPatches_;
@@ -377,6 +378,19 @@ public:
 
         // Processor patch addressing (be careful when not running in parallel)
 
+            //- The processor to processor topology.
+            const processorTopology& topology() const noexcept
+            {
+                return processorTopology_;
+            }
+
+            //- Order in which the patches should be initialised/evaluated
+            //- corresponding to the schedule
+            const lduSchedule& patchSchedule() const noexcept
+            {
+                return processorTopology_.patchSchedule();
+            }
+
             //- Return list of processor patch labels
             //  (size of list = number of processor patches)
             const labelList& processorPatches() const noexcept
@@ -393,7 +407,7 @@ public:
             }
 
             //- Return processorPatchIndices of the neighbours
-            //  processor patches. -1 if not running parallel.
+            //- processor patches. -1 if not running parallel.
             const labelList& processorPatchNeighbours() const noexcept
             {
                 return processorPatchNeighbours_;
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/processorTopology.H b/src/OpenFOAM/meshes/polyMesh/globalMeshData/processorTopology.H
deleted file mode 100644
index 950f2d1e4f..0000000000
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/processorTopology.H
+++ /dev/null
@@ -1,51 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2011-2013 OpenFOAM Foundation
--------------------------------------------------------------------------------
-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/>.
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef processorTopology_H
-#define processorTopology_H
-
-#include "ProcessorTopology.H"
-#include "processorPolyPatch.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-typedef ProcessorTopology<polyPatchList, processorPolyPatch> processorTopology;
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //
diff --git a/src/OpenFOAM/parallel/commSchedule/commSchedule.C b/src/OpenFOAM/parallel/commSchedule/commSchedule.C
index 6bb6d5949b..32302b39fb 100644
--- a/src/OpenFOAM/parallel/commSchedule/commSchedule.C
+++ b/src/OpenFOAM/parallel/commSchedule/commSchedule.C
@@ -90,7 +90,8 @@ Foam::commSchedule::commSchedule
         if (proc0 < 0 || proc0 >= nProcs || proc1 < 0 || proc1 >= nProcs)
         {
             FatalErrorInFunction
-                << "Illegal processor " << comms[commI] << abort(FatalError);
+                << "Illegal processor(s): "
+                << comms[commI] << abort(FatalError);
         }
 
         procToComms[proc0].append(commI);
diff --git a/src/OpenFOAM/parallel/commSchedule/commSchedule.H b/src/OpenFOAM/parallel/commSchedule/commSchedule.H
index 765f4165ff..821dfa9afc 100644
--- a/src/OpenFOAM/parallel/commSchedule/commSchedule.H
+++ b/src/OpenFOAM/parallel/commSchedule/commSchedule.H
@@ -42,8 +42,8 @@ Description
       - procSchedule()[proci] gives per proci
 
     Does not care whether 'talking' is first send, second receive or maybe
-    full swap. This is all responsibility of caller. See ProcessorTopology
-    class for use in scheduling processor boundary swaps.
+    full swap. This is all responsibility of caller.
+    See Foam::rocessorTopology for use in scheduling processor boundary swaps.
 
 SourceFiles
     commSchedule.C
@@ -78,13 +78,17 @@ class commSchedule
 
 public:
 
+    //- Runtime type information
     ClassName("commSchedule");
 
+
     // Constructors
 
         //- Construct from wanted communication. Wanted communication is between
-        //  two processors. Can be a one-way communication or
-        //  two-way communication, that is up to the caller. This class just
+        //- two processors. Can be a one-way communication or
+        //- two-way communication, that is up to the caller.
+        //
+        //  This class just
         //  determines an order for it such that any processor is only talking
         //  to one other at a time. After construction:
         //  - schedule is the order in which comms is done.
diff --git a/src/OpenFOAM/parallel/processorTopology/processorTopology.H b/src/OpenFOAM/parallel/processorTopology/processorTopology.H
new file mode 100644
index 0000000000..3cce0ec109
--- /dev/null
+++ b/src/OpenFOAM/parallel/processorTopology/processorTopology.H
@@ -0,0 +1,176 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2022 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/>.
+
+Class
+    Foam::processorTopology
+
+Description
+    Determines/represents processor-processor connection.
+    After instantiation contains the processor-processor connection table
+    (globally synchronized on all processors).
+
+Note
+    A processorTopology is usually generated by using the \c New
+    factory method, which has been wrapped into a separate header to
+    minimize dependencies.
+
+Warning
+    Does not currently correctly support multiple processor
+    patches connecting two processors.
+
+SourceFiles
+    processorTopologyNew.H
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_processorTopology_H
+#define Foam_processorTopology_H
+
+#include "labelList.H"
+#include "lduSchedule.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+                      Class processorTopology Declaration
+\*---------------------------------------------------------------------------*/
+
+class processorTopology
+{
+    // Private Data
+
+        //- The processor to processor connection (adjacency) table
+        labelListList procNeighbours_;
+
+        //- Order in which the patches should be initialised/evaluated
+        //- corresponding to the schedule
+        lduSchedule patchSchedule_;
+
+        //- Local map from neighbour proc to patchi. Different per processor!
+        //  -1 or patchi for connection to procID
+        labelList procPatchMap_;
+
+
+    // Private Member Functions
+
+        //- From neighbour processor to index in our local boundary.
+        //  Local information (so not same over all processors)
+        ///const labelList& procPatchMap() const noexcept
+        ///{
+        ///    return procPatchMap_;
+        ///}
+
+        //- Which \em local boundary is attached to specified processor
+        //  Local information (so not same over all processors)
+        //  \return -1 if not currently connected to specified processor.
+        label procToLocalPatch(const label proci) const
+        {
+            return
+            (
+                proci >= 0 && proci < procPatchMap_.size()
+              ? procPatchMap_[proci]
+              : static_cast<label>(-1)
+            );
+        }
+
+
+public:
+
+    // Generated Methods
+
+        //- Default construct (empty)
+        processorTopology() = default;
+
+        //- Copy construct
+        processorTopology(const processorTopology&) = default;
+
+        //- Move construct
+        processorTopology(processorTopology&&) = default;
+
+        //- Copy assignment
+        processorTopology& operator=(const processorTopology&) = default;
+
+        //- Move assignment
+        processorTopology& operator=(processorTopology&&) = default;
+
+
+    // Static Functions
+
+        //- Factory method to create topology, schedule and proc/patch maps.
+        //  Scans the list of patches for processor connections corresponding
+        //  to the ProcPatch type.
+        template<class ProcPatch, class PatchListType>
+        static processorTopology New
+        (
+            const PatchListType& patches,
+            const label comm
+        );
+
+
+    // Member Functions
+
+        //- The number of processors used by the topology
+        label nProcs() const noexcept
+        {
+            return procNeighbours_.size();
+        }
+
+        //- The processor to processor connection topology
+        //- (like an adjacency list). Globally synchronized information
+        const labelListList& procNeighbours() const noexcept
+        {
+            return procNeighbours_;
+        }
+
+        //- Order in which the patches should be initialised/evaluated
+        //- corresponding to the schedule
+        const lduSchedule& patchSchedule() const noexcept
+        {
+            return patchSchedule_;
+        }
+
+        //- Which \em local boundary is attached to specified processor
+        //  Local information (so not same over all processors)
+        //  \return -1 if not currently connected to specified processor.
+        label procPatchLookup(const label proci) const
+        {
+            return procToLocalPatch(proci);
+        }
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/OpenFOAM/parallel/processorTopology/processorTopologyNew.H b/src/OpenFOAM/parallel/processorTopology/processorTopologyNew.H
new file mode 100644
index 0000000000..e7f966143a
--- /dev/null
+++ b/src/OpenFOAM/parallel/processorTopology/processorTopologyNew.H
@@ -0,0 +1,229 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2011-2017 OpenFOAM Foundation
+    Copyright (C) 2022 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/>.
+
+InClass
+    Foam::processorTopology
+
+Description
+    Define the processor-processor connection table by walking a list of
+    patches and detecting the processor ones.
+
+    This has been split off as a separate include from processorTopology
+    to minimize dependencies.
+
+Warning
+    Does not currently correctly support multiple processor
+    patches connecting two processors.
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_processorTopologyNew_H
+#define Foam_processorTopologyNew_H
+
+#include "processorTopology.H"
+#include "bitSet.H"
+#include "commSchedule.H"
+#include "DynamicList.H"
+#include "Pstream.H"
+
+// * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
+
+template<class ProcPatch, class PatchListType>
+Foam::processorTopology Foam::processorTopology::New
+(
+    const PatchListType& patches,
+    const label comm
+)
+{
+    const label myProci = Pstream::myProcNo(comm);
+    const label nProcs = Pstream::nProcs(comm);
+
+    processorTopology procTopo;
+
+    auto& procToProcs = procTopo.procNeighbours_;
+    auto& procToPatch = procTopo.procPatchMap_;
+    auto& schedule = procTopo.patchSchedule_;
+
+    procToProcs.resize(nProcs);
+    schedule.resize(2*patches.size());
+
+
+    if (Pstream::parRun())
+    {
+        // Fill my 'slot' with my neighbours
+        auto& procSlot = procToProcs[myProci];
+
+        bitSet isNeighbour(procToProcs.size());
+
+        forAll(patches, patchi)
+        {
+            const auto* cpp = isA<ProcPatch>(patches[patchi]);
+            if (cpp)
+            {
+                const label nbrProci = cpp->neighbProcNo();
+
+                isNeighbour.set(nbrProci);
+            }
+        }
+
+        // The neighbouring procs in sorted (ascending) order
+        procSlot = isNeighbour.sortedToc();
+
+        const label maxNbrProci = procSlot.empty() ? -1 : procSlot.last();
+
+        // Note could also use Map<label> if desired
+        procToPatch.resize_nocopy(maxNbrProci + 1);
+        procToPatch = -1;
+
+        forAll(patches, patchi)
+        {
+            const auto* cpp = isA<ProcPatch>(patches[patchi]);
+            if (cpp)
+            {
+                const label nbrProci = cpp->neighbProcNo();
+
+                // Reverse map
+                procToPatch[nbrProci] = patchi;
+            }
+        }
+
+        // Synchronize on all processors
+        Pstream::allGatherList(procToProcs, UPstream::msgType(), comm);
+    }
+
+
+    // Define the schedule
+
+    label patchEvali = 0;
+
+    // 1. All non-processor patches
+    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    forAll(patches, patchi)
+    {
+        if (!isA<ProcPatch>(patches[patchi]))
+        {
+            schedule[patchEvali++].setInitEvaluate(patchi);
+            schedule[patchEvali++].setEvaluate(patchi);
+        }
+    }
+
+
+    // 2. All processor patches
+    // ~~~~~~~~~~~~~~~~~~~~~~~~
+
+    if
+    (
+        Pstream::parRun()
+     && Pstream::defaultCommsType == Pstream::commsTypes::scheduled
+    )
+    {
+        // Determine the schedule for all processor patches.
+        // Insert processor pair once to determine the schedule.
+        // Each processor pair stands for both send and receive.
+
+        label nComms = 0;
+        for (const labelList& nbrProcs : procToProcs)
+        {
+            nComms += nbrProcs.size();
+        }
+        DynamicList<labelPair> comms(nComms/2);
+
+        forAll(procToProcs, proci)
+        {
+            for (const label nbrProci : procToProcs[proci])
+            {
+                if (proci < nbrProci)
+                {
+                    comms.append(labelPair(proci, nbrProci));
+                }
+            }
+        }
+
+        // Determine a schedule.
+        labelList mySchedule
+        (
+            commSchedule
+            (
+                nProcs,
+                comms
+            ).procSchedule()[myProci]
+        );
+
+        for (const label scheduleIndex : mySchedule)
+        {
+            // Get the other processor
+            label nbrProci = comms[scheduleIndex][0];
+            if (nbrProci == myProci)
+            {
+                nbrProci = comms[scheduleIndex][1];
+            }
+            const label patchi = procToPatch[nbrProci];
+
+            if (myProci > nbrProci)
+            {
+                schedule[patchEvali++].setInitEvaluate(patchi);
+                schedule[patchEvali++].setEvaluate(patchi);
+            }
+            else
+            {
+                schedule[patchEvali++].setEvaluate(patchi);
+                schedule[patchEvali++].setInitEvaluate(patchi);
+            }
+        }
+    }
+    else
+    {
+        // Non-blocking schedule for processor patches
+
+        // initEvaluate
+        forAll(patches, patchi)
+        {
+            if (isA<ProcPatch>(patches[patchi]))
+            {
+                schedule[patchEvali++].setInitEvaluate(patchi);
+            }
+        }
+
+        // evaluate
+        forAll(patches, patchi)
+        {
+            if (isA<ProcPatch>(patches[patchi]))
+            {
+                schedule[patchEvali++].setEvaluate(patchi);
+            }
+        }
+    }
+
+    return procTopo;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/dynamicFaMesh/interfaceTrackingFvMesh/freeSurfacePointDisplacement.C b/src/dynamicFaMesh/interfaceTrackingFvMesh/freeSurfacePointDisplacement.C
index 46e1deffda..d8d92e959c 100644
--- a/src/dynamicFaMesh/interfaceTrackingFvMesh/freeSurfacePointDisplacement.C
+++ b/src/dynamicFaMesh/interfaceTrackingFvMesh/freeSurfacePointDisplacement.C
@@ -28,6 +28,7 @@ License
 #include "interfaceTrackingFvMesh.H"
 #include "primitivePatchInterpolation.H"
 #include "emptyFaPatch.H"
+#include "processorFaPatch.H"
 #include "wedgeFaPatch.H"
 #include "wallFvPatch.H"
 #include "coordinateSystem.H"
diff --git a/src/dynamicFaMesh/interfaceTrackingFvMesh/interfaceTrackingFvMesh.C b/src/dynamicFaMesh/interfaceTrackingFvMesh/interfaceTrackingFvMesh.C
index 94c4e8c285..8642f515db 100644
--- a/src/dynamicFaMesh/interfaceTrackingFvMesh/interfaceTrackingFvMesh.C
+++ b/src/dynamicFaMesh/interfaceTrackingFvMesh/interfaceTrackingFvMesh.C
@@ -30,6 +30,7 @@ License
 #include "addToRunTimeSelectionTable.H"
 #include "motionSolver.H"
 #include "volFields.H"
+#include "processorFaPatch.H"
 #include "wedgeFaPatch.H"
 #include "wedgeFaPatchFields.H"
 #include "slipFaPatchFields.H"
diff --git a/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C b/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
index b0efd6df4b..fa1d8b90dc 100644
--- a/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
+++ b/src/dynamicMesh/polyTopoChange/polyTopoChange/addPatchCellLayer.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2017,2020-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -1201,30 +1201,30 @@ void Foam::addPatchCellLayer::calcExtrudeInfo
 
             if (otherProci != -1)
             {
-                if (gd[Pstream::myProcNo()].found(otherProci))
+                // Use existing processorPolyPatch to otherProci?
+
+                label procPatchi =
+                    gd.topology().procPatchLookup(otherProci);
+
+                if (procPatchi < 0)
                 {
-                    // There is already a processorPolyPatch to otherProci.
-                    // Use it. Note that we can only index procPatchMap
-                    // if the processor actually is a neighbour processor
-                    // so that is why we first check.
-                    edgePatchID[edgei] = gd.procPatchMap()[otherProci];
-                }
-                else
-                {
-                    // Cannot find a patch to processor. See if already
-                    // marked for addition
-                    if (nbrProcToPatch.found(otherProci))
+                    // No existing processorPolyPatch to otherProci.
+                    // See if already marked for addition
+                    procPatchi = nbrProcToPatch.lookup(otherProci, -1);
+
+                    if (procPatchi < 0)
                     {
-                        edgePatchID[edgei] = nbrProcToPatch[otherProci];
-                    }
-                    else
-                    {
-                        edgePatchID[edgei] = nPatches;
-                        nbrProcToPatch.insert(otherProci, nPatches);
-                        patchToNbrProc.insert(nPatches, otherProci);
-                        nPatches++;
+                        // Add new proc-patch, mark for addition.
+
+                        procPatchi = nPatches;
+                        ++nPatches;
+
+                        nbrProcToPatch.insert(otherProci, procPatchi);
+                        patchToNbrProc.insert(procPatchi, otherProci);
                     }
                 }
+
+                edgePatchID[edgei] = procPatchi;
             }
         }
     }
diff --git a/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.C b/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.C
index 2df0739f11..0c8e68f8f4 100644
--- a/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.C
+++ b/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -23,8 +24,6 @@ License
     You should have received a copy of the GNU General Public License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
-Description
-
 Author
     Hrvoje Jasak
 
@@ -33,16 +32,25 @@ Author
 #include "faGlobalMeshData.H"
 #include "faMesh.H"
 #include "globalMeshData.H"
+#include "processorFaPatch.H"
+#include "processorTopologyNew.H"
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::faGlobalMeshData::faGlobalMeshData(const faMesh& mesh)
 :
-    faProcessorTopology(mesh.boundary(), UPstream::worldComm),
     mesh_(mesh),
+    processorTopology_
+    (
+        processorTopology::New<processorFaPatch>
+        (
+            mesh.boundary(),
+            UPstream::worldComm
+        )
+    ),
     nGlobalPoints_(-1),
-    sharedPointLabels_(0),
-    sharedPointAddr_(0)
+    sharedPointLabels_(),
+    sharedPointAddr_()
 {
     updateMesh();
 }
@@ -50,13 +58,14 @@ Foam::faGlobalMeshData::faGlobalMeshData(const faMesh& mesh)
 
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
+// A non-default destructor since we had incomplete types in the header
 Foam::faGlobalMeshData::~faGlobalMeshData()
 {}
 
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-const Foam::faMesh& Foam::faGlobalMeshData::mesh() const
+const Foam::faMesh& Foam::faGlobalMeshData::mesh() const noexcept
 {
     return mesh_;
 }
diff --git a/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.H b/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.H
index ef4c3e3fed..c494e22f53 100644
--- a/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.H
+++ b/src/finiteArea/faMesh/faGlobalMeshData/faGlobalMeshData.H
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
+    Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,17 +36,17 @@ Author
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef faGlobalMeshData_H
-#define faGlobalMeshData_H
+#ifndef Foam_faGlobalMeshData_H
+#define Foam_faGlobalMeshData_H
 
-#include "faProcessorTopology.H"
+#include "processorTopology.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 namespace Foam
 {
 
-// Class forward declarations
+// Class Declarations
 class faMesh;
 
 /*---------------------------------------------------------------------------*\
@@ -53,25 +54,28 @@ class faMesh;
 \*---------------------------------------------------------------------------*/
 
 class faGlobalMeshData
-:
-    public faProcessorTopology
 {
-    // Private data
+    // Private Data
 
         //- Reference to mesh
         const faMesh& mesh_;
 
-        // Globally shared point addressing
+        //- The processor/processor topology
+        processorTopology processorTopology_;
 
-            //- Total number of global points
-            label nGlobalPoints_;
 
-            //- Indices of local points that are globally shared
-            labelList sharedPointLabels_;
+    // Globally shared point addressing
+
+        //- Total number of global points
+        label nGlobalPoints_;
+
+        //- Indices of local points that are globally shared
+        labelList sharedPointLabels_;
+
+        //- Indices of globally shared points in the master list
+        //  This list contains all the shared points in the mesh
+        labelList sharedPointAddr_;
 
-            //- Indices of globally shared points in the master list
-            //  This list contains all the shared points in the mesh
-            labelList sharedPointAddr_;
 
     // Private Member Functions
 
@@ -87,8 +91,12 @@ public:
     //- Runtime type information
     ClassName("faGlobalMeshData");
 
-    //- Construct from mesh
-    faGlobalMeshData(const faMesh& mesh);
+
+    // Constructors
+
+        //- Construct from mesh
+        explicit faGlobalMeshData(const faMesh& mesh);
+
 
     //- Destructor
     ~faGlobalMeshData();
@@ -96,34 +104,50 @@ public:
 
     // Member Functions
 
-        // Access
+    // Access
 
-            //- Return mesh reference
-            const faMesh& mesh() const;
+        //- Return mesh reference
+        const faMesh& mesh() const noexcept;
 
-        // Globally shared point addressing
 
-            //- Return number of globally shared points
-            label nGlobalPoints() const
-            {
-                return nGlobalPoints_;
-            }
+    // Processor-Topology
 
-            //- Return indices of local points that are globally shared
-            const labelList& sharedPointLabels() const
-            {
-                return sharedPointLabels_;
-            }
+        //- The processor to processor topology.
+        const processorTopology& topology() const noexcept
+        {
+            return processorTopology_;
+        }
 
-            //- Return addressing into the complete globally shared points
-            //  list
-            const labelList& sharedPointAddr() const
-            {
-                return sharedPointAddr_;
-            }
+        //- Order in which the patches should be initialised/evaluated
+        //- corresponding to the schedule
+        const lduSchedule& patchSchedule() const noexcept
+        {
+            return processorTopology_.patchSchedule();
+        }
 
-            //- Change global mesh data given a topological change.
-            void updateMesh();
+
+    // Globally shared point addressing
+
+        //- Return number of globally shared points
+        label nGlobalPoints() const noexcept
+        {
+            return nGlobalPoints_;
+        }
+
+        //- Return indices of local points that are globally shared
+        const labelList& sharedPointLabels() const noexcept
+        {
+            return sharedPointLabels_;
+        }
+
+        //- Return addressing into the complete globally shared points list
+        const labelList& sharedPointAddr() const noexcept
+        {
+            return sharedPointAddr_;
+        }
+
+        //- Change global mesh data given a topological change.
+        void updateMesh();
 };
 
 
diff --git a/src/finiteArea/faMesh/faGlobalMeshData/faProcessorTopology.H b/src/finiteArea/faMesh/faGlobalMeshData/faProcessorTopology.H
deleted file mode 100644
index 607ff448f5..0000000000
--- a/src/finiteArea/faMesh/faGlobalMeshData/faProcessorTopology.H
+++ /dev/null
@@ -1,60 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2016-2017 Wikki 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/>.
-
-Typedef
-    Foam::faProcessorTopology
-
-Description
-
-Author
-    Zeljko Tukovic, FMENA
-    Hrvoje Jasak, Wikki Ltd.
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_faProcessorTopology_H
-#define Foam_faProcessorTopology_H
-
-#include "ProcessorTopology.H"
-#include "processorFaPatch.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-typedef ProcessorTopology<faPatchList, processorFaPatch> faProcessorTopology;
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //
diff --git a/src/finiteArea/faMesh/faPatches/constraint/processor/processorFaPatch.C b/src/finiteArea/faMesh/faPatches/constraint/processor/processorFaPatch.C
index 15f2eb9933..2b3a1a5df9 100644
--- a/src/finiteArea/faMesh/faPatches/constraint/processor/processorFaPatch.C
+++ b/src/finiteArea/faMesh/faPatches/constraint/processor/processorFaPatch.C
@@ -27,6 +27,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "processorFaPatch.H"
+#include "processorPolyPatch.H"  // For newName()
 #include "addToRunTimeSelectionTable.H"
 #include "transformField.H"
 #include "faBoundaryMesh.H"
diff --git a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubset.C b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubset.C
index 2466022c82..fbac703933 100644
--- a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubset.C
+++ b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubset.C
@@ -31,6 +31,7 @@ License
 #include "Pstream.H"
 #include "cyclicPolyPatch.H"
 #include "emptyPolyPatch.H"
+#include "processorPolyPatch.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
diff --git a/src/functionObjects/field/fieldExtents/fieldExtents.C b/src/functionObjects/field/fieldExtents/fieldExtents.C
index f974f3d854..db42a4ac55 100644
--- a/src/functionObjects/field/fieldExtents/fieldExtents.C
+++ b/src/functionObjects/field/fieldExtents/fieldExtents.C
@@ -26,6 +26,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "fieldExtents.H"
+#include "processorPolyPatch.H"
 #include "addToRunTimeSelectionTable.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
diff --git a/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C b/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
index bca349bbfc..0953b39ccd 100644
--- a/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
+++ b/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
@@ -28,6 +28,7 @@ License
 #include "vtkWrite.H"
 #include "cellBitSet.H"
 #include "topoSetCellSource.H"
+#include "processorPolyPatch.H"
 
 // * * * * * * * * * * * * * * Local Data Members  * * * * * * * * * * * * * //
 
diff --git a/src/fvMotionSolver/fvMotionSolvers/displacement/surfaceAlignedSBRStress/surfaceAlignedSBRStressFvMotionSolver.C b/src/fvMotionSolver/fvMotionSolvers/displacement/surfaceAlignedSBRStress/surfaceAlignedSBRStressFvMotionSolver.C
index a888fd225d..954cbd9677 100644
--- a/src/fvMotionSolver/fvMotionSolvers/displacement/surfaceAlignedSBRStress/surfaceAlignedSBRStressFvMotionSolver.C
+++ b/src/fvMotionSolver/fvMotionSolvers/displacement/surfaceAlignedSBRStress/surfaceAlignedSBRStressFvMotionSolver.C
@@ -29,6 +29,7 @@ License
 #include "surfaceAlignedSBRStressFvMotionSolver.H"
 #include "addToRunTimeSelectionTable.H"
 #include "pointIndexHit.H"
+#include "processorPolyPatch.H"
 #include "fvmLaplacian.H"
 #include "fvcDiv.H"
 #include "surfaceInterpolate.H"
diff --git a/src/lagrangian/basic/Cloud/Cloud.C b/src/lagrangian/basic/Cloud/Cloud.C
index 5b7aa9a9f7..a6061e62a7 100644
--- a/src/lagrangian/basic/Cloud/Cloud.C
+++ b/src/lagrangian/basic/Cloud/Cloud.C
@@ -161,7 +161,8 @@ void Foam::Cloud<ParticleType>::move
     const labelList& procPatchNeighbours = pData.processorPatchNeighbours();
 
     // Which processors this processor is connected to
-    const labelList& neighbourProcs = pData[Pstream::myProcNo()];
+    const labelList& neighbourProcs =
+        pData.topology().procNeighbours()[Pstream::myProcNo()];
 
     // Initialise the stepFraction moved for the particles
     for (ParticleType& p : *this)
diff --git a/src/overset/cellCellStencil/trackingInverseDistance/voxelMeshSearch.C b/src/overset/cellCellStencil/trackingInverseDistance/voxelMeshSearch.C
index e775a18e6f..cb2f945587 100644
--- a/src/overset/cellCellStencil/trackingInverseDistance/voxelMeshSearch.C
+++ b/src/overset/cellCellStencil/trackingInverseDistance/voxelMeshSearch.C
@@ -27,11 +27,11 @@ License
 
 #include "voxelMeshSearch.H"
 #include "polyMesh.H"
-#include "processorPolyPatch.H"
 #include "IOobject.H"
 #include "fvMesh.H"
 #include "block.H"
 #include "emptyPolyPatch.H"
+#include "processorPolyPatch.H"
 #include "fvMeshTools.H"
 
 /* * * * * * * * * * * * * * * Static Member Data  * * * * * * * * * * * * * */
diff --git a/src/sampling/meshToMesh/meshToMesh.C b/src/sampling/meshToMesh/meshToMesh.C
index b5404474d5..7fbdda2cc4 100644
--- a/src/sampling/meshToMesh/meshToMesh.C
+++ b/src/sampling/meshToMesh/meshToMesh.C
@@ -31,6 +31,7 @@ License
 #include "globalIndex.H"
 #include "meshToMeshMethod.H"
 #include "nearestFaceAMI.H"
+#include "processorPolyPatch.H"
 #include "faceAreaWeightAMI.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
diff --git a/src/sampling/sampledSurface/sampledFaceZone/sampledFaceZone.C b/src/sampling/sampledSurface/sampledFaceZone/sampledFaceZone.C
index 0132a933e2..9f5c6b167c 100644
--- a/src/sampling/sampledSurface/sampledFaceZone/sampledFaceZone.C
+++ b/src/sampling/sampledSurface/sampledFaceZone/sampledFaceZone.C
@@ -29,6 +29,7 @@ License
 #include "dictionary.H"
 #include "polyMesh.H"
 #include "polyPatch.H"
+#include "processorPolyPatch.H"
 #include "volFields.H"
 #include "surfaceFields.H"
 #include "volPointInterpolation.H"