Patches contributed by Mattijs Janssens:

splitMeshRegions: handle flipping of faces for surface fields

subsetMesh: subset dimensionedFields

decomposePar: use run-time selection of decomposition constraints. Used to
    keep cells on particular processors. See the decomposeParDict in

$FOAM_UTILITIES/parallel/decomposePar:
  - preserveBaffles: keep baffle faces on same processor
  - preserveFaceZones: keep faceZones owner and neighbour on same processor
  - preservePatches: keep owner and neighbour on same processor. Note: not
    suitable for cyclicAMI since these are not coupled on the patch level
  - singleProcessorFaceSets: keep complete faceSet on a single processor
  - refinementHistory: keep cells originating from a single cell on the
    same processor.

decomposePar: clean up decomposition of refinement data from snappyHexMesh

reconstructPar: reconstruct refinement data (refineHexMesh, snappyHexMesh)

reconstructParMesh: reconstruct refinement data (refineHexMesh, snappyHexMesh)

redistributePar:
  - corrected mapping surfaceFields
  - adding processor patches in order consistent with decomposePar

argList: check that slaves are running same version as master

fvMeshSubset: move to dynamicMesh library

fvMeshDistribute:
  - support for mapping dimensionedFields
  - corrected mapping of surfaceFields

parallel routines: allow parallel running on single processor

Field: support for
  - distributed mapping
  - mapping with flipping

mapDistribute: support for flipping

AMIInterpolation: avoid constructing localPoints

src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -36,8 +36,8 @@ SourceFiles
 #define decompositionMethod_H
 
 #include "polyMesh.H"
-#include "pointField.H"
 #include "CompactListList.H"
+#include "decompositionConstraint.H"
 
 namespace Foam
 {
@@ -56,6 +56,8 @@ protected:
         const dictionary& decompositionDict_;
         label nProcessors_;
 
+        //- Optional constraints
+        PtrList<decompositionConstraint> constraints_;
 
 private:
 
@@ -98,14 +100,7 @@ public:
     // Constructors
 
         //- Construct given the decomposition dictionary
-        decompositionMethod(const dictionary& decompositionDict)
-        :
-            decompositionDict_(decompositionDict),
-            nProcessors_
-            (
-                readLabel(decompositionDict.lookup("numberOfSubdomains"))
-            )
-        {}
+        decompositionMethod(const dictionary& decompositionDict);
 
 
     //- Destructor
@@ -226,6 +221,19 @@ public:
                 CompactListList<label>& cellCells
             );
 
+            //- Helper: determine (local or global) cellCells and face weights
+            //  from mesh agglomeration.
+            //  Uses mag of faceArea as weights
+            static void calcCellCells
+            (
+                const polyMesh& mesh,
+                const labelList& agglom,
+                const label nLocalCoarse,
+                const bool parallel,
+                CompactListList<label>& cellCells,
+                CompactListList<scalar>& cellCellWeights
+            );
+
             //- Helper: extract constraints:
             //  blockedface: existing faces where owner and neighbour on same
             //               proc
@@ -241,6 +249,19 @@ public:
                 List<labelPair>& explicitConnections
             );
 
+            //- Helper: apply constraints to a decomposition. This gives
+            //  constraints opportunity to modify decomposition in case
+            //  the native decomposition method has not obeyed all constraints
+            void applyConstraints
+            (
+                const polyMesh& mesh,
+                const boolList& blockedFace,
+                const PtrList<labelList>& specifiedProcessorFaces,
+                const labelList& specifiedProcessor,
+                const List<labelPair>& explicitConnections,
+                labelList& finalDecomp
+            );
+
             // Decompose a mesh with constraints:
             // - blockedFace : whether owner and neighbour should be on same
             //   processor