decomposed cyclics handling

src/OpenFOAM/fields/pointPatchFields/constraint/processor/processorPointPatchField.C

@@ -100,15 +100,32 @@ void processorPointPatchField<Type>::initSwapAdd(Field<Type>& pField) const
 {
     if (Pstream::parRun())
     {
+        // Get internal field into my point order
         Field<Type> pf(this->patchInternalField(pField));
 
-        OPstream::write
+        // Normally points will be ordered same on both sides due to
-        (
+        // the point numbering by decomposePar. However this will not be
-            Pstream::blocking,
+        // the case for meshes changed in parallel.
-            procPatch_.neighbProcNo(),
+
-            reinterpret_cast<const char*>(pf.begin()),
+        // Reorder into neighbour point order. Note that one side can have
-            pf.byteSize()
+        // more or less points than other side if partically decomposed
-        );
+        // cyclics are present.
+
+        const labelList& nbrPts = procPatch_.procPolyPatch().neighbPoints();
+
+        Field<Type> nbrf(this->size(), pTraits<Type>::zero);
+
+        forAll(nbrPts, i)
+        {
+            label nbrPointI = nbrPts[i];
+            if (nbrPointI >= 0 && nbrPointI < nbrf.size())
+            {
+                nbrf[nbrPointI] = pf[i];
+            }
+        }
+
+        OPstream toNbr(Pstream::blocking, procPatch_.neighbProcNo());
+        toNbr << nbrf;
     }
 }
 
@@ -119,23 +136,26 @@ void processorPointPatchField<Type>::swapAdd(Field<Type>& pField) const
     if (Pstream::parRun())
     {
         Field<Type> pnf(this->size());
-
+        {
-        IPstream::read
+            // We do not know the number of points on the other side
+            // so cannot use Pstream::read.
+            IPstream fromNbr
             (
                 Pstream::blocking,
-            procPatch_.neighbProcNo(),
+                procPatch_.neighbProcNo()
-            reinterpret_cast<char*>(pnf.begin()),
-            pnf.byteSize()
             );
+            fromNbr >> pnf;
+        }
+
+        pnf.setSize(this->size(), pTraits<Type>::zero);
 
         if (doTransform())
         {
+            const processorPolyPatch& ppp = procPatch_.procPolyPatch();
+            const tensorField& forwardT = ppp.forwardT();
             const labelList& nonGlobalPatchPoints =
                 procPatch_.nonGlobalPatchPoints();
-
-            const processorPolyPatch& ppp = procPatch_.procPolyPatch();
             const labelListList& pointFaces = ppp.pointFaces();
-            const tensorField& forwardT = ppp.forwardT();
 
             if (forwardT.size() == 1)
             {