polyMesh: Ensure parallel consistency in findCell

by ensuring tetBasePtIs is called on all processors, even for those with
0 cells.  Also use unique communicator for globalMeshData to avoid data
transfer interference.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1792

src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C

@@ -2748,7 +2748,12 @@ void Foam::globalMeshData::updateMesh()
 
     // *** Temporary hack to avoid problems with overlapping communication
     // *** between these reductions and the calculation of deltaCoeffs
-    label comm = UPstream::worldComm + 1;
+    label comm = UPstream::allocateCommunicator
+    (
+        UPstream::worldComm,
+        identity(UPstream::nProcs()),
+        true
+    );
 
     // Total number of faces.
     nTotalFaces_ = returnReduce
@@ -2785,6 +2790,8 @@ void Foam::globalMeshData::updateMesh()
         comm
     );
 
+    UPstream::freeCommunicator(comm);
+
     if (debug)
     {
         Pout<< "globalMeshData : nTotalPoints_:" << nTotalPoints_ << endl;

src/OpenFOAM/meshes/polyMesh/polyMesh.C

@@ -1478,7 +1478,11 @@ Foam::label Foam::polyMesh::findCell
     const cellRepresentation decompMode
 ) const
 {
-    if (Pstream::parRun() && decompMode == FACEDIAGTETS)
+    if
+    (
+        Pstream::parRun()
+     && (decompMode == FACEDIAGTETS || decompMode == CELL_TETS)
+    )
     {
         // Force construction of face-diagonal decomposition before testing
         // for zero cells. If parallel running a local domain might have zero
@@ -1500,8 +1504,10 @@ Foam::label Foam::polyMesh::findCell
     {
         return cellI;
     }
-    else // point is not in the nearest cell so search all cells
+    else
     {
+        // point is not in the nearest cell so search all cells
+
         for (label cellI = 0; cellI < nCells(); cellI++)
         {
             if (pointInCell(location, cellI, decompMode))
@@ -1509,6 +1515,7 @@ Foam::label Foam::polyMesh::findCell
                 return cellI;
             }
         }
+
         return -1;
     }
 }