From efc3810d49d1263a5b89411e19ee5b5f9dfbd339 Mon Sep 17 00:00:00 2001
From: Henry Weller <http://cfd.direct>
Date: Sun, 13 Sep 2015 22:12:12 +0100
Subject: [PATCH] globalMeshData: Changed the communicator for the reductions
 Avoids problems with overlapping communicationbetween these reductions and
 the calculation of deltaCoeffs.  This is a temporary fix while code
 reorganizations are undertaken to ensure the globalMeshData is updated before
 deltaCoeffs are requested.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1780
---
 .../polyMesh/globalMeshData/globalMeshData.C  | 28 +++++++++++++++++--
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
index 2739e828..e54fefcc 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
@@ -2746,22 +2746,44 @@ void Foam::globalMeshData::updateMesh()
         Pout<< "globalMeshData : merge dist:" << tolDim << endl;
     }
 
+    // *** Temporary hack to avoid problems with overlapping communication
+    // *** between these reductions and the calculation of deltaCoeffs
+    label comm = UPstream::worldComm + 1;
+
     // Total number of faces.
-    nTotalFaces_ = returnReduce(mesh_.nFaces(), sumOp<label>());
+    nTotalFaces_ = returnReduce
+    (
+        mesh_.nFaces(),
+        sumOp<label>(),
+        Pstream::msgType(),
+        comm
+    );
 
     if (debug)
     {
         Pout<< "globalMeshData : nTotalFaces_:" << nTotalFaces_ << endl;
     }
 
-    nTotalCells_ = returnReduce(mesh_.nCells(), sumOp<label>());
+    nTotalCells_ = returnReduce
+    (
+        mesh_.nCells(),
+        sumOp<label>(),
+        Pstream::msgType(),
+        comm
+    );
 
     if (debug)
     {
         Pout<< "globalMeshData : nTotalCells_:" << nTotalCells_ << endl;
     }
 
-    nTotalPoints_ = returnReduce(mesh_.nPoints(), sumOp<label>());
+    nTotalPoints_ = returnReduce
+    (
+        mesh_.nPoints(),
+        sumOp<label>(),
+        Pstream::msgType(),
+        comm
+    );
 
     if (debug)
     {