Addressed race condition.

Author: odlomax

src/atlas/grid/detail/partitioner/MatchingMeshPartitionerCubedSphere.cc

@@ -33,11 +33,10 @@ void MatchingMeshPartitionerCubedSphere::partition(const Grid& grid, int partiti
     // Loop over grid and set partioning[].
     auto lonlatIt = grid.lonlat().begin();
     atlas_omp_parallel_for(gidx_t i = 0; i < grid.size(); ++i) {
+        const auto& lonLat = *(lonlatIt + i);
         // This is probably more expensive than it needs to be, as it performs
         // a dry run of the cubedsphere interpolation method.
-        const auto& lonlat = *lonlatIt;
-        partitioning[i]    = finder.getCell(lonlat, listSize, edgeEpsilon, epsilon).isect ? mpi_rank : -1;
-        ++lonlatIt;
+        partitioning[i]    = finder.getCell(lonLat, listSize, edgeEpsilon, epsilon).isect ? mpi_rank : -1;
     }
 
     // AllReduce to get full partitioning array.