Add an EnsureComm call to make sure things are sane (elemental#182)

include/El/blas_like/level1/Copy/TranslateBetweenGrids.hpp

@@ -3891,6 +3891,7 @@ void TranslateBetweenGrids(
   Int ALDim = A.LDim();
 
   mpi::Comm const& viewingCommB = B.Grid().ViewingComm();
+
   bool const inAGrid = A.Participating();
   bool const inBGrid = B.Participating();
 
@@ -3951,6 +3952,10 @@ void TranslateBetweenGrids(
        ? *maybeMultiSync
        : (inAGrid ? syncInfoA : syncInfoB));
 
+  // Collective!
+  mpi::EnsureComm<T, Collective::SEND>(viewingCommB, syncInfo);
+  mpi::EnsureComm<T, Collective::RECV>(viewingCommB, syncInfo);
+
   // Translate the ranks from A's VC communicator to B's viewing so
   // that we can match send/recv communicators. Since A's VC
   // communicator is not necessarily defined on every process, we