From 44ed6f1896f39e98cd12cc02a13b180b5128ea2e Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Thu, 13 May 2021 14:21:23 -0400
Subject: [PATCH] don't use provided communicator when LAMMPS was compiled with
 STUBS

---
 src/USER-MDI/library_mdi.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/USER-MDI/library_mdi.cpp b/src/USER-MDI/library_mdi.cpp
index ce7e38754e..6b90da91ff 100644
--- a/src/USER-MDI/library_mdi.cpp
+++ b/src/USER-MDI/library_mdi.cpp
@@ -82,7 +82,11 @@ int MDI_Plugin_init_lammps()
   if (!found_filename) MPI_Abort(MPI_COMM_WORLD, 1);
 
   // create and run a LAMMPS instance
-  auto lmp = lammps_open(mdi_argc, mdi_argv, mpi_world_comm, NULL);
+  void *lmp = nullptr;
+  if (lammps_config_has_mpi_support() > 0)
+    lmp = lammps_open(mdi_argc, mdi_argv, mpi_world_comm, nullptr);
+  else
+    lmp = lammps_open_no_mpi(mdi_argc, mdi_argv, nullptr);
   lammps_file(lmp, filename);
   lammps_close(lmp);