+ explicit SimulationContext(MPI_Comm worldCommunicator,
+ ArrayRef<const std::string> multiSimDirectoryNames);
+
+ /*!
+ * \brief MPI communicator object for this GROMACS instance.
+ *
+ * With real MPI,
+ * the gmx wrapper binary has called MPI_Init, thus
+ * MPI_COMM_WORLD is now valid to use, and
+ * (in future) the gmxapi runner will handle such details
+ * (e.g. via mpi4py) before creating its SimulationContext.
+ *
+ * With thread-MPI in both cases, the communicator is set up later
+ * during the process of spawning the threads that will be the MPI
+ * ranks. (Multi-simulation is not supported with thread-MPI.)
+ */
+ MPI_Comm worldCommunicator_ = MPI_COMM_NULL;