Update README.md

cellular_automaton/wireworld_c/README.md

@@ -26,7 +26,7 @@ The code sample is structured as follows:
  * `world.c`, `world.h`: Initialization of the cellular automaton and associated MPI objects.
    * `world_init`: Domain decomposition and buffer allocation.
    * `world_init_io_type`: Creation of the MPI subarray datatype for I/O.
-   * `world_init_neighborhood`: Identification of neighboring processes, creation of MPI graph communicator.
+   * `world_init_neighborhood`: Identification of neighboring processes, creation of MPI graph communicator and MPI Datatypes for halo exchange.
    * `world_init_persistent_requests`: Initialization of persistent requests for halo data exchange.
 
 ## Release Date