Merge branch release-2016

[alexxy/gromacs.git] / src / gromacs / mdtypes / commrec.h

diff --git a/src/gromacs/mdtypes/commrec.h b/src/gromacs/mdtypes/commrec.h
index 37cab123b418ddb1e488e11fb261f0b7422f5b57..cdbf2b9e235dda703b39c4a4b8a81efcd9da2cf9 100644 (file)
--- a/src/gromacs/mdtypes/commrec.h
+++ b/src/gromacs/mdtypes/commrec.h
@@ -94,8 +94,14 @@ struct t_commrec {
     /* Not used yet: int threadid, nthreads; */
     /* The nodeid in the PP/PME, PP or PME group */
     int      nodeid;
-    MPI_Comm mpi_comm_mysim;
-    MPI_Comm mpi_comm_mygroup;
+
+    /* MPI communicators within a single simulation
+     * Note: other parts of the code may further subset these communicators.
+     */
+    MPI_Comm mpi_comm_mysim;           /* communicator including all ranks of
+                                          a single simulation */
+    MPI_Comm mpi_comm_mygroup;         /* subset of mpi_comm_mysim including only
+                                          the ranks in the same group (PP or PME) */
 
     /* MPI ranks and a communicator within a physical node for hardware access */
     MPI_Comm       mpi_comm_physicalnode; /* communicator for all ranks of the physical node