Broadcasts a message from the process with rank root to all other processes of the group.
res = MPI_Bcast(value,rootID[,comm=mpi_comm])
The value to be sent to all nodes.
The source of the message
If the optional argument "comm" is given, this function will use the MPI communicator created by MPI_Create_comm. If not, the default MPI_COMM_WORLD is used.
The broadcasted value. If the optional argument "comm" is given, all nodes which are not in the communicator will return empty matrix.
Send a variable to all nodes. The value should be retrieved by the node with the function MPI_Recv.
On the internal technical side, two broadcasts are used transparently. The first one sends the size of the data, the second the data themself.
MPI_Init(); rnk = MPI_Comm_rank(); sizeNodes = MPI_Comm_size(); SLV = rnk; // handy shortcuts, master is rank 0 Master = ~ SLV; // slaves are all other a=-1 if Master // Declare a a=42 end b=MPI_Bcast(a, 0); assert_checkequal(b,42); MPI_Finalize(); | ![]() | ![]() |