The Rest of the World?
MPI_Comm_size(MPI_COMM_WORLD,&P);
MPI_Comm_rank(MPI_COMM_WORLD,&my_id);
Note: pass address of variables!
MPI_COMM_WORLD
- called a communicator
- collection of processes that can communicate
- predefined in MPI
- consists of all the processes running when execution begins