Command-line options for c_mpi

Command-line options for c_mpi

When ncptl is passed --backend=c_mpi as a command-line option, c_mpi processes the following backend-specific command-line options:

--ssend

In the generated code, MPI_Isend() and MPI_Irecv() are used for asynchronous communication and MPI_Send() and MPI_Recv() are normally used for synchronous communication. However, the c_mpi-specific compiler option --ssend instructs c_mpi to replace all calls to MPI_Send() in the generated code with calls to MPI_Ssend(), MPI’s synchronizing send function. A program’s log files indicate whether the program was built to use MPI_Send() or MPI_Ssend() .

--reduce=MPI_Op

The default reduction operation is MPI_SUM but a different operation can be specified using the c_mpi-specific --reduce compiler option. A program’s log files indicate the reduction operation that was used.