The following predefined operations are supplied for MPI_REDUCE and related functions MPI_ALLREDUCE, MPI_REDUCE_SCATTER, and MPI_SCAN. These operations are invoked by placing the following in op.
reduce, list of operations MPI_MAX MPI_MIN MPI_SUM MPI_PROD MPI_LAND MPI_BAND MPI_LOR MPI_BOR MPI_BXOR MPI_MAXLOC MPI_MINLOC MPI_LXOR
The two operations MPI_MINLOC and MPI_MAXLOC are
discussed separately in Section 
.
For the other predefined operations,
we enumerate below the allowed combinations of op and
datatype arguments.
First, define groups of MPI basic datatypes
in the following way.
