HPL_all_reduce All reduce operation.
performs a global reduce operation across all
processes of a group leaving the results on all processes.
BUFFER (local input/global output) void *
On entry, BUFFER points to the buffer to be combined. On
exit, this array contains the combined data and is identical
on all processes in the group.
COUNT (global input) const int
On entry, COUNT indicates the number of entries in BUFFER.
COUNT must be at least zero.
DTYPE (global input) const HPL_T_TYPE
On entry, DTYPE specifies the type of the buffers operands.
OP (global input) const HPL_T_OP
On entry, OP is a pointer to the local combine function.
COMM (global/local input) MPI_Comm
The MPI communicator identifying the process collection.