HPL_all_reduce All reduce operation.


#include "hpl.h"

int HPL_all_reduce( void * BUFFER, const int COUNT, const HPL_T_TYPE DTYPE, const HPL_T_OP OP, MPI_Comm COMM );


HPL_all_reduce 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.

See Also

HPL_broadcast, HPL_reduce, HPL_barrier, HPL_min, HPL_max, HPL_sum.