All Reduce



next up previous contents
Next: Reduce-Scatter Up: Global Reduction Operations Previous: MINLOC and MAXLOC

All Reduce

  all reduce

MPI includes variants of each of the reduce operations where the result is returned to all processes in the group. MPI requires that all processes participating in these operations receive identical results.

MPI_Allreduce(void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype, MPI_Op op, MPI_Comm comm)

MPI_ALLREDUCE(SENDBUF, RECVBUF, COUNT, DATATYPE, OP, COMM, IERROR) <type> SENDBUF(*), RECVBUF(*)
INTEGER COUNT, DATATYPE, OP, COMM, IERROR

Same as MPI_REDUCE except that the result appears in the receive buffer of all the group members.



Jack Dongarra
Fri Sep 1 06:16:55 EDT 1995