Visible to Intel only — GUID: GUID-8AE99407-CFB4-47EB-8022-B7BA4A6FE972
Measuring Communication and Computation Overlap
Measuring Pure Communication Time
Iallgather
Iallgather_pure
Iallgatherv
Iallgatherv_pure
Iallreduce
Iallreduce_pure
Ialltoall
Ialltoall_pure
Ialltoallv
Ialltoallv_pure
Ibarrier
Ibarrier_pure
Ibcast
Ibcast_pure
Igather
Igather_pure
Igatherv
Igatherv_pure
Ireduce
Ireduce_pure
Ireduce_scatter
Ireduce_scatter_pure
Iscatter
Iscatter_pure
Iscatterv
Iscatterv_pure
Visible to Intel only — GUID: GUID-8AE99407-CFB4-47EB-8022-B7BA4A6FE972
Communicators, Active Processes
Communicator management is repeated in every “select MY_COMM” step. If it exists, the previous communicator is freed. When you run Q<=P processes, the first Q ranks of MPI_COMM_WORLD are put into one group, and the remaining P-Q get MPI_COMM_NULL.
The group of MY_COMM calls the active processes group.