Is MPI Large or Small?

• MPI is large (125 functions)
  • MPI's extensive functionality requires many functions.
  • Number of functions not necessarily a measure of complexity.
  MPI_ABORT MPI_ADDRESS MPI_ALLGATHER MPI_ALLGATHERV MPI_ALLREDUCE MPI_ALLTOALL MPI_ALLTOALLV MPI_ATTR_DELETE MPI_ATTR_GET MPI_ATTR_PUT MPI_BARRIER MPI_BCAST MPI_BSEND MPI_BSEND_INIT MPI_BUFFER_ATTACH MPI_BUFFER_DETACH MPI_CANCEL MPI_CARTDIM_GET MPI_CART_COORDS MPI_CART_CREATE MPI_CART_GET MPI_CART_MAP MPI_CART_RANK MPI_CART_SHIFT MPI_CART_SUB MPI_COMM_COMPARE MPI_COMM_CREATE MPI_COMM_DUP MPI_COMM_FREE MPI_COMM_GROUP MPI_COMM_RANK MPI_COMM_REMOTE_GROUP MPI_COMM_REMOTE_SIZE MPI_COMM_SIZE MPI_COMM_SPLIT MPI_COMM_TEST_INTER MPI_DIMS_CREATE MPI_ERRHANDLER_CREATE MPI_ERRHANDLER_FREE MPI_ERRHANDLER_GET MPI_ERRHANDLER_SET MPI_ERROR_CLASS MPI_ERROR_STRING MPI_FINALIZE MPI_GATHER MPI_GATHERV MPI_GET_COUNT MPI_GET_ELEMENTS MPI_GET_PROCESSOR_NAME MPI_GRAPHDIMS_GET MPI_GRAPH_CREATE MPI_GRAPH_GET MPI_GRAPH_MAP MPI_GRAPH_NEIGHBORS MPI_GRAPH_NEIGHBORS_COUNT MPI_GROUP_COMPARE MPI_GROUP_DIFFERENCE MPI_GROUP_EXCL MPI_GROUP_FREE MPI_GROUP_INCL MPI_GROUP_INTERSECTION MPI_GROUP_RANGE_EXCL MPI_GROUP_RANGE_INCL MPI_GROUP_RANK MPI_GROUP_SIZE MPI_GROUP_TRANSLATE_RANKS MPI_GROUP_UNION MPI_IBSEND MPI_INIT MPI_INITIALIZED MPI_INTERCOMM_CREATE MPI_INTERCOMM_MERGE MPI_IPROBE MPI_IRECV MPI_IRSEND MPI_ISEND MPI_ISSEND MPI_KEYVAL_CREATE MPI_KEYVAL_FREE MPI_OP_CREATE MPI_OP_FREE MPI_PACK MPI_PACK_SIZE MPI_PCONTROL MPI_PROBE MPI_RECV MPI_RECV_INIT MPI_REDUCE MPI_REDUCE_SCATTER MPI_REQUEST_FREE MPI_RSEND MPI_RSEND_INIT MPI_SCAN MPI_SCATTER MPI_SCATTERV MPI_SEND MPI_SENDRECV MPI_SENDRECV_REPLACE MPI_SEND_INIT MPI_SSEND MPI_SSEND_INIT MPI_START MPI_STARTALL MPI_TEST MPI_TESTALL MPI_TESTANY MPI_TESTSOME MPI_TEST_CANCELLED MPI_TOPO_TEST MPI_TYPE_COMMIT MPI_TYPE_CONTIGUOUS MPI_TYPE_EXTENT MPI_TYPE_FREE MPI_TYPE_HINDEXED MPI_TYPE_HVECTOR MPI_TYPE_INDEXED MPI_TYPE_LB MPI_TYPE_SIZE MPI_TYPE_STRUCT MPI_TYPE_UB MPI_TYPE_VECTOR MPI_UNPACK MPI_WAIT MPI_WAITALL MPI_WAITANY MPI_WAITSOME MPI_WTICK MPI_WTIME
• MPI is small. Many parallel programs can be written with just 6 basic functions.
  • MPI_Init- Initialise MPI.
  • MPI_Comm_size- Find out how many processes there are.
  • MPI_Comm_rank- Find out which process I am.
  • MPI_Send- Send a message.
  • MPI_Recv- Receive a message.
  • MPI_Finalize- Terminate MPI.
• MPI is just right
  • One can access flexibility when it is required.
  • One need not master all parts of MPI to use it.