The Distributed Data Interface in GAMESS

The Distributed Data Interface to permit storage of large data arrays in the aggregate memory of distributed memory, message passing computer systems is described. The design of this relatively small library is discussed, in regard to its implementation over SHMEM, MPI-1, or socket based message libraries. The good performance of a MP2 program using DDI is demonstrated on both PC and workstation cluster computers, and some details of the resulting message traffic are presented.