PARALLEL COMPUTING IN QUANTUM-CHEMISTRY - MESSAGE-PASSING AND BEYOND FOR A GENERAL AB-INITIO PROGRAM SYSTEM

The parallelization of the diagonalization step of the COLUMBUS MRSDCI program system is reported. A coarse grain algorithm has been develop ed by means of a segmentation of the trial and resulting update vector s of the iterative Davidson scheme. Message passing based on the TCGMS G toolkit and the global array (GA) tools are used. The latter program system allows an asynchronous access to data structures in the spirit of shared memory. The importance of portable facilities like GA going beyond message passing is stressed for quantum chemical methods and b enchmark result for the Intel Touchstone Delta are given.