FULL CONFIGURATION-INTERACTION ALGORITHM ON A MASSIVELY-PARALLEL ARCHITECTURE - DIRECT-LIST IMPLEMENTATION

A parallel full configuration interaction (FCI) code, implemented on a distributed memory MPP computer, has been modified in order to use a direct algorithm to compute the lists of mono-and biexcitations each t ime they are needed. We were able to perform FCI calculations on the g round state of the acetylene molecule with two different basis sets, c orresponding to more than 2.5 and 5 billion Slater determinants, respe ctively. The calculations were performed on a Cray-T3D and a Cray-T3E, both machines having 128 processors. Performance and comparison betwe en the two computers are reported and discussed. (C) 1998 John Wiley & Sons, Inc.