Efficient Parallel Implementation of a Full Configuration Interaction Algorithm for Circular Polyenes On a Cray Y-Mp

Abstract
An efficient implementation on the CRAY Y-MP of a new full configuration interaction algorithm is illus trated on a model problem. This shows how a careful optimization can lead to huge speedups in CPU times and interesting speedups in the overall elapsed times. The implementation takes full advantage of the algo rithm's characteristics, with a full vectorization of the heaviest innermost loops and parallelization of the im mediately outer loops.