Parallel computation of molecular energy gradients on the loosely coupled array of processors (LCAP)

The implementation of the HONDO program on the Loosely Coupled Array of Processors (LCAP) parallel computer system assembled in our laboratory is presented. We discuss a general strategy used to maintain a high level of compatibility between the serial version and the parallel version of the code. We report the implementation of energy-gradient calculation for SCF wavefunctions. The integral and integral derivative programs display high parallel efficiency, and so does the SCF part in the case of very large basis sets.