Measured Performance of a Programmed Implementation of the Subscripted D-Algorithm

Hypothesized performance improvements of the subscripted D-Algorithm have now been confirmed by a series of benchmark comparisons with the Roth's DALG. The major concept exploited by the subscripted algorithm is the acquisition of control over a submodule by back-propagation of multiple simultaneously sensitized D /sub j/ paths. The existence of these simultaneously sensitizable control paths has now been verified for many circuits of very large size. The run time required to establsih such control paths is usually about the same as the time that DALG takes to find a single test. Hence, for high fan-in submodules the performance enhancements are impressive. The algorithm readily finds multiple control paths in circuits with high fan-out and reconvergence. The algorithm even backpropagates readily through Exclusive-Or trees. Therefore, apprehension that multiple control paths would suffer mutual interference in practical circuits is not completely justified.