(21) A Parallel Multilayer-Channel Router in CMGTP

We have developed three different programs for the channel routing problem in three different languages, namely, CMGTP, KLIC, and CLP(FD). For Deutsch's problem, the CLP(FD) program not only found all the best solutions already known by now, but also found a solution that has never been found before. The KLIC program succeeded in solving the problem for four different types of channels, but its performance depends to a large extent on the order in which the requirements are given. While the CMGTP program is the shortest one, which essentially consists of only three rules, it failed to solve any large problems. By comparing the three programs, we clarify the advantages and shortcomings of CMGTP, and point out some directions for improving CMGTP.