Iterative Synthesis Techniques for Multiple-Valued Logic Functions A Review and Comparison

A number of heuristics for near optimal functional synthesis of Multi-Valued Logic (MVL) have been reported in the literature. Among the well-known heuristics is the Direct Cover algorithm (DCA). We have introduced a number of improved versions of the DCA. These include the Weighted Direct Cover (WDC), the Ordered Direct Cover (ODC), and the Fuzzy Direct Cover (FDC). In this paper, we review and compare the performance of those heuristic iterative techniques using two set of benchmarks. The first consists of 50000 randomly generated 2-varaible 4-valued functions and the second consists of 50000 2-variable 5-valued functions. The average number of product terms required to synthesize a given MVL function is used as the criterion for comparison. The results obtained show that the modified iterative synthesis heuristics outperformed the DCA and that among the modified techniques the FDC produces the best results.