Issue No.05 - May (1994 vol.43)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/12.280805
<p>Presents a global approach to solve the three-layer wirability problem for knock-knee layouts. In general, the problem is NP-complete. Only for very restricted classes of layouts polynomial three-layer wiring algorithms are known up to now. The authors show that for a large class of layouts a three-layer wiring can be constructed by solving a path problem in a special class of graphs or a two-satisfiability problem, and thus may be wired in time linear in the size of the layout area. Moreover, it is shown that a minimum stretching of the layout into a layout belonging to this class can be found by solving a clique cover problem in an interval graph. This problem is solvable in time linear in the size of the layout area as well. Altogether, the method also yields a good heuristic for the three-layer wirability problem for knock-knee layouts.</p>
circuit layout CAD; network routing; algorithm theory; knock-knee layouts; three-layer wirability problem; NP-complete; three-layer wiring; two-satisfiability problem; layout area; clique cover problem.
M. Sarrafzadeh, D. Wagner, F. Wagner, K. Weihe, "Wiring Knock-Knee Layouts: A Global Approach", IEEE Transactions on Computers, vol.43, no. 5, pp. 581-589, May 1994, doi:10.1109/12.280805