On VHV-routing in channels with irregular boundaries

A description is given of the VHV-channel-routing problem in irregular channels. The authors describe a branch-and-bound algorithm for finding optimal solutions for this problem. The algorithm partitions the channels into boxes and searches for the optimal among the various mappings of the horizontal net segments to the boxes. The authors discuss three different branching strategies for the algorithm. Heuristic algorithms based on the branching strategies are also discussed. It is also shown that VHV routing is NP-hard for irregular channels