Title :
A Mixed HVH-VHV Algorithm for Three-Layer Channel Routing
Author :
Pitchumani, Vijay ; Zhang, Qisui
Author_Institution :
Syracuse University, ECE Dept., Syracuse, NY, USA
fDate :
7/1/1987 12:00:00 AM
Abstract :
We present a hybrid three-layer channel-routing algorithm that combines horizontal-vertical-horizontal (HVH) and vertical-horizontal-vertical (VHV) approaches [1]. The result is the best of both approaches. VHV excels when the vertical constraint graph (VCG) has long chains; HVH is strong when the VCG has a large number of incomparable nodes. In hybrid routing, the VCG is partitioned into two portions, one ideally suited for HVH and the other for VHV. The portions are routed with a transition track in between. It is shown that, for many channel-routing problems, the hybrid method can do with fewer tracks than the theoretical lower bounds of the algorithms given in [1][2][3]. A heuristic algorithm is given for determining an optimum partitioning into HVH and VHV portions. The algorithm is powerful and its performance on Deutsch´s difficult example [8] is discussed as an illustration.
Keywords :
Design automation; Helium; Heuristic algorithms; NP-complete problem; Partitioning algorithms; Routing;
Journal_Title :
Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
DOI :
10.1109/TCAD.1987.1270297