A graph-based heuristic channel router

Abstract

This paper presents the formulation of a graph-based heuristic channel routing algorithm and its implementation. The algorithm uses a vertical constraint digraph to select nets that can be routed on a horizontal track, and uses a horizontal constraint graph and heuristics to decide which of those nets should be routed to obtain an optimal solution. The graph-based model has been selected due to its simplicity and its accurate representation of the routing process. The channel router has been implemented in C on an Apollo DN660 workstation. The router has produced minimum channel height solutions for nine of the twelve examples selected from published literature, using a single set of parameters. By adjusting the parameters slightly, minimum solutions were generated for all twelve examples. In particular, Deutsch's Example was routed in minimum non-dogleg channel height in less than 1.3 seconds on the Apollo workstation.