Fast obstacle-avoiding octilinear steiner minimal tree construction algorithm for VLSI design

With advance in manufacturing technology, 45ºand 135º diagonal segments can be permitted in an octilinear routing model. In this article, we present a heuristic algorithm to solve obstacle-avoiding octilinear Steiner minimal tree (OAOSMT) construction problem. We first construct an obstacle-free Euclidean minimal spanning tree (OFEMST). Then two lookup tables about OFEMST's edge are generated, which can provide fast information inquiry for subsequent steps. Next, an obstacle-avoiding strategy is proposed to convert OFEMST into an obstacle-avoiding octilinear Steiner tree (OAOST). Finally, we design an excellent refinement technique, which can further reduce the wirelengh. Experiments show that both wirelengh and runtime of our algorithm are the best compared to the previous algorithms.