Abstract
Obstacle-avoiding rectilinear Steiner minimal tree (OARSMT) construction is becoming one of the most sought after problems in modern design flow. In this paper we present FOARS, an algorithm to route a multi-terminal net in the presence of obstacles. FOARS is a top down approach which includes partitioning the initial solution into subproblems and using obstacle aware version of Fast Lookup Table based Wire-length Estimation (OA-FLUTE) at a lower level to generate an OAST followed by recombining them with some backend refinement. To construct an initial connectivity graph FOARS uses a novel obstacle-avoiding spanning graph (OASG) algorithm which is a generalization of Zhou's spanning graph algorithm without obstacle [1]. FOARS has a run time complexity of O(n log n). Our experimental results indicate that it outperforms Lin et al. [2] by 2.3% in wirelength. FOARS also has 20% faster run time as compared with Long et al. [3], which is the fastest solution till date. Copyright 2010 ACM.