Efficient rectilinear Steiner tree construction with rectilinear blockages

Abstract

Given n points on a plane, a Rectilinear Steiner Minimal Tree (RSM T ) connects these points through some extra points called steiner points to achieve a tree with minimal total wire length. Taking blockages into account dramatically increases the problem complexity. It is extremely unlikely that an efficient optimal algorithm exists for Rectilinear Steiner Minimal Tree Construction with Rectilinear Blockages (RSM T RB). Although there exist some heuristic algorithms for this problem, they have either poor quality or expensive running time.In this paper, we propose an efficient and effective approach to solve RSM T RB. The connection graph we used in this approach is called spanning graph which only contains O(n) edges and vertices. An O(n log n) time algorithm is proposed to construct spanning graph for RSM T RB. The experimental results show that this approach can achieve a solution with significantly reduced wire length. The total run time increased is negligible in the whole design flow.

EBOARST: An Efficient Edge-Based Obstacle-Avoiding Rectilinear Steiner Tree Construction Algorithm

“…Comparison of the quality of the Steiner trees generated by the four algorithms is provided in Table I. Benchmarks IND01∼IND05, RC01∼RC12, RT01∼RT05, and RL01∼RL05 are test cases used in previous works [8], [10], [11], [24]. Benchmarks Adaptec2∼Bigblue4 are based on the placement benchmarks used in ISPD 2005 Placement Contest [28].…”

“…Noticeably, Shen et al [11] have claimed an O(n log n) OASG construction algorithm. These two OASG algorithms, although having the same time complexity and similar outcome, do not share a common structure.…”

“…Three algorithms proposed lately also fall into this category [8], [10], [11]. The connection graph used by Feng et al [8] is the so-called obstacle-avoiding constrained Delaunay triangulation, while in the approaches of Shen et al [11] and Lin et al [10], spanning graphs are used.…”

“…The connection graph used by Feng et al [8] is the so-called obstacle-avoiding constrained Delaunay triangulation, while in the approaches of Shen et al [11] and Lin et al [10], spanning graphs are used. The later steps are common to all: A minimum terminal spanning tree (MTST, defined in Section IV-B) over this connection graph is generated and then refined to become a Steiner tree using heuristics.…”

“…More recent OARSMT heuristics proposed in the literature adopt different strategies [8]- [11], [13]. They mainly fall into two categories.…”