Efficient obstacle-avoiding rectilinear steiner tree construction

Abstract

Abstract-Given a set of pins and a set of obstacles on a plane, an obstacle-avoiding rectilinear Steiner minimal tree (OARSMT) connects these pins, possibly through some additional points (called the Steiner points), and avoids running through any obstacle to construct a tree with a minimal total wirelength. The OARSMT problem becomes more important than ever for modern nanometer IC designs which need to consider numerous routing obstacles incurred from power networks, prerouted nets, IP blocks, feature patterns for manufacturability improvement, antenna jumpers for reliability enhancement, etc. Consequently, the OARSMT problem has received dramatically increasing attention recently. Nevertheless, considering obstacles significantly increases the problem complexity, and thus, most previous works suffer from either poor quality or expensive running time. Based on the obstacle-avoiding spanning graph, this paper presents an efficient algorithm with some theoretical optimality guarantees for the OARSMT construction. Unlike previous heuristics, our algorithm guarantees to find an optimal OARSMT for any two-pin net and many higher pin nets. Extensive experiments show that our algorithm results in significantly shorter wirelengths than all state-of-the-art works.

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

“…In this section, we provide the experimental results on several commonly used test cases [8], [10], [24], [28]. We have implemented our algorithm in C++ language and compiled it using gcc 3.4.6.…”

“…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.…”

Orthogonal Hyperedge Routing

“…These features can also be used interactively from within the Dunnart diagram editor. 6 We have used the orthogonal hyperedge routing algorithms to find routes for a variety of diagrams.…”

“…Computing the MRST is NP-Complete [2] and several heuristics and exact methods are given in [5]. A number of heuristic methods have also been developed for finding obstacle-avoiding rectilinear Steiner minimal trees (OARSMTs) [1,6] for automatic connector routing in VLSI design. Our problem differs from the standard problem studied in the VLSI setting because we are interested in supporting circuit construction in an interactive diagramming tool.…”