A linear-time heuristic for rectilinear Steiner trees

Rectilinear Steiner spanning trees are used in several phases of the VLSI physical design process when collections of terminals must be connected to a common electrical point. The authors present a new linear time heuristic algorithm for generating these rectilinear Steiner trees. They begin with minimal spanning trees and transform those configurations which are never found in the shortest Steiner trees. This decreases the length of the spanning trees. In addition to its speed, the algorithm is straightforward and can be implemented efficiently. Empirical results demonstrate that reductions of over 13% in length are possible, while an average of over 8% reduction is achieved. This compares very favorably to much more complex algorithms. The algorithm is recommended for applications where many spanning trees are needed in a very short time