Improved approximation bounds for the group Steiner problem

C.S. Helvig, G. Robins, A. Zelikovsky
Proceedings Design, Automation and Test in Europe  
Given a weighted g r aph and a family of k disjoint groups of nodes, the Group Steiner Problem asks for a minimum-cost routing tree that contains at least one node from each group. We give polynomial-time Ok -approximation algorithms for arbitrarily small values of 0 , improving on the previously known Ok 1 2 -approximation. Our techniques also solve the graph Steiner arborescence p r oblem with an Ok approximation bound. These results are directly applicable to a practical problem in VLSI
more » ... roblem in VLSI layout, namely the routing of nets with multi-port terminals. Our Java implementation is available on the Web. 1 The performance r atio is an upper bound on the ratio of a heuristic solution cost divided by the optimal solution cost.
doi:10.1109/date.1998.655889 dblp:conf/date/HelvigRZ98 fatcat:ht4rzk77xbfr7g5wwjt7bzoabm