We consider non-uniform wire-sizing for general routing trees under the Elmore delay model. Three minimization objectives are studied: 1) total weighted sink-delays; 2) total area subject to sink-delay bounds; and 3) maximum sinkdelay. We rst present an algorithm NWSA-wd for minimizing total weighted sink-delays based on iteratively applying the wire-sizing formula in [1]. We show that NWSA-wd always converges to an optimal wire-sizing solution. Based on NWSA-wd and the Lagrangian relaxation technique, we obtained two algorithms NWSA-db and NWSA-md which can optimally solve the other two minimization objectives. Experimental results show that our algorithms are ecient both in terms of runtime and storage. For example, NWSAwd, with linear runtime and storage, can solve a 6201-wire
Chung-Ping Chen, Hai Zhou, D. F. Wong