A fast algorithm for routability testing

An L-shaped routing of a two-terminal net is its upper- or lower routing Given a set of nets: the planar testability problem (PTP) Is to decide if there exists a planar (i.e., pairwise non-crossing) L-shaped routing of all nets. PTP was solved via transformation to 2-satisfiability. Here, we propose an efficient greedy algorithm running in O(n(logn)/sup 2/, where n is the number of nets. The density-1 testability problem (D1TP) is to decide if there exists an L-shaped routing of all nets with density 1 (i.e., overlap routing is not allowed, however routed nets may intersect each other). We extend-the PTP algorithm to solve the D1TP problem in O(nlogn) time.