Generalized Manhattan path algorithm with applications

The author presents an efficient algorithm for finding a route interconnecting two terminals of arbitrary polygonal shape in two layers. The main feature of the router to be distinguished from the existing grid-free routers is that it can handle large vias. The author has also considered the extension to multi-terminal nets and demonstrate a native algorithm which repeats the same path finding process for each constituent terminal. Careful considerations may lead to a more efficient way such that three regions (horizontal and vertical routable regions and via acceptable region) are not reconstructed each time but updated only around the path obtained. In order to do that a data structure has been devised which can implement insertions and deletions of line segments each in O(log n) time. Based on the proposed algorithm it is possible to solve a practical problem which is concerned with a layout design of bipolar LSIs. In this case the purpose is to find an orthogonal wiring route of predetermined width between pairs of terminals avoiding polygonal obstacles in two layers