Elsevier

Integration

Volume 12, Issue 3, December 1991, Pages 339-352
Integration

Minimal stretching of a layout to ensure 2-layer wirability

https://doi.org/10.1016/0167-9260(91)90029-KGet rights and content

Abstract

Given a (square grid based) wire layout, we present a new approach to the problem of minimally stretching it in order to transform it into a 2-layer wirable one. For knockknee mode wire layouts this approach leads to a linear runtime algorithm if only 1-dimensional stretching is allowed (cf. [1]). When wire segments are allowed to overlap, we show that the decision problem as to whether a wire layout can be stretched in one dimension such that it will be 2-layer wirable is solvable in runtime O(W), where W is the sum of the wire lengths of the layout. However, it is NP-hard to minimize the number of horizontal tracks one has to insert. For the case of 2-dimensional stretching we show that it is NP-hard to minimize the total number of vertical and horizontal tracks necessary to ensure 2-layer wirability even for knockknee mode layouts. The techniques used in the paper are based on a graph-theoretical approach presented in [2,3].

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  • Wiring Knock-Knee Layouts: A Global Approach

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Research supported by DFG, SFB124, TP B1/B2, VLSI Entwurfsmethoden und Parallelität, Lehrstuhl Prof. Dr. Mehlhorn & Lehrstuhl Prof. Dr. Hotz.

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