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| Content Provider | Society for Industrial and Applied Mathematics (SIAM) |
|---|---|
| Author | Becker, B. Hotz, G. |
| Copyright Year | 1987 |
| Abstract | The optimal planar layout of planar graphs with respect to the $L_1 $- or $L_2 $-metric leads to NP-hard problems, if one assumes the nodes of the graph to be fixed in the plane (see [FiPa], [Be]).In this paper we consider the (optimal) layout of graphs with fixed boundary (i.e., graphs, where only the nodes of a given cycle of the graph have fixed positions in the plane). The investigated layouts are straight line embeddings in a continuous part of the plane; the cost of a layout is calculated with help of very general cost functions including the pth power of the usual Euclidean distance metric for $p = 2,3, \cdots $ (for short, $l_p $-metric).For a large class of graphs, which, for example, occur in chip layout problems as the abstract structure of switching circuits, we show the existence and uniqueness of the optimal layout.The main part of the paper is concerned with planar graphs. We get an interesting characterization of nonplanar layouts of planar graphs, which shows that the optimal layout of a planar graph is planar or at least quasiplanar. This property makes it possible to decompose the general layout problem into two independent problems: (i) Find a layout of a circuit that is not necessarily planar, but that has an lallowed crossing behaviour. (ii) Fix the crossing points and then optimize the layout. Our theorems show that no new contacts (crossing points) will be generated.In the Appendix we outline some (efficient, polynomial time) methods for the construction of optimal layouts and give as an example the optimal layouts of a recursively defined n-bit adder and multiplier. |
| Starting Page | 946 |
| Ending Page | 972 |
| Page Count | 27 |
| File Format | |
| ISSN | 00975397 |
| DOI | 10.1137/0216061 |
| e-ISSN | 10957111 |
| Journal | SIAM Journal on Computing (SMJCAT) |
| Issue Number | 5 |
| Volume Number | 16 |
| Language | English |
| Publisher | Society for Industrial and Applied Mathematics |
| Publisher Date | 2006-07-31 |
| Access Restriction | Subscribed |
| Subject Keyword | Planar graphs; geometric and topological aspects of graph theory star $l_p $-metric convex point (quasi) planar graph with fixed boundary (optimal) layout Relations with graph theory |
| Content Type | Text |
| Resource Type | Article |
| Subject | Mathematics Computer Science |
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