Polytope Projects

126 Polytope Projects

6.3 Packing and Unpacking

6.3.1 VLSI Design

Packing is becoming more and more important in very large scale

integration, VLSI physical design because circuit size is growing rapidly

and hierarchical design with blocks is now used widely to reduce the design

complexity. Many packing problems are very complex, so most packing

algorithms use either analytical force-directed methods or perturbations

with random searches and heuristics. Packing representation thus becomes

a fundamental issue since the effi ciency of these basic operations relies on

the geometrical expression of circuit blocks.

There are two important characteristics of an efficient packing

representation.

The fi rst is the number of the combinations of a representation. ...