Electronic Design Automation

11.5.3. Nonquadratic techniques

Another category of analytical approach is to formulate the placement problem as a single nonlinear program as in Section 11.5.1. However, instead of exact wirelength metric and exact nonoverlapping constraints, approximations are used. In particular, the placement region is divided into bins, and the nonoverlapping constraints are replaced by bin density constraints. Let x and y be the vectors of x- and y-coordinates of the modules, respectively. Then the problem can be formulated as follows:WL^e() is a continuously differentiable function that may be more complicated than quadratic functions but may also be more ...