A provable near-optimal algorithm for the channel pin assignment problem

A near-optimal algorithm for the channel pin assignment problem is presented. This algorithm, called the alternative packing algorithm, can always produce an assignment solution whose density is at most one more than the density of an optimal solution, i.e., d(S)⩽d(S*)+1, where d( S) is the density of this solution and d(S*) is the density of the optimal solution. The algorithm is tested on a number of channel routing benchmark examples and achieved significant reduction in channel density and total net span. The algorithm has important applications to the pin assignment and global routing problems in general cell layout design since it is shown that the combined pin assignment and global routing problem can be reduced to a series of channel pin assignment problems