Module placement with pre-placed modules using the corner block list representation

In this paper, we present two methods for module placement with pre-placed modules. The algorithms are based on the corner block list representation. In the first method only free modules are included in each corner block list. While placing each free module from a given corner block list, the method checks for overlaps with pre-placed modules and removes the overlaps by shifting the free module to the right or to the top. The second method includes all modules in each comer block list. If a newly inserted free module overlaps with a pre-placed module, it is swapped with the pre-placed module in the comer block list. If the newly inserted module is a pre-placed module but not in its pre-placed location, we defer the placement of pre-placed module and swap it with the next free module in the comer block list to place at the current location. The first algorithm runs in O (n×p) time and the second algorithm runs in O((n+p)×p) time where n is the number of free modules and p is the number of pre-placed modules. The algorithms are combined with the simulated annealing technique. The experimental results show effectiveness of these algorithms.