Force directed self-organizing map and its application to VLSI cell placement

A self-organizing map is described. It is called the force directed self-organizing map (FDSOM), and can be used in VLSI cell placement with various constraints on connection and dimension, such that the total wire length and area of the resulting placement are minimized. This procedure combines ideas from force-directed relaxation and the self-organization algorithm proposed by Kohonen. It is particularly suited for such a self-organization problem when those (input) sample vectors are not easily available. A proof of convergence for this model is given. With this property, it can be used in CAM or any other computational task. The experimental results obtained are quite encouraging. All these processes are convergent in a reasonable number of iterations. It is found that the proposed approach is competitive with state-of-the-art algorithms, and uses fewer nodes and connection weights