VLSI fast initial placement with abutment constraints and L-shaped/T-shaped blocks based on less flexibility first principles

The placement algorithm based on less flexibility first (LFF) principles is a deterministic algorithm obtained through a human's accumulated experience. Experimental results demonstrate that the algorithm is effective and promising in a building block layout application. Through encoded directional graph representation, we have enhanced the LFF principles to handle blocks with abutment constraints and L/T-shaped blocks. The proposed method is demonstrated experimentally by a benchmark and the performance shows the efficiency and effectiveness of the method.