In this paper, the authors propose a simple deterministic algorithm for solving the very large scale integration (VLSI) block placement problem, which considers the packing area and interconnect wiring simultaneously. The algorithm is based on the so-called less flexibility first (LFF) principle, which relies on an old Chinese rule-of-thumb in stone packing work. The principle simply states a priority order in selecting empty space inside a working area to be filled by packed blocks.

I found it very interesting that the authors were motivated in their approach by the accumulated experience of ancient professionals in solving similar problems. Based on this LFF principle, they develop their heuristic algorithm for block placement, and demonstrate how to pack blocks with the least packing flexibility in their shape and interconnect requirements into the empty space with the least packing flexibility, in a greedy manner.

The authors provide a satisfactory literature review of existing relevant research, and a detailed description of their algorithm and its implementation. In addition, in order to examine the algorithm’s efficiency, they applied their algorithm (implemented using the C programming language) to the Microelectronics Center of North Carolina University (MCNC) benchmark circuits. The authors analyze both the weaknesses and strengths of their approach, and present the experimental results obtained in a comparative way. In general, the results seem to be quite satisfactory and promising.

In conclusion, this is an interesting research work that is well written and documented, and is intended for professionals in the field of VLSI design.