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VLSI Design
Volume 7 (1998), Issue 4, Pages 385-399

Macro-Cell Placement for Custom-Chip Design Using Self-Organizing Fuzzy Technique

1lnstitute of Information Science, Academia Sinica, Taiwan, Taipei, China
2Department of Computer and Information Science, National Chiao Tung University, 1001 Ta Hsueh Rd., Taiwan, Hsinchu 30050, China

Received 9 March 1993; Accepted 28 June 1995

Copyright © 1998 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In this paper, a new optimization technique called SOFT(self-organizing fuzzy technique) is proposed to solve the macro-cell placement problem. In SOFT, different criteria are simultaneously accounted by a novel fuzzy gain function which models expert knowledge to control the optimization process. The presented procedure is an adaptation of Kohonen's self-organization algorithm which is well suited for implementation on massively parallel architecture for fast computing. The MCNC benchmark examples are presented to verify the performance and feasibility of SOFT. Comparisons are made with the Hopfield network, SOAP and TimberWolf MC5.6. Experiments show that the proposed method yields an average of 17% improvement in total wire length compared with previous methods. Large size problems with 225 and 1024 arbitrarily-sized macrocells are also presented.