The orientation of modules based on graph decomposition

Author

Cheng, C.K. ; Yao, S.Z. ; Hu, T.C.

Author_Institution

Dept. of Comput. Sci. & Eng., California Univ., San Diego, La Jolla, CA, USA

Volume

40

Issue

6

fYear

1991

fDate

6/1/1991 12:00:00 AM

Firstpage

774

Lastpage

780

Abstract

In the layout stage of VLSI and printed circuit board (PCB) design, after all circuit modules (rectangular) are placed, it is possible to flip the modules so as to reduce the total net length. The authors formulate the orientation of modules as a graph problem and prove it to be NP-complete. The orientation problem is shown to be equivalent to finding a minimum cut of a graph with some arcs of negative capacities. In many cases, the graph can be decomposed into subgraphs to reduce the search space for optimum orientation. Experiments with real cases show that module orientation reduces the total net length and improves the routability

Keywords

VLSI; circuit layout CAD; computational complexity; graph theory; printed circuits; NP-complete; VLSI; graph decomposition; graph problem; layout stage; minimum cut; modules; orientation; printed circuit board; routability; total net length; Algorithm design and analysis; Clocks; Delay effects; Distributed computing; Hardware; Matrix decomposition; Parallel processing; Systolic arrays; Transmission line matrix methods; Very large scale integration;

fLanguage

English

Journal_Title

Computers, IEEE Transactions on

Publisher

ieee

ISSN

0018-9340

Type

jour

DOI

10.1109/12.90255

Filename

90255