By Topic

Highly Efficient Gradient Computation for Density-Constrained Analytical Placement

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
Cong, J. ; Dept. of Comput. Sci., Univ. of California at Los Angeles, Los Angeles, CA ; Guojie Luo ; Radke, E.

Recent analytical global placers use density constraints to approximate nonoverlap constraints, and these show very successful results. This paper unifies a wide range of density smoothing techniques called global smoothing and presents a highly efficient method for computing the gradient of such smoothed densities used in several well-known analytical placers. This method reduces the complexity of the gradient computation by a factor of n compared with a naive method, where n is the number of modules. Furthermore, with this efficient gradient computation, it is able to support an efficient nonlinear programming-based placement framework, which supersedes the existing force-directed placement methods. Experiments show that replacing the approximated gradient computation in mPL6 with the exact gradient computation improves wire length by 15% on the IBM-HB+ benchmark and by 3% on average on the modified International Symposium on Physical Design 2005 (ISPD'05) and ISPD'06 placement contest benchmarks with movable macros. The results also show that the augmented Lagrangian method outperforms the quadratic penalty method with the exact gradient computation.

Published in:

Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on  (Volume:27 ,  Issue: 12 )