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Home | Seminars and Symposia | Past seminars/symposia: Thursday, March 14, 2002

DTC Seminar Series

Krylov-Subspace Methods for Reduced-Order Modeling In Circuit Simulation


Roland W. Freund
Bell Laboratories

Thursday, March 14, 2002
3:35 p.m. — Room 108 ME,
Unite Channel A

4:35 p.m. — Refreshments EE/CSci

5th Floor Lounge

In recent years, there has been a lot of interest in using Krylov-subspace techniques, such as the Lanczos process, to generate reduced-order models of large-scale time-invariant linear dynamical systems, especially in circuit simulation. However, in circuit simulation, these techniques are mostly applied to passive circuits or subcircuits, such as RLC networks that model the interconnect or the package of an integrated circuit, and usually, it is crucial that the reduced-order model preserves the passivity of the original system. In this talk, Dr. Freund will explain why and how Krylov-subspace methods are employed to generate reduced-order models of large-scale multi-input multi-output linear dynamical systems. We discuss various desirable and in part conflicting properties of the reduced-order models, such as high approximation accuracy, stability, and passivity. We show how to achieve these properties by means of Krylov-subspace iterations, combined with suitable post-processing techniques. Numerical results for a variety of examples from VLSI circuit simulation are presented.