Algorithms for the equilibration of matrices and their application to limited-memory quasi-newton methods

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Abstract/Contents

Abstract
Diagonally scaling a matrix can reduce its condition number. Equilibration scales a matrix so that the row and column norms are equal. We review the existence and uniqueness theory for exact equilibration. Then we introduce a formalization of approximate equilibration and develop its existence and uniqueness theory. Next we develop approximate equilibration algorithms that access a matrix only by matrix-vector products. We address both the nonsymmetric and symmetric cases. Limited-memory quasi-Newton methods may be thought of as changing the metric so that the steepest-descent method works effectively on the problem. Quasi-Newton methods construct a matrix using vectors of two types involving the iterates and gradients. The vectors are related by an approximate matrix-vector product. Using our approximate matrix-free symmetric equilibration method, we develop a limited-memory quasi-Newton method in which one part of the quasi-Newton matrix approximately equilibrates the Hessian. Often a differential equation is solved by discretizing it on a sequence of increasingly fine meshes. This technique can be used when solving differential-equation-constrained optimization problems. We describe a method to interpolate our limited-memory quasi-Newton matrix from a coarse to a fine mesh.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2010
Issuance monographic
Language English

Creators/Contributors

Associated with Bradley, Andrew Michael
Associated with Stanford University, Department of Computational and Mathematical Engineering.
Primary advisor Murray, Walter
Thesis advisor Murray, Walter
Thesis advisor Saunders, Michael A
Thesis advisor Ye, Yinyu
Advisor Saunders, Michael A
Advisor Ye, Yinyu

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Andrew Michael Bradley.
Note Submitted to the Department of Computational and Mathematical Engineering.
Thesis Ph. D. Stanford University 2010
Location electronic resource

Access conditions

Copyright
© 2010 by Andrew Michael Bradley
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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