In this paper we describe how one can represent a unitary rank structured matrix in an efficient way as a product of elementary unitary or Givens transformations. We also provide some basic operations for manipulating the representation, such as the transition to zero-creating form, the transition t
Eigenvalue computation for unitary rank structured matrices
β Scribed by Steven Delvaux; Marc Van Barel
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 286 KB
- Volume
- 213
- Category
- Article
- ISSN
- 0377-0427
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β¦ Synopsis
In this paper we describe how to compute the eigenvalues of a unitary rank structured matrix in two steps. First we perform a reduction of the given matrix into Hessenberg form, next we compute the eigenvalues of this resulting Hessenberg matrix via an implicit QR-algorithm. Along the way, we explain how the knowledge of a certain 'shift' correction term to the structure can be used to speed up the QR-algorithm for unitary Hessenberg matrices, and how this observation was implicitly used in a paper due to William B. Gragg. We also treat an analogue of this observation in the Hermitian tridiagonal case.
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