Comparison of Lanczos with Conjugate Gradient Using Element Preconditioning,
Abstract
Consider Ax = b where A arises from two different applications; (i) from structural analysis, (ii) from incomprehensible fluid flow. A will never be assembled but the operation v yields Av will be carried out using the element by element representation bars the use of triangular factorization. Two different types of preconditioning are examined and each is used in a comparison of the conjugate gradient method and the Lanczos algorithm using partial reortogonalization. It appears that these element by element preconditioners are more powerful than diagonal scaling. Moreover, the cost of maintaining semiorthogonality is well worth paying; the number of iterations is greatly reduced and consequently the extra burden of occasional orthogonalizations never dominated the cost of the solution algorithm in our examples.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1987
- Accession Number
- ADA178098
Entities
People
- A. Raefsky
- B. N. Partlett
- B. Nour-omid
Organizations
- University of California, Berkeley