eprintid: 13654 rev_number: 8 eprint_status: archive userid: 353 dir: disk0/00/01/36/54 datestamp: 2016-08-09 14:55:37 lastmod: 2021-08-27 17:27:35 status_changed: 2016-08-09 14:55:37 type: article metadata_visibility: show item_issues_count: 2 creators_name: Nazareth, J. creators_id: AL1035 title: Analogues of Dixon’s and Powell’s Theorems for Unconstrained Minimization with Inexact Line Searches ispublished: pub abstract: Dixon’s theorem (Math. Programming, 2 (1972), PP. 383–387) states that all variable metric methods in the Broyden class develop identical iterates when line searches are exact. Powell’s theorem (Rep. TP 495, AERE, Harwell, England, 1972) is a variant on this, which states that under similar conditions, the Hessian approximation developed by a BFGS update at any step is independent of the updates used at earlier steps. By modifying the way in which search directions are defined, we show how to remove the restrictive assumption on line searches in these two theorems. We show also that the BFGS algorithm, modified in this way, is equivalent to the three-term-recurrence (TTR) method on quadratic functions. Algorithmic implications are discussed and the results of some numerical experimentation are reported. date: 1986-02 date_type: published publisher: Society for Industrial and Applied Mathematics id_number: 10.1137/0723012 creators_browse_id: 2226 full_text_status: none publication: SIAM Journal on Numerical Analysis volume: 23 number: 1 pagerange: 170-177 refereed: TRUE issn: 0036-1429 coversheets_dirty: FALSE fp7_project: no fp7_type: info:eu-repo/semantics/article citation: Nazareth, J. (1986). Analogues of Dixon’s and Powell’s Theorems for Unconstrained Minimization with Inexact Line Searches. SIAM Journal on Numerical Analysis 23 (1) 170-177. 10.1137/0723012 .