Talk:Limited-memory BFGS

message: It would be nice if the LBFGS article and the BFGS article used the same symbol to represent the approximation to the inverse of the Hessian. LBFGS uses Hk and BFGS uses Bk^{-1}  — Preceding unsigned comment added by 76.102.204.220 (talk) 03:52, 26 March 2014 (UTC)

message: The intention when creating this page was to give software information. Our hope is that users can contribute links to versions of L-BFGS written in different languages. There are various explanations of the L-BFGS algorithm on the web and there is no need for another one here. Therefore I will try to restore the earlier version. Nocedal 06:53, 2 December 2007 (UTC)
replies: text: Thanks for contributing, but Wikipedia is not a collection of links. It is an online encyclopedia, and while links to software packages for L-BFGS are certainly relevant and worth including, this entry is not here simply to advertise software packages; the Wikipedia entry on L-BFGS should first and foremost be a discussion the algorithm. If no further objection/elaboration is raised, I'm going to re-add the algorithm information and reformat the article to conform with Wikipedia standards. --Soultaco (talk) 04:58, 6 December 2007 (UTC)
thread_title:  software information back 

message: in the sentence "An early, open source implementation of L-BFGS in Fortran exists" I would expect some citation and/or link to this reference that seems important. No?  —Preceding unsigned comment added by Orzelf (talk • contribs) 22:38, 20 February 2010 (UTC)
thread_title:  Citation needed?

message: The sign of initial z seems to be wrong here:
 H^0_k=  \gamma_k I
 z = -H^0_k q
Nocedal's Numerical Optimization has a positive sign. (Alg 7.4, page 178)
I tried implementing the version listed here and it does not converge on Rosenbrock.  — Preceding unsigned comment added by 136.152.250.167 (talk) 00:16, 23 January 2019 (UTC)
replies: text: I was wandering about the same thing. But following your interpretation makes H^0_k a **scalar** matrix, so by abuse of notation one might say that the pseudo code is in fact correct? But then surely there should be a better approximation of H^0_k that uses a diagonal non-scalar matrix, right? bungalo (talk) 11:00, 15 April 2017 (UTC)
thread_title:  Bug in algorithm? 

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thread_title:  External links modified 

message: I don't understand the point of introducing the matrix H^0_k in the algorithm. It is just a scaled identity matrix, so why not simply multiply z by \gamma_k?
-- Andrew Myers (talk) 22:37, 25 August 2019 (UTC)
thread_title:  Algorithm description