Talk:Successive over-relaxation

message: The algorighm section has a k loop and also a superscript k.  I don't think these k's are related, but I'm not sure.  If they are not related, I think we should choose a different variable for the loop.Epachamo 00:26, 3 March 2006 (UTC)
replies: text: They are related: \phi^{(k)} denotes the guess for the solution in the kth iteration. Of course, in a real implementation, one wouldn't keep all the previous φ in memory, but only the current guess. -- Jitse Niesen (talk) 00:37, 3 March 2006 (UTC)
replies: text: That makes sense.  Thanks! Epachamo 05:39, 3 March 2006 (UTC)
thread_title:  Index ''k'' 

message: Can anyone post the time complexity of SOR in detail  —Preceding unsigned comment added by 203.199.213.66 (talk) 11:17, 26 May 2009 (UTC)
thread_title:  Time Complexity 

message: Jack Dongarra's name was only attached to the reference because he uploaded it to netlib. (I'm one of the authors. I know.)  —Preceding unsigned comment added by Eijkhout (talk • contribs) 19:53, 1 December 2010 (UTC)
thread_title:  Attribution 

message: In the section Other applications of the method it says that Richardson extrapolation is the main article for the section. I don't see the connection between the section and Richardson extrapolation; can someone please explain to me what they have to do with each other? —Kri (talk) 22:04, 4 September 2012 (UTC)
thread_title:  "Main article Richardson Extrapolation"? 

message: Both SOR and Gauss-Seidel articles have incorrect algorithms. The Gauss-Seidel article is just the Jacobi method and the algorithm in the SOR article is extrapolated Jacobi. You can easily tell because SOR/Gauss-Seidel should have two inner loops, one that goes from 1 to i-1 and another that goes from i+1 to n.  — Preceding unsigned comment added by 98.27.130.28 (talk) 17:51, 15 August 2013 (UTC)
thread_title:  Algorithm Incorrect 

message: Hi,
I think the description for SSOR is a bit lacking, no examples and some of the variables like gamma are not defined. --Frozenport (talk) 09:36, 12 December 2013 (UTC)
thread_title:  Needs more SSOR 

message: "the system of (...) may be rewritten as" for any $\omega > 1$ this statement is a bit confusing with the following statement where one reads that for convergence, it is necessary for $\omega$ to be $]0,2[$.
As far as I'm aware, the decomposition holds for any $\omega \neq 0$ and a necessary condition for convergence is indeed $|\omega -1|<1$ which for the real case amounts to $\omega\in]0,2[$. I would suggest that someone more expert than me on these questions reviews this. The following paper: http://www.sciencedirect.com/science/article/pii/S0377042700004039 may be a good reference. Thibaut Lienart (talk) 16:47, 17 March 2015 (UTC)
thread_title:  Relaxation parameter 

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thread_title:  External links modified 

message: It seems to me that the formula for the preconditioner in the ssor section is incorrect, I think it should be
:P=\left(\frac{D}{\omega}+L\right)\frac{1}{2-\omega}D^{-1}\left(\frac{D}{\omega}+U\right), or
:P=\left(\frac{D}{\omega}+L\right)\frac{1}{2-\omega}D^{-1}\left(\frac{D}{\omega}+L\right)^T, or
:P=\left(\frac{D}{\omega}+U\right)\frac{1}{2-\omega}D^{-1}\left(\frac{D}{\omega}+U\right)^T, or
:P=\left(\frac{D}{\omega}+U\right)\frac{1}{2-\omega}D^{-1}\left(\frac{D}{\omega}+L\right), but not
:P=\left(\frac{D}{\omega}+L\right)\frac{1}{2-\omega}D^{-1}\left(\frac{D}{\omega}+U\right)^T, the way it is now.  As it is written now, the preconditioner is not symmetric.  If I am correct, let me know and I will make the change to the first display I wrote.  — Preceding unsigned comment added by 2601:404:CF80:1BC4:4DB:96AC:65CD:5042 (talk) 14:51, 18 October 2018 (UTC)
replies: text: Agreed, so I've gone ahead and fixed the formula. 95.144.76.161 (talk) 13:30, 28 December 2018 (UTC)
thread_title:  Formula for Symmetric Successive over-relaxation 

message: I wonder about the choice of the example. The coefficient matrix is not diagonally dominant, it is not even symmetric and positive definite. For some reason it converges fine for the chosen \omega = 0.5, although very slowly.— Preceding unsigned comment added by Mhx (talk • contribs) 06:45, 14 August 2021 (UTC)
thread_title:  Choice of the example