>>>>> "KateM" == Katharine Mullen <[EMAIL PROTECTED]>
>>>>> on Fri, 7 Sep 2007 20:07:41 +0200 (CEST) writes:
KateM> The thread you linked to regarding Levenberg-Marquardt's supposed
lack of
KateM> availability is from 2001; it has been possible to get
KateM> to the MINPACK implementation of Levenberg-Marquardt within R via the
KateM> package minpack.lm
KateM> (http://cran.r-project.org/src/contrib/Descriptions/minpack.lm.html)
since
KateM> 2005.
Thanks a lot, Kate.
I'm wondering about experiences:
Do you know of cases where minpack.lm's nls.lm() solved a
(real) problem that nls() would have a problem with ?
Beware however -- one of the main things I learned about this
field from Doug Bates, co-author of Bates_and_Watts and
prinicipal author of S's and R's nls() :
It's a *feature* that nls() does not converge sometimes when
other methods do falsely claim convergence!
Martin Maechler, ETH Zurich
KateM> ----
KateM> Katharine Mullen
KateM> mail: Department of Physics and Astronomy, Faculty of Sciences
KateM> Vrije Universiteit Amsterdam, de Boelelaan 1081
KateM> 1081 HV Amsterdam, The Netherlands
KateM> room: T.1.06
KateM> tel: +31 205987870
KateM> fax: +31 205987992
KateM> e-mail: [EMAIL PROTECTED]
KateM> homepage: http://www.nat.vu.nl/~kate/
KateM> On Fri, 7 Sep 2007, Jose Luis Aznarte M. wrote:
>> Hi! I'm translating some code from Matlab to R and I found a problem.
>> I need to translate Matlab's function 'lsqnonlin'
>> (http://www-ccs.ucsd.edu/matlab/toolbox/optim/lsqnonlin.html) into R,
>> and at the beginning I thought it would be the same as R's 'optim'. But
>> then I looked at the definition of 'lsqnonlin' and I don't quite see how
>> to make 'optim' to do the same thing. Does anyone have an idea?
>> This is apart from the fact that I would like to use the Levenberg
>> Marquardt algorithm which is not implemented in R (some discussion about
>> this: http://tolstoy.newcastle.edu.au/R/help/00b/2492.html).
>> Thank you! All the best,
>>
>>
>> -- --
>> Jose Luis Aznarte M. http://decsai.ugr.es/~jlaznarte
>> Department of Computer Science and Artificial Intelligence
>> Universidad de Granada Tel. +34 - 958 - 24 04 67
>> GRANADA (Spain) Fax: +34 - 958 - 24 00 79
>>
>> ______________________________________________
>> R-help@stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
KateM> ______________________________________________
KateM> R-help@stat.math.ethz.ch mailing list
KateM> https://stat.ethz.ch/mailman/listinfo/r-help
KateM> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
KateM> and provide commented, minimal, self-contained, reproducible code.
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