Marjorie Bourgoin

2000-May-15 09:33 UTC

### [R] Non linear regression using Levenberg-Marquardt method

Hello, I want to fit some non linear models with the Levenberg-Marquardt algorithm. It doesn''t seem to exist any function to do this in R ( well, maybe one does, but I''m a new user, and the only documentation I have is "An introduction to R"). I''d like to know if this function exists, maybe throught an additionnal package. I''d also like to know if if I can fit my models without giving initial estimates of the parameters. The problem is that I have to fit four non linear models with a lots of data sets, so I can''t plot the data and guess parameters values for each of them. Thanks for all Marjorie -- ************************************************************************ BOURGOIN Marjorie CEA Saclay Departement d''Ingenierie et d''Etude des Proteines Bat. 152 91191 GIF sur YVETTE FRANCE Tel:01-69-08-71-35 mbourgoi at salome.saclay.cea.fr ************************************************************************ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._

Thomas Lumley

2000-May-15 15:28 UTC

### [R] Non linear regression using Levenberg-Marquardt method

On Mon, 15 May 2000, Marjorie Bourgoin wrote:> Hello, > > I want to fit some non linear models with the Levenberg-Marquardt > algorithm. It doesn''t seem to exist any function to do this in R ( well, > maybe one does, but I''m a new user, and the only documentation I have is > "An introduction to R"). > I''d like to know if this function exists, maybe throught an additionnal > package.The nls package fits many non-linear models. Some of them are ''self-starting''; they don''t need starting values. Even if your model isn''t one of them you might be able to work out how to make it self-starting. I don''t think it uses a Levenberg-Marquardt algorithm, but that shouldn''t matter. You could also code the model as a minimisation problem and feed it to optim(), which also doesn''t use a Levenberg-Marquardt model. -thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._