Re: [R] nls problem with R

From: Mike Marchywka <marchywka_at_hotmail.com>
Date: Wed, 04 May 2011 11:21:33 -0400

> Date: Wed, 4 May 2011 07:07:44 -0700
> From: sterlesser_at_hotmail.com
> To: r-help_at_r-project.org
> Subject: Re: [R] nls problem with R
>
> Thanks Andrew.
> I am sorry for some typos that I omit some numbers of T2.
> Based on your suggestion,I think the problem is in the initial values.
> And I will read more theory about the non-linear regression.

there is unlikely to be any magic involved, unlike getting hotmail to work. As a tool for understanding your data, you should have some idea of the qualitiative properties of model and data and the error function you use to reconcile the two.

If you can post your full data set I may post an R example of somethings to try. I was looking for an excuse to play with nls, I'm not expert here, and curious to see what I can do with your example for critique by others. If you want to fully automate this for N contnuous parameters, you can take a shotgun approach but not sure it helps other htna to find gross problems in model or data.
I actually wrote a loop to keep picking random parameter values and calculate and SSE between predicted and real data. What you soon find is that this is like trying to decode a good crypto algorithm by guessing- you can do the math to see the problem LOL.

>
> --
> View this message in context: http://r.789695.n4.nabble.com/nls-problem-with-R-tp3494454p3495672.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help_at_r-project.org 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.
                                               



R-help_at_r-project.org 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. Received on Thu 05 May 2011 - 06:25:02 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 05 May 2011 - 09:30:05 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive