Re: [R] newbie nls question

From: Simon Blomberg <s.blomberg1_at_uq.edu.au>
Date: Wed, 11 Jun 2008 09:04:56 +1000

On Tue, 2008-06-10 at 16:56 -0600, Ranney, Steven wrote:
> I'm tyring to fit a relatively simple nls model to some data, but keep coming up against the same error (code follows):
>
> Oto=nls(Otolith ~ Linf*(1-exp(-k(AGE-to))),
> data = ages,
> start = list(Linf=1000, k=0.1, to=0.1),
> trace = TRUE)

Try putting a * in after the k in the formula.

Simon.

>
> The error message I keep getting is "Error in eval(expr, envir, enclos) : could not find function "k"". I've used this line of code for other nls models (with different data, parameter estimates, etc.), but have never gotten this error. The data is
>
> AGE,Otolith,Scale
> 1,207.1052632,207.1052632
> 2,329.962963,332.7586207
> 3,401.9473684,406
> 4,422,413.1111111
> 5,452.6785714,458.34375
> 6,510.75,533
> 7,477,674
> 8,643,704
> 9,,615
> 10,695.5,
> 12,615,
>
> Are the missing values (e.g., no value for Otolith, AGE 9) having an effect? I am using Tinn-R as an editor
>
> I'm new to R, trying to get away from Rcmdr (though it has been helpful), and still trying to learn the language with the aid of several books on the R. A search of the R Archive did not prove fruitful.
>
> Thanks in advance,
>
> SR
>
> Steven H. Ranney
> Graduate Research Assistant (Ph.D)
> USGS Montana Cooperative Fishery Research Unit
> Montana State University
> PO Box 173460
> Bozeman, MT 59717-3460
>
> phone: (406) 994-6643
> fax: (406) 994-7479
>
>
> [[alternative HTML version deleted]]
>
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-- 
Simon Blomberg, BSc (Hons), PhD, MAppStat. 
Lecturer and Consultant Statistician 
Faculty of Biological and Chemical Sciences 
The University of Queensland 
St. Lucia Queensland 4072 
Australia
Room 320 Goddard Building (8)
T: +61 7 3365 2506
http://www.uq.edu.au/~uqsblomb
email: S.Blomberg1_at_uq.edu.au

Policies:
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2.  Your deadline is your problem.

The combination of some data and an aching desire for 
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be extracted from a given body of data. - John Tukey.

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Received on Tue 10 Jun 2008 - 23:38:11 GMT

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