[R] nls: example code throws error
Greets, I'm trying to learn to use nls and was running the example code for an exponential model: x - -(1:100)/10 y - 100 + 10 * exp(x / 2) + rnorm(x)/10 nlmod - nls(y ~ Const + A * exp(B * x)) Error in B * x : non-numeric argument to binary operator In addition: Warning message: In nls(y ~ Const + A * exp(B * x)) : No starting values specified for some parameters. Initializing Const to '1.'. Consider specifying 'start' or using a selfStart model Presumably, the code should work if it is part of an example on the help page. In perusing various help forums for similar problems, it also appears that others believe this syntax should work in the model formula. Any ideas? Perhaps also, a pointer to a comprehensive and correct document that details model formulae syntax if someone has one? Thanks Best Regards, Steven [[alternative HTML version deleted]] __ R-help@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.
Re: [R] nls: example code throws error
On Thu, Apr 25, 2013 at 7:16 PM, Steven LeBlanc ores...@gmail.com wrote: Greets, I'm trying to learn to use nls and was running the example code for an exponential model: x - -(1:100)/10 y - 100 + 10 * exp(x / 2) + rnorm(x)/10 nlmod - nls(y ~ Const + A * exp(B * x)) Error in B * x : non-numeric argument to binary operator In addition: Warning message: In nls(y ~ Const + A * exp(B * x)) : No starting values specified for some parameters. Initializing ‘Const’ to '1.'. Consider specifying 'start' or using a selfStart model Presumably, the code should work if it is part of an example on the help page. In perusing various help forums for similar problems, it also appears that others believe this syntax should work in the model formula. Any ideas? Try running in a clean session. Having B - X in your workspace would cause such an error. -- Statistics Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com __ R-help@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.
Re: [R] nls: example code throws error
Hi Try x - -(1:100)/10 set.seed(1) y - 100 + 10 * exp(x / 2) + rnorm(x)/10 short cut to starting values lm(log(y) ~-log(x+10)) Call: lm(formula = log(y) ~ -log(x + 10)) Coefficients: (Intercept) 4.624 nlmod - nls(y ~ A + B * exp(C * x), start=list(A=90, B=5,C=0.1)) Formula: y ~ A + B * exp(C * x) Parameters: Estimate Std. Error t value Pr(|t|) A 100.009079 0.017797 5619.4 2e-16 B 9.93 0.042718 234.1 2e-16 C 0.499529 0.004495 111.1 2e-16 Residual standard error: 0.09073 on 97 degrees of freedom Number of iterations to convergence: 5 Achieved convergence tolerance: 0.0002475 I will leave you to plot the results as a check Duncan Duncan Mackay Department of Agronomy and Soil Science University of New England Armidale NSW 2351 Email: home: mac...@northnet.com.au At 09:16 26/04/2013, you wrote: Content-Type: text/plain Content-Disposition: inline Content-length: 899 Greets, I'm trying to learn to use nls and was running the example code for an exponential model: x - -(1:100)/10 y - 100 + 10 * exp(x / 2) + rnorm(x)/10 nlmod - nls(y ~ Const + A * exp(B * x)) Error in B * x : non-numeric argument to binary operator In addition: Warning message: In nls(y ~ Const + A * exp(B * x)) : No starting values specified for some parameters. Initializing 'Const' to '1.'. Consider specifying 'start' or using a selfStart model Presumably, the code should work if it is part of an example on the help page. In perusing various help forums for similar problems, it also appears that others believe this syntax should work in the model formula. Any ideas? Perhaps also, a pointer to a comprehensive and correct document that details model formulae syntax if someone has one? Thanks Best Regards, Steven [[alternative HTML version deleted]] __ R-help@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@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.
Re: [R] nls: example code throws error
On 26/04/2013 00:16, Steven LeBlanc wrote: Greets, I'm trying to learn to use nls and was running the example code for an exponential model: snip Perhaps also, a pointer to a comprehensive and correct document that details model formulae syntax if someone has one? Thanks Best Regards, Steven Others have pointed out that the error is probably from an unclean environment. For model formula syntax, see ?nls Under Arguments formula, follow the link to ?formula __ R-help@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.
Re: [R] nls: example code throws error
Keith Jewell k.jewell at campden.co.uk writes: Others have pointed out that the error is probably from an unclean environment. Completely OT, but an unclean environment sounds sort of scary to me. Like it contains zombies or something. I don't know a better, short way to express the idea though. __ R-help@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.
Re: [R] nls: example code throws error
On 13-04-26 10:14 AM, Ben Bolker wrote: Keith Jewell k.jewell at campden.co.uk writes: Others have pointed out that the error is probably from an unclean environment. Completely OT, but an unclean environment sounds sort of scary to me. Like it contains zombies or something. Isn't that accurate? Undead objects causing your code to be full of bugs? Duncan Murdoch I don't know a better, short way to express the idea though. __ R-help@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@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.
