[R] powerTransform Convergence error

[John Fox]

Dear Brittany,

As explained in ?powerTransform, this function uses optim() to optimize a generalized Box-Cox criterion. For explanation of return codes, see ?optim. 

In particular, code 1 indicates that the maximum number of iterations was exceeded. Although you might try increasing the permitted number of iterations or otherwise tweaking the arguments to optim(), your problem is probably ill-conditioned in some manner that is impossible to know without more information, such as your data.

I hope this helps,
 John

------------------------------------------------
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.mcmaster.ca/jfox/
	

On Wed, 10 Jun 2015 10:54:30 -0600
 Brittany Demmitt <demmitba at gmail.com> wrote:
> Hello,
> 
> I am trying to use the powerTransform function in the package car to identify the lambda: transform my data.  However, I receive the following warning:
> 
> Warning message:
> In estimateTransform(x, y, NULL, ...) :
>   Convergence failure: return code = 1
> 
> I can not find a description of what return code =1  means for the car package.  How do I look that up, or does anyone know what the warning means?
> 
> Thank you so much!
> 
> Brittany
> 	[[alternative HTML version deleted]]
> 
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