[R] lme convergence

[Dimitris Rizopoulos]

I think the following part of lme.formula

if (numIter > controlvals$maxIter) {
    stop("Maximum number of iterations reached without convergence.")
}


should be something like


if (numIter > controlvals$maxIter) {
    if (controlvals$returnObject) {
        warning("Maximum number of iterations reached without 
convergence.")
        break
    } else {
        stop("Maximum number of iterations reached without 
convergence.")
    }
}


Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Spencer Graves" <spencer.graves at pdf.com>
To: "Ravi Varadhan" <rvaradhan at jhmi.edu>
Cc: "'Pryseley Assam'" <assampryseley at yahoo.com>; "'R-Users'" 
<R-help at stat.math.ethz.ch>; "Douglas Bates" <bates at stat.wisc.edu>
Sent: Friday, June 30, 2006 4:08 AM
Subject: Re: [R] lme convergence


>   Does anyone know how to obtain the 'returnObject' from an 'lme' 
> run
> that fails to converge?  An argument of this name is described on 
> the
> 'lmeControl' help page as, "a logical value indicating whether the
> fitted object should be returned when the maximum number of 
> iterations
> is reached without convergence of the algorithm. Default is 
> 'FALSE'."
>
>   Unfortunately, I've so far been unable to get it to work, as
> witnessed by the following modification of an example from the 
> '?lme'
> help page:
>
> > library(nlme)
> > fm1 <- lme(distance ~ age, data = Orthodont,
> +            control=lmeControl(msMaxIter=1))
> Error in lme.formula(distance ~ age, data = Orthodont, control =
> lmeControl(msMaxIter = 1)) :
> iteration limit reached without convergence (9)
> > fm1
> Error: object "fm1" not found
> > fm1 <- lme(distance ~ age, data = Orthodont,
> +            control=lmeControl(msMaxIter=1,
> +              returnObject=TRUE))
> Error in lme.formula(distance ~ age, data = Orthodont, control =
> lmeControl(msMaxIter = 1,  :
> iteration limit reached without convergence (9)
> > fm1
> Error: object "fm1" not found
>
>   I might be able to fix the problem myself, working through the 
> 'lme'
> code line by line, e.g., using 'debug'.  However, I'm not ready to 
> do
> that just now.
>
>   Best Wishes,
>   Spencer Graves
>
> Ravi Varadhan wrote:
>> Use "try" to capture error messages without breaking the loop.
>> ?try
>>
>> --------------------------------------------------------------------------
>> Ravi Varadhan, Ph.D.
>> Assistant Professor,  The Center on Aging and Health
>> Division of Geriatric Medicine and Gerontology
>> Johns Hopkins University
>> Ph: (410) 502-2619
>> Fax: (410) 614-9625
>> Email:  rvaradhan at jhmi.edu
>> Webpage: 
>> http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html
>> --------------------------------------------------------------------------
>>
>>> -----Original Message-----
>>> From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-
>>> bounces at stat.math.ethz.ch] On Behalf Of Pryseley Assam
>>> Sent: Wednesday, June 28, 2006 12:18 PM
>>> To: R-Users
>>> Subject: [R] lme convergence
>>>
>>> Dear R-Users,
>>>
>>>   Is it possible to get the covariance matrix from an lme model 
>>> that did
>>> not converge ?
>>>
>>>   I am doing a simulation which entails fitting linear mixed 
>>> models, using
>>> a "for loop".
>>>   Within each loop, i generate a new data set and analyze it using 
>>> a mixed
>>> model.  The loop stops When the "lme function" does not converge 
>>> for a
>>> simulated dataset. I want to inquire if there is a method to 
>>> suppress the
>>> error message from the lme function, or better still, a way of 
>>> going about
>>> this issue of the loop ending once the lme function does not 
>>> converge.
>>>
>>>   Thanks in advance,
>>>   Pryseley
>>>
>>>
>>> ---------------------------------
>>>
>>>
>>> [[alternative HTML version deleted]]
>>>
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>>
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