From ripley at stats.ox.ac.uk  Mon Sep 13 18:58:53 2004
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Mon Sep 13 18:58:56 2004
Subject: [Rd] Problem with mle in stats4 (R 1.9.1)
In-Reply-To: <003c01c499ac$82016290$82b98283@DH>
Message-ID: <Pine.LNX.4.44.0409131750290.22504-100000@gannet.stats>

We are currently on R 2.0.0 alpha.  If you submit a bug fix, preferably 
this week and at the latest next week, it will be considered for 2.0.0.

Please take seriously that R is an open project and does not have `staff' 
to fix bugs.  If you think it is worth fixing, please fix it for us
by providing a complete analysis and fixes for all the possible options 
that might be affected.

The best place for a patch to be sent is R-bugs.

On Mon, 13 Sep 2004, Daniel Hoppe wrote:

> Hi!
> 
> This is a repost of an earlier message (with a clearer example
> demonstrating the problem I ran into). If you run the mle example in
> stats4
> 
>      library(stats4)
>      x <- 0:10
>      y <- c(26, 17, 13, 12, 20, 5, 9, 8, 5, 4, 8)
>      ll <- function(ymax=15, xhalf=6)
>          -sum(stats::dpois(y, lambda=ymax/(1+x/xhalf), log=TRUE))
>      (fit <- mle(ll))
>      plot(profile(fit), absVal=FALSE)
> 
> everything works fine. Now run 
> 
>      (fit <- mle(ll, method="BFGS", control=list(ndeps=c(1e-3, 1e-3))))
>      plot(profile(fit), absVal=FALSE)
> 
> and you will get
> 
> Error in interpSpline.default(obj[[i]]$par.vals[, i], obj[[i]]$z,
> na.action = na.omit) : 
>         only 0's may mix with negative subscripts
> 
> This happens because optim gets the old ndeps but just one variable to
> optimize. The optim error is not reported, so the problem is rather hard
> to trace. Would you agree that this would be worth fixing?
> 
> Best regards,
> 
> Daniel
> 
> (original posting with quick workaround
> http://tolstoy.newcastle.edu.au/R/help/04/07/1778.html)
> 
> --
> Daniel Hoppe
> Department of Marketing
> University of Vienna
> Bruenner Strasse 72
> 1210 Vienna
> Austria
> 
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
> 

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


[Rd] Problem with mle in stats4 (R 1.9.1)
Prof Brian Ripley