[R] Warning message in scatter.smooth (modreg)

[Prof Brian Ripley]

On Tue, 1 Jul 2003, Gavin Simpson wrote:

> Dear list,
> 
> In using the scatter.smooth() function (modreg) on a small data set (100 
> obs) the following error was produced:
> 
>  > scatter.smooth(Na, S)
> Warning message:
> k-d tree limited by memory. ncmax= 200
> 
> I haven't used scatter.smooth much but when I have, I haven't seen this 
> message before.
> 
> gc() returns
> 
>  > gc()
>           used (Mb) gc trigger (Mb)
> Ncells 417693 11.2     667722 17.9
> Vcells 103949  0.8     786432  6.0
> 
> This is on a Win XP box with 512 MB RAM, with plenty of space still 
> available (Task Manager Reports 216 MB of RAM and pagefile in use).
> 
> I have looked through the help files for loess and loess.control but 
> didn't see anything about ncmax.  Can someone explain why I might be 
> getting this warning?

It's trying to fit a very complicated function, and running out of its own 
internal storage, which is set in the C routine loess_workspace.  However, 
200 cells should be ample for 100 obs, so I guess the algorithm is not
working properly in your example.

-- 
Brian D. Ripley,                  ripley at 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