In a message dated 12/25/2003 3:00:34 PM Pacific Standard Time, 
ripley@stats.ox.ac.uk writes:
>You are trying to fit a loess curve to just five points: that is not 
>sensible (and interpolates in S-PLUS, so I don't think it `works' there 
>either).
>

Thanks for the quick reply.  
 
>Loess in R is not the same as loess in S-PLUS.  (The latter is
>proprietary, and loess in R was implemented as a wrapper for the released
>C/Fortran code from the same group of authors.)  You could have tried
>looking at the warnings, the first four of which are
>
>1: pseudoinverse used at 13
>2: neighborhood radius 1
>3: reciprocal condition number  0
>4: There are other near singularities as well. 1
>
>and indicate that there were problems in doing the loess fit.

I looked at the warnings and saw that there was a problem, but wasn't sure if 
that was due to a syntax error, or some other problem.  I assumed that the 
code had been run successfully before (obviously an incorrect assumption in this 
case).

>
>What did you (or the authors) want here?  It is hard to think of a useful 
>visualization of the pattern of 5 points beyond linear interpolation.

In looking at the textbook, it looks like all the authors wanted was to see 
some general profile of responses over time.  It probably would be just as 
useful (maybe more so) to just join the points with line segments.

>
>
>BTW, you want library(lattice) and not library(nlme).  In 1.8.1 
>nlme attaches lattice, but in the next release it will not do so.

I was aware that nlme attaches lattice, but it is good to know that I will 
have to do that explicitly in the near future..

Thanks again,

Dan Nordlund

	[[alternative HTML version deleted]]


