Problem getting loess tricubic weights

As this does not seem to have been answered...

I believe you may misunderstand how loess works. The tricube weights
are part of the smoothing algorithm and change with each local fit,
not fixed weights for observations, which is what the "weights"
argument provides (and initially multiplies the tricube weight, IIRC).

I suggest you consult

?predict.loess

to get standard deviations of fitted values at existing or new points.

-- Bert

Hi

I am trying to get the tricube weights from the loess outputs as I need to
calculate an error function which requires the weight.

So I have used the following example from the R:

cars.lo <- loess(dist ~ speed, cars, span=0.5, degree=1, family="symmetric")

Then i try to get the weights:

cars.lo$weights
 [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1

The results are all 1 so i dont think that the tricube weighting are set.
May I know what other parameters do i need to tweak to set the weights to
tricube weights? Thank you.


--
Best regards
Joyce Lin

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130109/3cb8407e/attachment-0001.pl>

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130110/0a3c1059/attachment-0001.pl>

An embedded and charset-unspecified text was scrubbed...
Name: not available
URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130111/aa1817d2/attachment-0001.pl>