The "nlme" package has "corExp" for estimating the nuggett
effect
n and the range d for an exponential spatial correlation structure = n +
(1-n)*exp(-r/d), where r = distance between two observations. See
library(nlme); ?corExp, plus Pinheiro and Bates (2000) Mixed-Effects
Models for S and S-Plus (Springer).
Is this what you want?
hope this helps.
spencer graves
p.s. If this is NOT adequate, please read the posting guide!
"http://www.R-project.org/posting-guide.html". This might help you
answer some questions for yourself, thereby getting you quicker answers
than otherwise. Moreover, it could increase your chances of getting a
response that actually helps solve your problem. In particular, please
provide a toy example showing something that a reader can easily copy
from an email and paste into R to try something just a little different.
TRAMIER Blaise wrote:
>Hello,
> I have been asked to perform a exponential correlation on a data set.
>Unfortunately, i did not find any simple example on how to do that with R.
>If the correlation is significant, one asked me to also find the thresold
>of the acceleration slope.
>
>Have any of you a little example or a good link to get me started?
>
>Best regards
>
>Blaise
>
>
--
Spencer Graves, PhD, Senior Development Engineer
O: (408)938-4420; mobile: (408)655-4567