[R] AR1 in gls function

[Prodromos Zanis]

Dear R-project users

I would like to calculate a linear trend versus time taking into account a
first order autoregressive process of a single time series (e.g. data$S80
in the following example) using th gls function.

gls(S80 ~ tt,data=data,corAR1(value, form, fixed))

My question is what number to set in the position of value within corAR1?
Should it be the acf at lag 1?

I look forward for your reply

With kind regards

Prodromos Zanis




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Dr. Prodromos Zanis
Centre for Atmospheric Physics and Climatology
Academy of Athens
3rd September 131, Athens 11251, Greece
Tel. +30 210 8832048
Fax: +30 210 8832048
e-mail: pzanis at geol.uoa.gr
Web address: http://users.auth.gr/~zanis/