 Hi,

I have confirmed temporal correlation problems in my data. Is there a 
possibility to use corCompSymm for a gamm()?
I am an R-beginner.

I have very short time series. There are three years and within each year, 
there are 10 weeks. he 10 weeks are the same every year and have not unique 
values, I seem not to be able to use AR-1 (I assume that I have too little 
data for autoregression models of higher orders (ARMA)).  If I rename weeks 
as week 1-week 30 to get unique identifiers, I loose the seasonal and 
year-specific effect in the final model.

      M2c.gamm <- gamm(het ~ s(LN.DIN, k=3) + s(LN.totn, k=3) + s(Ncell, 
k=3) + s(LN.biom) + s(temp, k=3) + s(week, k=3)
     + fstation + fyear, method = "ML",
     weights = varIdent(form=~1 | fstation),
     data = data1,
     correlation = corCompSymm(form = ~ week|year))    #seems not to work in 
a gamm()

Thank you for your time!
Anna Zakrisson Braeunlich
PhD Student

Department of Systems Ecology
Stockholm University
Svante Arrheniusv. 21A
SE-106 91 Stockholm

E-mail: anna@ecology.su.se
Tel work: +46 (0)8 161103
Mobile: +46-(0)700-525015
Web site: http://www.ecology.su.se/staff/personal.asp?id=163

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