Hi

I keep getting an error like this:

Error in `coef<-.corARMA`(`*tmp*`, value = c(18.3113452983211,
-1.56626248550284,  :
  Coefficient matrix not invertible

or like this:

Error in gls(archlogfl ~ co2, correlation = corARMA(p = 3)) : false
convergence (8)

with the gls function in nlme.

The former example was with the model
"gls(archlogflfornma~nma,correlation=corARMA(p=3))" where archlogflfornma is
"[1] 2.611840 2.618454 2.503317 2.305531 2.180464 2.185764 2.221760
2.211320" and nma is "[1] 138 139 142 148 150 134 137 135".

You can see the model in the latter, and archlogfl is "[1] 2.611840 2.618454
2.503317 2.305531 2.180464 2.185764 2.221760 2.211320 [9] 2.105556 2.176747"
and co2 is "[1]  597.5778  917.9308 1101.0430  679.7803  886.5347  597.0668
873.4995 [8]  816.3483 1427.0190  423.8917".

I'm quite a nube, so sorry, but help most appreciated. I have R 2.13.1.

Roland

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