[R-sig-phylo] nlme, gls regression errors

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

Re: [R-sig-phylo] follow up for lambda transform - query: how to use an existing covariance matrix directly in a gls procedure in R?

Hi Luke. For a fixed value of lambda this is very easy. For this example, you would just do: library(ape) data(bird.orders) dat-data.frame(y=rnorm(23),x=rnorm(23)) rownames(dat)-bird.orders$tip.label mat-vcv(bird.orders,cor=TRUE) # following Blomberg to here lambda-0.75 # for instance