[R] circular structures in NLME

[Michael Jerosch-Herold]

I have a problem where I am looking at a circular structure and I want
to examine the spatial correlation pattern in the random effects portion
of the model. I am looking at 8 sectors of a circular patch, and plan to
use the corExp class. The sector number is the position variable, but
for the calculation of the distance between two sectors I need to take
into account the fact that the sectors are arranged in a circular
pattern. I have read through some of the NLME documentation, it is not
clear to me how I can specify the "distance function" appropriately.

Any help/suggestions would be much appreciated.

Michael Jerosch-Herold