[R] manual recreation of varConstPower using new fixed effects variables in nlme

[Douglas Bates]

> PS:  Can anyone tell me what the reStruct parameter
> means?  In looking at the verbose output, I obtain a
> reStruct parameter value of -0.8352462 (this is for my
> grouping factor for the random effect).  Does anyone
> know what it means?  The actual value of my single
> random effect is different, as is its variance.

IIRC it is the logarithm of the relative precision of the random effects.