R devel - Aug 2007 - Bug in coef<-.varIdent method (nlme package) (PR#9831)

Hello,

1. It appears that "coef<-.varIdent" method does not work properly
in
some instances.
Execution error:

Error in `coef<-.varIdent`(`*tmp*`, value = c(11, 12)) :
        Cannot change the length of the varIdent parameter after 
initialization


occurs when  "coef<-.varIdent" is applied to an initialized object
of
class varIdent  with some of the coefficients  being _fixed_.
Attached files: 'varIdentOrthoEmail.txt'  and
'varIdentOrthoEmail.Rout'
illustrate the problem.

2. The code for  "coef<-.varIdentX" method in  
'varIdentmethodsRevised.txt' file  illustrates how to fix this problem.

3. Specifically, to fix the problem the line

       if (length(value) != nGroups  - 1)  

   in  the "coef<-.varIdent" method should be replaced
   with the following two lines :

        nFixed  <- sum(as.numeric(attr(object,"whichFix")))  #
inserted
new line
        if (length(value) != nGroups - nFixed - 1) {               # 
modified original line

4. Note: Although I am using lme "3.1-80", the  related problem
PR#9765
is fixed manually by over-writing varIdent function.

Thank you

Andrzej Galecki