coxme: model simplification using LR-test?

Summary of the query: "update" does not work on a coxme object

 I ran into this bug myself 2 days ago -- I rarely use update() so
hadn't encountered it before.  The problem is that coxme breaks the
formula into fixed and random portions, and this confuses the default
method for formula.

Solution: add the following function:
  formula.coxme <- function(x, ...) x$call$formula

 This method will be included in my next update of coxme.

Terry Therneau