Pars is used to update the coefficients of the model components
  of object and the individual (restricted) log-likelihood
  contributions of each component are added together. The type of
  log-likelihood (restricted or not) is determined by the
  settings attribute of object.
# S3 method for lmeStruct
logLik(object, Pars, conLin, ...)the (restricted) log-likelihood for the linear mixed-effects model
  described by object, evaluated at Pars.
an object inheriting from class "lmeStruct",
   representing a list of linear mixed-effects model components, such as
   reStruct, corStruct, and varFunc objects.
the parameter values at which the (restricted) log-likelihood is to be evaluated.
an optional condensed linear model object, consisting of
   a list with components "Xy", corresponding to a regression
   matrix (X) combined with a response vector (y), and 
   "logLik", corresponding to the log-likelihood of the
   underlying lme model. Defaults to attr(object, "conLin").
some methods for this generic require additional arguments. None are used in this method.
José Pinheiro and Douglas Bates bates@stat.wisc.edu
lme,
  lmeStruct,
  logLik.lme