Control the Iteration in lme()
USAGE: 
lme.control(maxiter = 50, ms.maxiter = 50,
           tolerance=1e-6, ms.tolerance=1e-7,
           scale = lme.scale, verbose = F, ms.verbose = F)
OPTIONAL ARGUMENTS:
maxiter:
maximum number of iterations during fit. Default is 50.
ms.maxiter:
maximum number of iterations for the ms() call. Default is 50.
tolerance:
tolerance for the convergence criterion in the algorithm. Default is 1e-6.
ms.tolerance:
tolerance for the convergence criterion in ms(), passed as the rel.tolerance argument to the function (see documentation on ms()). Default is 1e-7.
scale:
scale function passed as the scale argument to the ms() function (see documentation on that function). Default is lme.scale.
verbose:
if T (TRUE) information on the evolution of the iterative algorithm (number of iterations, convergence criterion, etc.) will be printed. Default is F.
ms.verbose:
it is passed as the trace argument to ms() (see documentation on that function). Default is F.
VALUE:
A list containing components for each of the possible arguments, either the value supplied by the user or the default. Its value is used as the control argument to the lme() function.
SEE ALSO:
lme , lme.formula , lme.lmList .
EXAMPLES: 
# decrease the maximum number iterations in the ms() call and
# request that information on the evolution of the iterations be printed
lme.control(ms.maxiter = 20, verbose = T)