  We propose improvements in numerical evaluation of symmetric stable density
and its partial derivatives with respect to the parameters. They are useful for
more reliable evaluation of maximum likelihood estimator and its standard
error. Numerical values of the Fisher information matrix of symmetric stable
distributions are also given. Our improvements consist of modification of the
method of Nolan (1997) for the boundary cases, i.e., in the tail and mode of
the densities and in the neighborhood of the Cauchy and the normal
distributions.
