  Advanced thermostats for molecular dynamics are proposed on the base of the
rigorous Langevin dynamics. Because the latter accounts for the subsystem-bath
interactions in details, the bath anisotropy and nonuniformity are described
via the relevant friction tensor. The developed model reflects properly the
relativistic dynamics of the subsystem evolution as well as the nonlinear
friction, which can occur for fast particles with large momenta at elevated
temperature.
