  With the guidance offered by nonequilibrium statistical thermodynamics,
simulation techniques are elevated from brute-force computer experiments to
systematic tools for extracting complete, redundancy-free and consistent coarse
grained information for dynamic systems. We sketch the role and potential of
Monte Carlo, molecular dynamics and Brownian dynamics simulations in the
thermodynamic approach to coarse graining. A melt of entangled linear
polyethylene molecules serves us as an illustrative example.
