A new paradigm for petascale Monte Carlo simulation: Replica exchange   Wang-Landau sampling
  We introduce a generic, parallel Wang-Landau method that is naturally suited to implementation on massively parallel, petaflop supercomputers. The approach introduces a replica-exchange framework in which densities of states for overlapping sub-windows in energy space are determined iteratively by traditional Wang-Landau sampling. The advantages and general applicability of the method are demonstrated for several distinct systems that possess discrete or continuous degrees of freedom, including those with complex free energy landscapes and topological constraints. 
Ying Wai Li, Thomas Vogel, Thomas W\"ust, and David P. Landau
physics.comp-ph cond-mat.soft