  We describe the study of thermodynamics of materials using replica-exchange
Wang-Landau (REWL) sampling, a generic framework for massively parallel
implementations of the Wang-Landau Monte Carlo method. To evaluate the
performance and scalability of the method, we investigate the magnetic phase
transition in body-centered cubic (bcc) iron using the classical Heisenberg
model parametrized with first principles calculations. We demonstrate that our
framework leads to a significant speedup without compromising the accuracy and
precision and facilitates the study of much larger systems than is possible
with its serial counterpart.
