  We recently introduced a novel replica-exchange scheme in which an individual
replica can sample from states encountered by other replicas at any previous
time by way of a global configuration database, enabling the fast propagation
of relevant states through the whole ensemble of replicas. This mechanism
depends on the knowledge of global thermodynamic functions which are measured
during the simulation and not coupled to the heat bath temperatures driving the
individual simulations. Therefore, this setup also allows for a continuous
adaptation of the temperature set. In this paper, we will review the new scheme
and demonstrate its capability. The method is particularly useful for the fast
and reliable estimation of the microcanonical temperature T(U) or,
equivalently, of the density of states g(U) over a wide range of energies.
