We propose two efficient algorithms for configurational sampling of systems with rough
energy landscape. The first one is a new method for the determination of the multicanonical
weight factor. In this method, a short replica-exchange simulation is performed and the
multicanonical weight factor is obtained by the multiple histogram reweighting techniques.
The second one is a further extension of the first in which a replica-exchange multicanonical
simulation is performed with a small number of replicas. These new algorithms are …