Multicanonical sampling of Rosenbluth-weighted chains

Monte Carlo and chain growth methods for molecular simulations 

Before we go into the technical aspects of this method, let us first discuss it more formally, The energy-dependent multicanonical weights (4,153) are trivially introduced into the partition sum as suitable decomposition of unity in the following way  

Since multicanonical sampling effectively works at infinite canonical temperature, we use (4,153) to express the partition sum that then coincides with the total number of all possible conformations as 

Taking this as the probability for generating chains of length n,p W , leads to the desired flat distribution H E), from which the density of states is obtained by 

The canonical distribution at any temperature T is calculated by simply reweighting the 

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