  We present the speedup from a novel parallel implementation of the
multicanonical method on the example of a lattice gas in two and three
dimensions. In this approach, all cores perform independent equilibrium runs
with identical weights, collecting their sampled histograms after each
iteration in order to estimate consecutive weights. The weights are then
redistributed to all cores. These steps are repeated until the weights are
converged. This procedure benefits from a minimum of communication while
distributing the necessary amount of statistics efficiently.
  Using this method allows us to study a broad temperature range for a variety
of large and complex systems. Here, a gas is modeled as particles on the
lattice, which interact only with their nearest neighbors. For a fixed density
this model is equivalent to the Ising model with fixed magnetization. We
compare our results to an analytic prediction for equilibrium droplet
formation, confirming that a single macroscopic droplet forms only above a
critical density.
