An Importance Sampling Algorithm for the Ising Model with Strong   Couplings
  We consider the problem of estimating the partition function of the ferromagnetic Ising model in a consistent external magnetic field. The estimation is done via importance sampling in the dual of the Forney factor graph representing the model. Emphasis is on models at low temperature (corresponding to models with strong couplings) and on models with a mixture of strong and weak coupling parameters. 
Mehdi Molkaraie
stat.CO cs.IT math.IT physics.comp-ph