Determination of critical points and flow diagrams by Monte Carlo renormalization group methods

A general method for calculating block renormalized coupling constants within the framework of the Monte Carlo renormalization group is presented. The method is applicable for any values of the couplings and in particular for those far from the critical point. A new technique for evaluating separately the derivatives of the block renormalized couplings is also discussed. The utility of these methods is demonstrated on the two-dimensional Ising model, where knowledge of the exact critical point in the multiparameter space of coupling constants results in improved values of the critical exponents.