A computer-implemented method for solving a constraint satisfaction
problem (CSP), which is defined by variables and constraints applicable
to the variables, and which has states corresponding to respective sets
of values of the variables. The method includes assigning cost functions
to the constraints so that the states have respective costs determined by
application of the cost functions to the respective sets of values of the
variables, the respective costs defining a problem topography of the CSP
having global extrema corresponding to solutions of the CSP. The
constraints of the CSP are reformulated so as to perform at least one of
increasing a density of the solutions in the problem topography and
smoothing a gradient of the problem topography. One or more of the
solutions of the CSP are found by applying a stochastic CSP solver to the
reformulated constraints.