As of this time, the suite of optimization methods include: exhaustive, local search (steepest descent and tabu), sides (not a general method), strict-finger/constrained (likely will be deprecated), nearest (projection to satisfy the given constraints, under consideration to be moved into a separate function out of optimize.py), and shuffle (not part of optimize.py but it is under consideration to be moved as part of it).
Simulated annealing is a common non-linear optimization method. This feature request suggests implementation of this method for layout design.