adaptive simulated annealing amorphous solid ant colony optimization atom automatic label placement combinatorial optimization cross-entropy method crystal crystallographic defect global optimization global optimum graph cuts in computer vision graph theory greedy algorithm harmony search heuristic internal energy markov chain metaheuristic metallurgy monte carlo method permutation physical system pixel place and route potential energy procedural parameter quantum annealing reactive search search space stochastic gradient descent stochastic optimization stochastic tunneling tabu search thermodynamic equilibrium