Simulated annealing: Difference between revisions

Revision as of 16:12, 24 April 2019

Revision as of 21:01, 30 April 2019

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===Cooling schedule===

The physical analogy that is used to justify simulated annealing assumes that the cooling rate is low enough for the probability distribution of the current state to be near [[thermodynamic equilibrium]] at all times. Unfortunately, the ''relaxation time''—the time one must wait for the equilibrium to be restored after a change in temperature—strongly depends on the "topography" of the energy function and on the current temperature. In the simulated annealing algorithm, the relaxation time also depends on the candidate generator, in a very complicated way. Note that all these parameters are usually provided as [[procedural parameter|black box functions]] to the simulated annealing algorithm. Therefore, the ideal cooling rate cannot be determined beforehand, and should be empirically adjusted for each problem. [[Adaptive simulated annealing]] algorithmalgorithms address this problem by connecting the cooling schedule to the search progress. Other adaptive approach as Thermodynamic Simulated Annealing<ref>{{cite journal |doi=10.1016/j.physleta.2003.08.070 |title=Placement by thermodynamic simulated annealing |year=2003 |last1=De Vicente |first1=Juan |last2=Lanchares |first2=Juan |last3=Hermida |first3=Román |journal=Physics Letters A |volume=317 |issue=5–6 |pages=415–423|bibcode=2003PhLA..317..415D }}</ref>, automatically adjusts the temperature at each step based on the energy difference between the two states, according to the laws of thermodynamics.

==Restarts==