OPTIMIZATION APPARATUS AND CONTROL METHOD THEREOF

A first evaluation function calculation unit and a second evaluation function calculation unit calculate a cost function term Ei and a penalty function term Pi in an evaluation function, respectively. A transition control unit stochastically determines whether to accept any of state transitions, based on a product of a ratio between an inverse temperature βi and a penalty factor αi and Pi and Ei. An exchange control unit supplies βi and αi to each annealing unit, βi and αi having been set such that each annealing unit has a different ratio between βi and αi, receives Ei and Pi from each annealing unit, and exchanges βi between first and second annealing units among the plurality of annealing units and αi between the first and second annealing units, in accordance with a probability based on βi, αi, Ei, and Pi of the first and second annealing units.