INFORMATION PROCESSING SYSTEM, INFORMATION PROCESSING METHOD, AND COMPUTER-READABLE RECORDING MEDIUM STORING PROGRAM

An information processing system configured to calculate a combinatorial optimization problem that includes a constraint condition based on an energy function of an Ising model represented by a sum of a cost term and a constraint term that corresponds to the constraint condition, the information processing system including: a processing circuit configured to obtain problem information of the combinatorial optimization problem, calculate, based on the problem information, an expected value of a change amount of the cost term when transition from a solution that satisfies the constraint condition to a solution that does not satisfy the constraint condition occurs, determine a coefficient of the constraint term based on the expected value, and output information of the energy function using the determined coefficient; and a search circuit that searches for a ground state of the Ising model based on the output information.