POTTS MODEL CALCULATION DEVICE

摘要

There is provided a Potts model computing device capable of computing a Potts problem that is a multivalued spin problem. The Potts model computing device includes: an Ising model computing device; a computation result storage and determination unit configured to store a value of a spin of the Ising model obtained in a case where a coupling coefficient is set in the Ising model computing device and to determine whether a computation is finished; and a coupling coefficient overwriting unit configured to update a coupling coefficient generated based on the stored value of the spin to the Ising model computing device. According to a value of a set of spins of the Ising model obtained as a computation result corresponding to a coupling coefficient set for an m-th time in the Ising model computing device, the coupling coefficient overwriting unit generates again a coupling coefficient to be set for an (m+1)-th iterative computation and sets the generated coupling coefficient to the Ising model computing device. In a case where a possible value of a multivalued spin is S_i= 0, 1, 2, ..., M - 1 (M is a natural number) and M ≤ 2Ms, the computation result storage and determination unit determines that a computation is finished in a case where a number of iteration times of setting a coupling coefficient in the coupling coefficient overwriting unit reaches a number of iteration times corresponding to Ms (Ms is a natural number), and computes a value S_iby substituting a value σ_imof a spin obtained as a computation result based on the coupling coefficient set for the m-th time computation into the following formula to compute a problem mapped to the Potts model using the Ising model:Si=∑m=1Ms1+σim2m−2