Information processing device and control method therefor

A method of controlling an information processing apparatus that calculates a certain ground state in a spin arrangement which minimizes energy of a certain problem in an Ising model, or a solution approximate to the ground state, as a solution to the problem, the apparatus including

• a plurality of semiconductor chips, each of which retains a value of one spin or values of a plurality of spins and simulates interactions among the spins,
• inter-chip wiring that connects between each of the necessary semiconductor chips, and
• a processor that controls each of the semiconductor chips and thus causes the each of the semiconductor chips to perform interaction computation, the method comprising:
• a first step of causing the processor to convert data of the problem into data of a lattice-shaped Ising model, which is expressed by the plurality of semiconductor chips, without causing the spin arrangement in the ground state of the Ising model for the problem, to be changed;
• a second step of causing the processor to divide the data of the lattice-shaped Ising model, which results from the conversion, for allocation to each of the plurality of semiconductor chips;
• and
• a third step of causing the processor to cause each of the semiconductor chips to perform the interaction computation,
• wherein in the first step, the processor replaces first spins of the Ising model, which is the problem, with sets of third spins, respectively, of which the number is the same as the number of second spins that exert interactions on the first spins, arranges the sets of third spins in such a manner that the lattice-shaped Ising model as a whole is stepwise, and converts the data of the problem into the data of the lattice-shaped Ising model, and
• wherein in the first step, on the assumption that an interaction coefficient between the i-th second spin and the i-th third spin that corresponds to the second spin is ji, an external magnetic field coefficient in the i-th third spin is ai, an interaction coefficient between the i-th third spin and the (i+1)-th third spin is bi, the number of second spins is n, and an external magnetic field coefficient in the first spin that correspond to the third spin is h0, the processor sets each interaction coefficient and each external magnetic field coefficient of the lattice-shaped Ising model in such a manner that the following equations are satisfied:
• [Equation 9]
• |Ji|+|ai|>|bi| (9)
• and
• [Equation 10]
• a1+a2+ . . . +an=h0 (10)