Optimization apparatus and control method thereof

A control method of an optimization apparatus, the control method comprising:

• outputting, by a compression unit included in the optimization apparatus, compressed coefficient data in which a coefficient matrix including coupling coefficients, each of which indicates a coupling strength between bits of an Ising model obtained by converting a calculation target problem, is compressed based on a symmetry property or a pattern property of the coefficient matrix;
• holding, by a storage unit included in the optimization apparatus, the compressed coefficient data outputted by the compression unit;
• decoding, by a decoding unit included in the optimization apparatus, the compressed coefficient data stored in the storage unit to obtain the coupling coefficients;
• and
• performing, by an annealing unit included in the optimization apparatus, a simulated annealing operation by using the coupling coefficients obtained by the decoding unit.