1. An information processing apparatus for calculating a ground state which is a spin alignment with minimum energy of an original problem that is an Ising model, or an approximate solution of the ground state as a solution of the original problem, the information processing apparatus comprising a hardware processor coupled to a memory and a network interface card (NIC), the hardware processor configured to: generate one or more sub-problems, which are Ising models, from the original problem; control an Ising chip controller which controls one or more Ising chips each of which is a dedicated hardware, the one or more Ising chips configured to search for a ground state of a problem of an Ising model having specified multiple types of coefficient values and search for a ground state of each of the sub-problems; and generate the solution of the original problem based on a solution of each sub-problem obtained by the search made by the one or more Ising chips; wherein the hardware processor is configured to generate the sub-problems which are the Ising models having one or more coefficient values selected from the multiple types based on one or more coefficient values of the Ising model of the original problem, and wherein the generating the one or more sub-problems further comprising the hardware processor configured to: normalize each of the coefficient values of the Ising model of the original problem within a specified range; generate a random number within the specified range; compare each of the normalized coefficient values of the Ising model of the original problem with the random number; and determine a coefficient value selected from the multiple types based on a comparison result as a coefficient value of the Ising model of the sub-problem corresponding to each of the normalized coefficient values.