Calculation device, control device, processing system, searching method, and recording medium

A searching method comprising:

• finding a solution while finding a solution candidate for an optimization problem with a constraint condition including a variable;
• in a case where the constraint condition is not satisfied for the found solution candidate, changing a value of the variable related to the constraint condition stricter than a predetermined constraint condition to a possible value of a random variable or changing the value of the variable related to the constraint condition to any one of possible values of the variable included in a second region that does not share a common region with a first region including the value of the variable related to the constraint condition from a value of the first region;
• and
• finding a solution candidate again after the value of the variable is changed.

A non-transitory recording medium storing a program for causing a computer to:

• find a solution while finding a solution candidate for an optimization problem with a constraint condition including a variable;
• in a case where the constraint condition is not satisfied for the found solution candidate, change a value of the variable related to the constraint condition stricter than a predetermined constraint condition to a possible value of a random variable or change the value of the variable related to the constraint condition to any one of possible values of the variable included in a second region that does not share a common region with a first region including the value of the variable related to the constraint condition from a value of the first region;
• and
• find a solution candidate again after the value of the variable is changed.