说明：  规划中的变量（部分或全部）限制为整数时，称为整数规划。若在线性规划模型中， 变量限制为整数，则称为整数线性规划。目前所流行的求解整数规划的方法，往往只适 用于整数线性规划。
(When variables (partial or all) in planning are restricted to integers, they are called integer programming. In linear programming models, variables are restricted to integers, which are called integer linear programming. The popular methods for integer programming are often applied to integer linear programming.)