一：cplex的使用：

1.1 导入cplex.jar,包的地址：https://pan.baidu.com/s/1Q0Bv24EQdelV2rY-IrLoZQ 提取码：xn14

1.2 将cplex1290.dll (地址：https://pan.baidu.com/s/1sQXqYTSJWywwaZt5AHVkZQ 提取码：nm0l)添加到VM option中，这里以IDEA为例，

同样eclipse

**二、求解问题。

一个简单的线性规划问题：**

maxs.t.x1+2×2+3×3

−x1+x2+x3≤20

x1−3×2+x3≤30

0≤x1≤40

java 中的 cplex 代码如下：

import ilog.concert.IloException;

import ilog.concert.IloNumVar;

import ilog.cplex.IloCplex;

public class LP1 {

public static void main(String[] args) {

try {

IloCplex cplex = new IloCplex(); // creat a model

double[] lb = {0.0, 0.0, 0.0};

double[] ub = {40.0, Double.MAX_VALUE, Double.MAX_VALUE};

IloNumVar[] x = cplex.numVarArray(3, lb, ub);

double[] objvals = {1.0, 2.0, 3.0};

cplex.addMaximize(cplex.scalProd(x, objvals));

double[] coeff1 = {-1.0, 1.0, 1.0};

double[] coeff2 = {1.0, -3.0, 1.0};

cplex.addLe(cplex.scalProd(x, coeff1), 20.0);

cplex.addLe(cplex.scalProd(x, coeff2), 30.0);

if (cplex.solve()) {

cplex.output().println("Solution status = " + cplex.getStatus());

cplex.output().println("Solution value = " + cplex.getObjValue());

double[] val = cplex.getValues(x);

for (int j = 0; j < val.length; j++)

cplex.output().println("x" + (j+1) + " = " + val[j]);

}

cplex.end();

} catch (IloException e) {

System.err.println("Concert exception caught: " + e);

}

}

}

输出结果：

Tried aggregator 1 time.

N

o LP presolve or aggregator reductions.

Presolve time = 0.00 sec. (0.00 ticks)

Iteration log . . .

Iteration: 1 Dual infeasibility = 0.000000

Iteration: 2 Dual objective = 202.500000

Solution status = Optimal

Solution value = 202.5

x1 = 40.0

x2 = 17.5

x3 = 42.5

这里注意一下，求的是线性公式的最大值，而在MATLAB中利用x=linprog(f,[],[],Aeq,beq,lb);求解的是最小值(我怎么调试都不一致的原因)，这里的参数就不在赘述了。

还有就是设置cplex API在https://wenku.baidu.com/view/7095dd76777f5acfa1c7aa00b52acfc789eb9fed.html有介绍(虽然是c#的，但是java可以借鉴。