3.2 代码示例
package javaCplex; import ilog.concert.*; import ilog.cplex.*; public class jCplex { public static void main(String[] args) { // TODO Auto-generated method stub double[] lb = { 0.0, 0.0, 0.0}; double[] ub = { 40.0, Double.MAX_VALUE, Double.MAX_VALUE}; try { IloCplex cplex = new IloCplex(); IloNumVar[] x = cplex.numVarArray(3, lb, ub); double[] objvals = { 1.0, 2.0, 3.0 }; cplex.addMaximize(cplex.scalProd(x, objvals)); cplex.addLe(cplex.sum(cplex.prod(-1.0, x[0]), cplex.prod(1.0, x[1]), cplex.prod(1.0, x[2])), 20); cplex.addLe(cplex.sum(cplex.prod(1.0, x[0]), cplex.prod(-3.0, x[1]), cplex.prod(1.0, x[2])), 30); if (cplex.solve()) { cplex.output().println("Solution status = " + cplex.getStatus()); cplex.output().println("Solution value = " + cplex.getObjValue()); double[] val = cplex.getValues(x); int ncols = cplex.getNcols(); for (int j = 0; j < ncols; ++j) cplex.output().println("Column: " + j + " Value = " + val[j]); } cplex.end(); } catch (IloException e) { System.err.println("Concert exception '" + e + "' caught"); } } }
3.3 注意事项
如果java64位Cplex是32位时，会报错误
java.lang.UnsatisfiedLinkError: ....\cplex\bin\x86_win32\cplex1261.dll: Can't load IA 32-bit .dll on a AMD 64-bit platform java.library.path must point to the directory containing the CPLEX shared library try invoking java with java -Djava.library.path=... Exception in thread "main" java.lang.UnsatisfiedLinkError: ilog.cplex.Cplex.CPXopenCPLEX([I)J at ilog.cplex.Cplex.CPXopenCPLEX(Native Method) at ilog.cplex.CplexI.init(CplexI.java:6608) at ilog.cplex.CplexI.<init>(CplexI.java:629) at ilog.cplex.IloCplex.<init>(IloCplex.java:10194) at ilog.cplex.IloCplex.<init>(IloCplex.java:10209) at javaCplex.jCplex.main(jCplex.java:12)
4 Matlab调用Cplex的配置与示例
4.1 配置
4.1.1 设置路径
注意保持Matlab与Cpex的位数一致性，会报类似【未定义函数或变量 'cplexlink1261']的错误
32位的配置：
64位同上
使用help函数验证是否配置成功
4.1.2 下载yalmip及配置
- yalmip的最新下载网址
- 下载解压将其复制到Matlab安装目录的toolbox路径下
- 设置路径
配置完后，关闭并重启Matlab，测试：
1. >> which issymmetric 2. >> which ishemitian 3. >> which issymmetric
4.2 算例编写
% 清除工作区 clear;clc;close all; % 创建决策变量 x = sdpvar(1,3); %创建约束 C = [ -x(1) + x(2) + x(3) <= 20 x(1) - 3 * x(2) + x(3) <= 30 0 <= x(1) <= 40 ]; % 配置 ops = sdpsettings('verbose',0); % 目标函数 z = -(x(1) + 2 * x(2) + 3 * x(3)); % 注意这是求解最大值，默认是求最小值，所以要加上负号 % 求解 reuslt = optimize(C,z); if reuslt.problem == 0 % problem =0 代表求解成功 value(x) -value(z) % 反转 else disp('求解出错'); end
4.3 算例结果演示
5 python配置Cplex
5.1 配置
这个比较简单，直接找到安装目录下的cplex\python\2.7\x86_win32下找到Cplex文件夹，将其赋值到python27的安装目录下的Lib\site-packages下，打开python控制台，输入如下代码：
import cplex help(cplex)
如果可以看到帮助文档则说明配置成功，
此外本人还做了python37的测试，发现32位的Cplex不能在64位的python37上匹配成功
5.2 编码示例
# -*- coding: utf-8 -*- import cplex from cplex.exceptions import CplexError # data common to all populateby functions my_obj = [1.0, 2.0, 3.0] my_ub = [40.0, cplex.infinity, cplex.infinity] my_lb = [0.0, 0.0, 0.0] my_ctype = "CCC" my_colnames = ["x1", "x2", "x3"] my_rhs = [20.0, 30.0] my_rownames = ["r1", "r2"] my_sense = "LL" def populatebyrow(prob): prob.objective.set_sense(prob.objective.sense.maximize) prob.variables.add(obj=my_obj, lb=my_lb, ub=my_ub, types=my_ctype, names=my_colnames) rows = [[["x1", "x2", "x3"], [-1.0, 1.0, 1.0]], [["x1", "x2", "x3"], [1.0, -3.0, 1.0]] ] prob.linear_constraints.add(lin_expr=rows, senses=my_sense, rhs=my_rhs, names=my_rownames) try: my_prob = cplex.Cplex() handle = populatebyrow(my_prob) my_prob.solve() except CplexError as exc: print(exc) print() # solution.get_status() returns an integer code print("Solution status = ", my_prob.solution.get_status(), ":") # the following line prints the corresponding string print(my_prob.solution.status[my_prob.solution.get_status()]) print("Solution value = ", my_prob.solution.get_objective_value()) numcols = my_prob.variables.get_num() numrows = my_prob.linear_constraints.get_num() slack = my_prob.solution.get_linear_slacks() x = my_prob.solution.get_values() print('x: ') print(x)
5.3 结果演示
6 总结
- 对于C++和C#，都是在VS环境下进行的开发，不存在32位和64位的兼容问题
- java和Matlab以及Python37建议使用64位的Cpex版本
- Matlab在效率上还是比较低的
