python - PuLP 中的线性整数优化

Question

在开始一个更大的问题之前，我试图做以下简单的示例优化问题。代码:

from pulp import *
x = LpVariable("x", 0, 3)
y = LpVariable("y", 0, 1)
prob = LpProblem("myProblem", LpMinimize)

prob += x + y <= 2
#objective function
prob += -4*x + y

status = prob.solve(GLPK(msg = 0))
#results
value(x)

我收到以下错误:

Traceback (most recent call last):
  File "C:\Users\mahabubalam\Desktop\Works\GUI\whiskas.py", line 85, in <module>
    status = prob.solve(GLPK(msg = 0))
  File "C:\Python34\lib\site-packages\pulp-1.5.6-py3.4.egg\pulp\pulp.py", line 1619, in solve
    status = solver.actualSolve(self, **kwargs)
  File "C:\Python34\lib\site-packages\pulp-1.5.6-py3.4.egg\pulp\solvers.py", line 335, in actualSolve
    raise PulpSolverError("PuLP: cannot execute "+self.path)
pulp.solvers.PulpSolverError: PuLP: cannot execute glpsol.exe

谁能帮我理解这是为什么？

Answer 1

执行以下两个步骤后，我已成功运行您的代码:

1. 从

   下载GLPK

   http://sourceforge.net/projects/winglpk/files/latest/download (正如 oyvind 所提到的)

2. 将其解压缩到(例如): C:\glpk_is_here\

3. 在运行 python 之前将 GLPK 二进制文件添加到您的系统路径 C:\><b>set PATH=%PATH%;C:\glpk_is_here\glpk-4.55\w64</b>


4. 使用与 (3) 相同的 cmd 窗口，使用 python/ipython 运行您的代码:
   C:\><b>ipython your_code.py</b>


5. 查看结果 Out[4]: 2.0

祝你好运。