的Python/Pyomo与GLPK求解 - 错误

Question

我试图运行与Pyomo + GLPK求解（Anaconda2 64 Spyder的）一些笑着例如：

from pyomo.environ import * 
model = ConcreteModel() 
model.x_1 = Var(within=NonNegativeReals) 
model.x_2 = Var(within=NonNegativeReals) 
model.obj = Objective(expr=model.x_1 + 2*model.x_2) 
model.con1 = Constraint(expr=3*model.x_1 + 4*model.x_2 >= 1) 
model.con2 = Constraint(expr=2*model.x_1 + 5*model.x_2 >= 2) 

opt = SolverFactory("glpk") 
instance = model.create() 
#results = opt.solve(instance) 
#results.write() 

，但我得到了以下错误消息：

invalid literal for int() with base 10: 'c' 
Traceback (most recent call last): 

    File "<ipython-input-5-e074641da66d>", line 1, in <module> 
    runfile('D:/..../Exampe.py', wdir='D:.../exercises/pyomo') 

    File "C:\...\Continuum\Anaconda21\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 699, in runfile 
    execfile(filename, namespace) 

    File "C:\....\Continuum\Anaconda21\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 74, in execfile 
    exec(compile(scripttext, filename, 'exec'), glob, loc) 

    File "D:/...pyomo/Exampe.py", line 34, in <module> 
    results = opt.solve(instance) 

    File "C:\....\Continuum\Anaconda21\lib\site-packages\pyomo\opt\base\solvers.py", line 580, in solve 
    result = self._postsolve() 

    File "C:\...Continuum\Anaconda21\lib\site-packages\pyomo\opt\solver\shellcmd.py", line 267, in _postsolve 
    results = self.process_output(self._rc) 

    File "C:\...\Continuum\Anaconda21\lib\site-packages\pyomo\opt\solver\shellcmd.py", line 329, in process_output 
    self.process_soln_file(results) 

    File "C:\....\Continuum\Anaconda21\lib\site-packages\pyomo\solvers\plugins\solvers\GLPK.py", line 454, in process_soln_file 
    raise ValueError(msg) 

ValueError: Error parsing solution data file, line 1 

我从http://winglpk.sourceforge.net/下载了glpk - > unziped +将parth添加到了环境变量“路径”中。

希望有人能帮助我 - 谢谢！

Answer 1

这是GLPK 4.60中的一个已知问题（glpsol改变了打破Pyomo 4.3解析器的输出格式）。您可以下载旧版本的GLPK，或者将Pyomo升级到4.4.1（其中包含更新的解析器）。