Error raised when solving standard Benders decomposition with 'xpress' solver

[Senam Sedzro]

Hi All,

I encountered the following error while solving the standard Benders decomposition example found at https://github.com/Pyomo/pyomo/blob/master/examples/pyomo/benders/runbenders

##################################################################################

runfile('C:/Users/kseo/Documents/Python Scripts/BendersPy/runbenders.py', wdir='C:/Users/kseo/Documents/Python Scripts/BendersPy')

Iteration= 1
Profit for scenario=Base Sub-Problem is 179523.0

Profit for scenario=Low Sub-Problem is 125839.0

Profit for scenario=High Sub-Problem is 93830.0

Traceback (most recent call last):

File "", line 1, in
runfile('C:/Users/kseo/Documents/Python Scripts/BendersPy/runbenders.py', wdir='C:/Users/kseo/Documents/Python Scripts/BendersPy')

File "C:\Users\kseo\AppData\Local\Continuum\anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 705, in runfile
execfile(filename, namespace)

File "C:\Users\kseo\AppData\Local\Continuum\anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 102, in execfile
exec(compile(f.read(), filename, 'exec'), namespace)

File "C:/Users/kseo/Documents/Python Scripts/BendersPy/runbenders.py", line 74, in
inst.urc[inst.Sell[p,t]]

File "C:\Users\kseo\AppData\Local\Continuum\anaconda3\lib\site-packages\pyomo\core\kernel\component_map.py", line 100, in getitem
% (id(obj), str(obj)))

KeyError: "Component with id '2149761530272': Sell[coils,2]"

##################################################################################

Has anyone experienced a similar issue?

Thank you.

Senam

[Gabriel Hackebeil]

I can’t reproduce that error. What version of Pyomo are you using? Also, do you have CPLEX installed? I believe that example requires it.

You might try adding "tee=True” to the solve_all_instances call in that example to see if some error is occurring. It looks like the urc solution suffix is not being returned from the solver.

Gabe

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[Senam Sedzro]

Thank you, Gabe.

I don't have CPLEX installed.