[DO NOT MERGE] Investigate issue with GLPK solver on LP files generated by PyPSA

[jacek-oet]

PyPSA Version Testing

I generated LP files by running:

python pypsa-gas+wind+sol+ely-ucgas-1-1h.py

Tested PyPSA Versions

Tested versions (PyPSA release history: https://pypi.org/project/pypsa/#history):

• 0.30.1
• 0.30.2
• 0.30.3
• 0.31.0
• 0.31.1

Results with pypsa-gas+wind+sol+ely-ucgas-1-1h.py

Benchmark,Solver,Status,Termination Condition,Objective Value,Runtime (s),Memory Usage (MB)
pypsa-gas+wind+sol+ely-ucgas-1-1h_0.30.1,glpk,ok,optimal,84667526620.0,206.10014152526855,281.316
pypsa-gas+wind+sol+ely-ucgas-1-1h_0.30.2,glpk,ok,optimal,84667526620.0,200.6377453804016,280.896
pypsa-gas+wind+sol+ely-ucgas-1-1h_0.30.3,glpk,ok,optimal,84667526620.0,199.55054306983948,281.024
pypsa-gas+wind+sol+ely-ucgas-1-1h_0.31.0,glpk,warning,unknown,nan,0.5099265575408936,169.208
pypsa-gas+wind+sol+ely-ucgas-1-1h_0.31.1,glpk,warning,unknown,nan,0.4162724018096924,167.44

Additional Test with pypsa-gas+wind+sol+ely-1-1h.py

To further investigate, I also tested the file pypsa-gas+wind+sol+ely-1-1h.py with PyPSA versions:

• 0.30.3
• 0.31.0

Results with pypsa-gas+wind+sol+ely-1-1h.py

Benchmark,Solver,Status,Termination Condition,Objective Value,Runtime (s),Memory Usage (MB)
pypsa-gas+wind+sol+ely-1-1h_0.30.3,glpk,ok,optimal,31714138110.0,103.1927318572998,274.024
pypsa-gas+wind+sol+ely-1-1h_0.31.0,glpk,warning,unknown,nan,0.3610563278198242,165.244

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Summary

Using PyPSA version 0.31.* appears to introduce an issue, resulting in a warning status and an unknown termination condition with NaN as the objective value. This issue does not occur with earlier versions (0.30.*), where the files are processed successfully without any errors.

In summary:

• PyPSA 0.30.* versions work as expected, producing ok status and optimal results.
• PyPSA 0.31.* versions cause an error with <= +inf in LP files, leading to warning and unknown conditions when solved by GLPK.

glpsol --lp runner/benchmarks/pypsa-gas+wind+sol+ely-1-1h_0.31.0.lp 
GLPSOL--GLPK LP/MIP Solver 5.0
Parameter(s) specified in the command line:
 --lp runner/benchmarks/pypsa-gas+wind+sol+ely-1-1h_0.31.0.lp
Reading problem data from 'runner/benchmarks/pypsa-gas+wind+sol+ely-1-1h_0.31.0.lp'...
runner/benchmarks/pypsa-gas+wind+sol+ely-1-1h_0.31.0.lp:731757: missing right-hand side
CPLEX LP file processing error

[siddharth-krishna]

Thanks Jacek! Closing this because of the temporary fix in #51