random order of the lp file

[arg...@gmail.com]

I have run my model with the same case study in two consecutive runs and the lp file written witth modelname.write( symbolic-solver_labels=True) is not always the same, the terms in the constraints are reordered.

Have anybody have this behavior? Any way to avoid it?

Andrés

[Siirola, John]

Andrés,

 

The Pyomo solver interfaces go to pretty significant lengths to ensure that for deterministic import, the model should be emitted to the solver in a deterministic manner.  There are two things that might be going on:

• You have found a determinism bug in the writer
• You are not generating your model in a deterministic manner.  This is usually the result of iterating over python `set` objects (which are not guaranteed to be deterministic).

 

Unfortunately, there is little more we can tell you unless you can share a (hopefully minimal) example so we can reproduce the behavior you are observing.

 

Best regards,

John

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[Andres Ramos]

Hi John,

Thanks a lot for your answer.

I am using the model openTEPES (https://opentepes.readthedocs.io/en/latest/index.html) that can be installed as a library with

pip install openTEPES

and it will install the model in the site-packages folder. Then run in a python console

openTEPES_Main

When running, the solver to select is whatever you have already installed (openTEPES doesn't install by default any solver) and the test case to select is the 9n, but for making it smaller substitute with the files of the message the corresponding ones downloaded in the 9n folder.

I am annexing also the lp files obtained in two consecutive runs and the gurobi log files.

Regards

Andrés

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De: 'Siirola, John' via Pyomo Forum <pyomo...@googlegroups.com>
Enviado: martes, 17 de septiembre de 2024 19:48
Para: pyomo...@googlegroups.com <pyomo...@googlegroups.com>
Asunto: RE: [EXTERNAL] random order of the lp file

 

To view this discussion on the web visit https://groups.google.com/d/msgid/pyomo-forum/SA9PR09MB482919727F468E98526C9911DA612%40SA9PR09MB4829.namprd09.prod.outlook.com.

[Andres Ramos]

John,

Dheepak Krishnamurthy from EPRI proposes to convert all the pyomo sets we have define as ordered=False to ordered=True and he has tested the change and it works

Andrés

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De: 'Siirola, John' via Pyomo Forum <pyomo...@googlegroups.com>
Enviado: martes, 17 de septiembre de 2024 19:48
Para: pyomo...@googlegroups.com <pyomo...@googlegroups.com>

Asunto: RE: [EXTERNAL] random order of the lp file

 

To view this discussion on the web visit https://groups.google.com/d/msgid/pyomo-forum/SA9PR09MB482919727F468E98526C9911DA612%40SA9PR09MB4829.namprd09.prod.outlook.com.