Error when reading model

Answered

Ties van der Heijden

January 07, 2021 13:26

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Dear all,

I want to read a quadratically constrained, non-convex MINLP model for parameter tuning. When building the model in python (using pyomo), and solving everything goes well. However, when I read the .mps file in the interactive shell I get the following error:

Error: duplicate quadratic elements.

Does anyone know how to resolve this?

Kind regards,

Ties

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  June 23, 2025 03:02 Edited

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
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  Eli Towle

  • Gurobi Staff

  January 08, 2021 02:05 Edited

  Did you write the MPS file using Pyomo's built-in write functionality? An MPS file generated by Pyomo does not necessarily capture the exact model as stored internally by Gurobi, and in some cases may not be compatible with Gurobi.

  To write out the MPS file using Gurobi's own file-writer, you can set the \( \texttt{GURO_PAR_DUMP} \) parameter to 1. E.g., in Pyomo:

  opt.options['GURO_PAR_DUMP'] = 1

  You can read more about this topic in the article How do I write an MPS model file from a third-party API?.

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  Ties van der Heijden

  January 08, 2021 12:42

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  Dear Eli,

  Thank you for your swift and spot-on reply.
  This was indeed the issue, the tuning tool is now running.

  Kind regards,

  Ties

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