TypeError: 'gurobipy.LinExpr' object is not iterable

Answered

Çağlar Aydın

October 29, 2022 12:30

mdl.addConstrs(((x[0,2]+x[0,3]) <= (max(x[0,2]+x[0,3]))), name='22')

 

Why is the error occuring?

1

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 16, 2025 23:26

  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 try Gurobot, our chatbot interface offering instant, expert-level support.
• 

  Jaromił Najman

  • Gurobi Staff

  November 02, 2022 09:34

  I am not sure what you are trying to model with your constraint. Currently, your constraint reads

  \[\begin{align*}
  x_{0,2} + x_{0,3} \leq \max(x_{0,2} + x_{0,3})
  \end{align*}\]

  which is redundant. If you are trying to implement

  \[\begin{align*}
  x_{0,2} + x_{0,3} \leq \max(x_{0,2},x_{0,3}, \dots)
  \end{align*}\]

  then you have to us the addGenConstrMax method.

  Note that this method only accepts single variables. It does not accept linear or quadratic expressions. Thus, if you want to take the \(\max\) of a more complex term, you have to introduce auxiliary variables and equality constraints.

  Best regards, 
  Jaromił

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