GurobiError: Constraint has no bool value (are you trying "lb <= expr <= ub"?)

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Dongjun Cai

November 07, 2022 08:29

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Hi, 

Recently, i had this issue when i added a constraints statement :

~\AppData\Local\Temp/ipykernel_18284/4133350432.py in <module>
     34 m.addConstrs((T5[i] + Px <= T2[j] + (1-s[i,j,g])*M for i in U for j in L for g in G), name="Neighboring AGV for the same buffering area 4")
     35 #First tasks for AGVs
---> 36 m.addConstrs((T0 + Dis_Mat[(b, g)]/v1  <= T2[i] + (2 - x['dummy_a', i, n]- w[i,g,n])*M for i in L for n in N for b in B for g in G), name="First tasks for AGVs 1")

GurobiError: Constraint has no bool value (are you trying "lb <= expr <= ub"?)

 

Here is my constraint statement:

Decision variables:

T2[i], x['dummy_a', i, n],  w[i,g,n]

T0 is constant.

m.addConstrs((T0 + Dis_Mat[('Depot', g)]/v1  <= T2[i] + (2 - x['dummy_a', i, n]- w[i,g,n])*M for i in L for n in N for g in G), name="First tasks")

I checked from gurobi existing answers, it says that the error indicates a double side constrains is unsupported in the new version. 

This does not  apply to this case, the added constraint is not double side.

I hope to know what could be the causes and possible solutions for the error.  (The code is in python in Jupyter notebook)

Thanks

 

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 16, 2025 23:25

  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.
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  Jaromił Najman

  • Gurobi Staff

  November 07, 2022 11:40

  Hi,

  Could you please provide a full minimal working example to reproduce the issue?

  In particular, it is not clear what \(\texttt{Dis_Mat,v1,M}\) are.

  Best regards, 
  Jaromił

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