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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  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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