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

Answered

Yunus Emre Çakır

January 26, 2024 10:32

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I have the following decision variables
r_max = bilevel.addVar(lb= 0 , ub= gp.GRB.INFINITY, vtype=gp.GRB.CONTINUOUS, name="r_max")

 

x_ij_km = {}
for i, j in edges:
    for k in K:
        for m in M:
            x_ij_km[i, j, k, m] = bilevel.addVar(lb=0, ub=gp.GRB.INFINITY, vtype=gp.GRB.CONTINUOUS, name=f"x_{i}_{j}_{k}_{m}")

When I run the following constraint (
bilevel.addConstrs(sum(x_ij_km[i, j, k, m] * l_ij_mk_c[i, j, k, m, c] * l_ij_mk_c * phi_k[k] for k in K for m in M for i,j in edges) <= r_max for c in C) 

Note: l_ij_mk_c, l_ij_mk_c, phi_k are all parameters 
I receive the following error:

    bilevel.addConstrs(sum(x_ij_km[i, j, k, m] * l_ij_mk_c[i, j, k, m, c] * sigma_ij_km[i, j, k, m] * phi_k[k] for k in K for m in M for i,j in edges) <= r_max for c in C)

  File src/gurobipy/tempconstr.pxi:57 in gurobipy.TempConstr.__bool__

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

What might be the reason? How can I fix that?

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:31

  This post is more than two 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.
• 

  Marika Karbstein

  • Gurobi Staff

  January 26, 2024 10:44

  Please check the article Constraint has no bool value (are you trying "lb <= expr <= ub"?)  for a solution.

  If you do not find any, then please create a minimum reproducible example (Tutorial: Preparing a Minimal Reproducible Example).

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