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

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James Donegan

November 16, 2022 20:55 Edited

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I have followed all existing discussion posts about this but cannot figure out why I am getting this error. See below code snippet from python script:

b = {}
gap = {}
for k in range(start_yr,end_yr):
    for i in multi_df:
        reduction[start_yr,i] = 0
        reduction[k+1,i] = 0
        for j in range(len(multi_df[i]['COMPLIANCE'])):
            for u in multi_df[i]['utilities']:
                reduction[k+1,i] += td_matrix[i,j,k]*multi_df[i]['COMPLIANCE']['CO2 reduction (Tons CO2e)'].iloc[j]*(multi_df[i]['utilities'][u]['tCO2_per_dict'][k]/multi_df[i]['utilities'][u]['tCO2_per_dict'][start_yr])
        multi_df[i]['annual_total2'] = {}
        multi_df[i]['annual_total2'][str(k)] = m.addVar(vtype=gp.GRB.CONTINUOUS, name="x")
        multi_df[i]['annual_total2'][str(k)] = multi_df[i]['annual_total'][str(k)]-sum(reduction[k,i] for k in range(start_yr,k))
        m.addConstr(multi_df[i]['annual_total2'][str(k)], gp.GRB.GREATER_EQUAL,0)
        
        b[k,i] = m.addVar(vtype=gp.GRB.BINARY, name='b')
        gap[k,i] = m.addVar(lb=0,vtype=gp.GRB.CONTINUOUS,name='gap')

        M = 15000
        
        m.addConstr(multi_df[i]['annual_total2'][str(k)] >= multi_df[i]['SQFT']*(em_fac[k]) - M*(1-count_tax[k,i]))
        m.addConstr(multi_df[i]['annual_total2'][str(k)] <= multi_df[i]['SQFT']*(em_fac[k]) + M*count_tax[k,i])

        gap[k,i] = b[k,i]*(multi_df[i]['annual_total2'][str(k)] - multi_df[i]['SQFT']*(em_fac[k]))*cost    
        

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:52

  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.
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  James Donegan

  November 16, 2022 20:54

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  FYI, the GurobiError appears for my first of 2 Big M constraints:

  m.addConstr(multi_df[i]['annual_total2'][str(k)] >= multi_df[i]['SQFT']*(em_fac[k]) - M*(1-count_tax[k,i]))

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  Jonasz Staszek

  • Community Moderator

  November 17, 2022 14:41

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  Dear James,

  could you please post a minimal, reproducible example of the code which throws this error?

  For a general discussion about this error, have a look here.

  Best regards
  Jonasz

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  Jaromił Najman

  • Gurobi Staff

  November 17, 2022 14:42

  Could you please adjust the example such that it is reproducible? There are many definitions missing, e.g., what is multi_df[i]['SQFT'], em_fac[k], count_tax[k,i].

  Moreover, you first set multi_df[i]['annual_total2'][str(k)] to be an optimization variable and then override it by an expression in the next line. I am not sure whether this is on purpose or not.

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