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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  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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