Variable not in model when setting objective

回答済み

Hpone Myat Khine

2021年09月19日 04:40

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So I'm running a model - I successfully solved it using naive approach but I want to try and use a more general model form. However when running it I get the variable not in error for my set objective 

 

#Model set-up

m1 = Model('Nutrition')

#Create Variables

x_1 = m.addVars(N, name = 'fruits')

print(x_1)

#Set objective
m1.setObjective(quicksum(cost[i]*x_1[i] for i in range(N)), GRB.MINIMIZE)

#Add Constraints

m1.addConstrs(matrix_fruits[i,j]*x_1[j] for j in range(N)>= min_nutrition[i] for i in range(M))
m1.addConstrs(matrix_fruits[i,j]*x_1[j] for j in range(N)<= max_nutrition[i] for i in range(M))

# Print optimal solutions and optimal value
print('-------------------------------------')

for v in m.getVars():
print(v.VarName, v.x1)

print('Obj:', m1.objVal)

is the code 

N in this case represents the 5 variables I have 

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• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2025年06月23日 02:47 編集済み

  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 why not try our AI Gurobot?.
• 

  Jaromił Najman

  • Gurobi Staff

  2021年09月20日 08:08

  Hi,

  The line where you add the variable is adding them to a wrong model \(\texttt{m}\) instead of your Nutrition model \(\texttt{m1}\). The addVars line should read

  x_1 = m1.addVars(N, name = 'fruits')

  Best regards,
  Jaromił

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