KeyError 0 for summing variables in objective function (Using Python)

回答済み

Quentin De Boever

2021年04月15日 01:20 編集済み

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Hi,

I have the following code:

# Model Name
m = gp.Model("Optimal_Sizing")

# Adding Variables
u1 = m.addVars(choice1,vtype=GRB.BINARY,name="u1") # Category 1 choice (DG)
u2 = m.addVars(choice2,vtype=GRB.BINARY,name="u2") # Category 2 choice (PV)
P1 = m.addVars(choice1,T,lb=0.0,ub=P1_ub,name="P1") # Category 1 power (DG) [kW]
P2 = m.addVars(choice2,T,lb=0.0,ub=solar_ub,name="P2") # Category 2 power (PV) [kW]
m.update() # Lazy update


# Setting Objective Function
obj = quicksum(u1[a]*P1[a][b] for a in range(choice1) for b in range(T))
m.setObjective(obj, GRB.MINIMIZE)

When I run this code, I receive the following error:

<ipython-input-64-05a3aaf97bd9> in <genexpr>(.0)
     79 
     80 # Setting Objective Function
---> 81 obj = sum((u1[j]*P1[j][t]) for j in range(choice1) for t in range(T))
     82 m.setObjective(obj, GRB.MINIMIZE)
     83 

KeyError: 0

Not sure why this is happening. Any help is appreciated!

Thank you in advance!

0

• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2025年06月23日 02:56 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?.
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  Jaromił Najman

  • Gurobi Staff

  2021年04月15日 11:53

  Hi Quentin,

  \(\texttt{P1}\) is a tupledict so it has to be accessed via \(\texttt{P1[a,b]}\).

  Best regards,
  Jaromił

  1
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  Quentin De Boever

  2021年04月15日 14:33

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  Jaromil,

  Thank you! Simple mistake, but I'm still new to Gurobi & Python, so hopefully I'll get better!

  Cheers

  0

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