How can I add a parameter into the the constraint?

Answered

merve özer

• January 25, 2021 18:50
• Edited

I am trying to solve the following generalized assignment problem in Gurobi. I managed to solve the problem when bij is =1 which is a simple assignment problem. Now I am trying to solve the generalized assignment problem when bij (capacity consumption values) has different values, but I got stuck in adding this bij parameter into the constraints. I think, I should firstly define bij (but not quite sure how to), then put into the Resource1 and Resource2 constraints, something like that,  but it did not work. 

Resource1 = m.addConstrs((x.sum('Resource1', '*')*b(i,j) for i in I for j in J<=5 ), 'Resource1')

 

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• 

  Jaromił Najman

  Gurobi Staff

  • January 26, 2021 13:58
  • Edited

  Hi Merve,

  You could use the quicksum function to model these 2 constraints as

  Resource1 = m.addConstr( quicksum( x['Resource1',i] * mh['Resource1',i] for i in I ) <= 5 , name="Resource1" )
  Resource2 = m.addConstr( quicksum( x['Resource2',i] * mh['Resource2',i] for i in I ) <= 12 , name="Resource2" )

  You can access the values of \(\texttt{mh}\) via the \(\texttt{[]}\) operator and the corresponding key given in the \(\texttt{matching}\) list. Thus, \(\texttt{mh['Resource1‘,'item1‘]}\) provides the integer 3.

  Best regards,
  Jaromił

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• 

  merve özer

  • January 26, 2021 15:57

  

  

  

  This is great! I obtained exactly what I wanted. Thank you very much.

  Kind regards,

  Merve

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