How to model this kind of indicator constraint in Gurobipy?

Answered

jiangyuan NTXPPA

• April 09, 2019 06:32

x = binAssign.addVar(vtype=GRB.INTEGER, name='x')
y = binAssign.addVar(vtype=GRB.INTEGER, name='y')
z = binAssign.addVar(vtype=GRB.INTEGER, name='z')
a = 3
Model.addConstr((x >= 5) >> or_(z <= 2, y <= 3))

This code shows some errors for me. How should I write the constraint if I want to add
this kind of indicator constraint?

0

• Official comment

  

  Simranjit Kaur

  Gurobi Staff

  • December 06, 2024 00:59

  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?.
• 

  Daniel Espinoza

  • April 10, 2019 16:16

  Hi,

   

  You would need into basic parts the logic, for example:

  let b1 b2 b3 be binary variables

  m.addConstr((b1 == 1) >> (x>= 5))

  m.addConstr((b1 == 0) >> (x <= 5))

  m.addConstr((b2 == 1) >> (y <= 2))

  m.addConstr((b3 == 1) >> (z <= 3))

  m.addConstr(b1 = or_(b2,b3))

  1
• 

  Daniel Espinoza

  • April 10, 2019 16:18

  Small typo: m.addConstr( b1 == or_(b2,b3))

  1
• 

  jiangyuan NTXPPA

  • April 11, 2019 03:30

  

  

  

  Thank you. This way is available. I am wondering if there are other efficient ways so that I don't need to creat so many variables.

  0

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