two side condition with binary

Answered

Haung Carol

September 30, 2023 17:23

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Hi!

I have a binary x_in_grid, which is to decide if my variable X is in the range [0,5]

X is a continuous variable.

So, my constraints is : if 0<=X<=5, then x_in_grid==1

 here is something I'm trying to do, but it doesn't work

 

model.addConstr(X >=0- M * (1 - x_in_grid)) 
model.addConstr(X <= 5+ M * x_in_grid) 

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• 

  Simranjit Kaur

  • Gurobi Staff

  October 01, 2023 23:06

  Hi Haung,

  Assuming X can only take non-negative values, you can model the condition "if 0<=X<=5, then x_in_grid==1" with the following constraints:

  X <= 5 + M*(1-x_in_grid)
  X >= 6*(1-x_in_grid)

  If X <= 5, x_in_grid will have to take value 1, as otherwise, the second constraint above will cause an infeasibility.

  Best regards,
  Simran

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