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Different upper bound and lower bound for a list of variables

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  • Official comment
    Simranjit Kaur
    • Gurobi Staff Gurobi Staff
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  • Ruoyun Chen
    • Gurobi-versary
    • First Comment
    • First Question

    I guess a more easier way is to change the upper bound and lower bound for the existing variables. How should I do that?

    0
  • Jaromił Najman
    • Gurobi Staff Gurobi Staff

    Hi Ruoyun,

    You can use variable attributes to set the lower and upper bounds after you added the variables to your model.

    An example would be

    import gurobipy 
    from gurobipy import *

    m = Model('test')
    Candidate = [(1,1), (1,2), (1,3), (2,1), (2,2), (2,3)]
    load = m.addVars(Candidate, name="load")

    for c in Candidate:
    if c[0] > 1: # if first number of the tuple is > 1
    load[c].lb = -2 # some lower bound
    if c[1] < 2: # if second number of the tuple is <2
    load[c].ub = 3 # some upper bound

    m.write("myLP.lp") # write LP file to check whether it worked

    Best regards,
    Jaromił

    2

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