Gurobi for Python Declaring Variables Using Distinct Indices

Answered

Nic Woyak

• September 25, 2019 21:21

Suppose I have some binary variable X indexed by set S twice over where properly speaking X should only be indexed by distinct pairs. 

I am familiar with AMPL where this declaration would be be:

var X{s in S, ss in S: s<>ss} binary;

I want to duplicate the bold part of the above declaration in my Python declaration below, so I would have to add on to or modify it in some way:

X = m.addVars(S, S, vtype=GRB.BINARY)

How do I do this?

0

• 

  Greg Glockner

  Gurobi Staff

  • September 26, 2019 00:10

  Try creating the index as a generator expression:

  X = m.addVars(((s, ss) for s in S for ss in S if s != ss), vtype=GRB.BINARY)

   

  1

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