Set definition

Awaiting user input

Shuk Man Chan

• December 25, 2021 11:21

I'm pretty new at Gurobi and am having trouble defining a set below:

$T_{pt}$ = \{ ($\tau,q$) $\in $ {$ES_p$,...,$LS_p$} x {$1$,...,$d_p$}|$\tau$ + $q$ - $1$ = $t$\}

(Not sure if the Markdown can be shown properly). But basically, I need to create a list (T_pt) of set (tau, q) that are in the subset of cartesian products of {ES_p...LSp} x {1...d_p} such that condition (tau + q -1 = t) is fulfiled. 

I managed to create cartesian_list = list(itertools.product({ES_p...LSp},{1...d_p}) but I'm not sure how to create the (tau,q) and link it to the condition.

 

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  Mario Ruthmair

  Gurobi Staff

  • December 28, 2021 12:57

  Hi Shuk,

  How is this related to Gurobi? Are you trying to create variables for each tuple (tau,q)?

  Creating the list of feasible tuples can be done, e.g., with Python generator expressions:

  Tpt = [(tau, q) for tau in range(ESp, LSp + 1) for q in range(1, dp + 1) if tau + q - 1 == t]

  Then, you could for example create one binary variable for each pair (tau,q) by:

  x = model.addVars(Tpt, vtype=GRB.BINARY, name="x")

  Is this what you need?

  Best regards,
  Mario

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