Add Constraint for only some tuples

Answered

Ozlem Akbudak

• March 20, 2021 08:25

Hello,

I wrote the constraint below.

I expect it to add a constraint for only (3, 1), (4, 2), (5, 2), (5, 3) these tuples.

But instead, it adds the same constraint for whole taskFS tuple list.

How can I fix this problem?

Thanks,

Ozlem

setLag = (3,4,5)

taskFS = gp.tuplelist([(2, 1),
                       (3, 1),
                       (4, 2),
                       (5, 2), (5, 3),
                       (6, 3),
                       (7, 5),
                       (8, 5), (8, 6),
                       (9, 6),
                       (10, 7), (10, 8), (10, 9),
                       (12, 10), (12, 11)])

startTimeFSLag = m.addConstrs((s[t] >= c[j] + lag[t] for t in setLag for (t, j) in taskFS), name="startTimeFSLag")

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• Official comment

  

  Simranjit Kaur

  Gurobi Staff

  • December 06, 2024 00:34

  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?.
• 

  Matthias Miltenberger

  Gurobi Staff

  • March 22, 2021 16:14
  • Edited

  Hi Ozlem,

  To implement this restriction, you can just put an if-condition into the list comprehension:

  only = [(3, 1), (4, 2), (5, 2), (5, 3)]
  startTimeFSLag = m.addConstrs(
      (s[t] >= c[j] + lag[t] for t in setLag for (t, j) in taskFS if (t, j) in only),
      name="startTimeFSLag",
  )

  Cheers,
  Matthias

  0

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