Cuts added via Lazy callback are ignore

回答済み

ShahinG

2024年02月03日 13:40

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Hello

I have a pure binary problem. I solve relaxed problem and separate lazy cuts via callback.

I check every cut is violated by 1.

The control leaves callback, presumably applies them and re enters the callback.

I check the solution in callback, it is the same solution and I need to separate the same cut again.

This repeats 3 times until finally the solution changes suggesting that the cuts have been finally effective

Maybe I am missing something here?

I am in pything interface and have 

model.setParam('LazyConstraints', 1)

Thank you in advance.

Shahin

 

関連

• Lazy Constraints

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• 

  Mario Ruthmair

  • Gurobi Staff

  2024年02月06日 14:38

  Hi,

  It can happen (due to multithreading) that the same solution comes up multiple times since newly added lazy cuts might not be synchronized among the threads yet. You have to make sure that you always add a lazy cut if the solution is infeasible even if you did it already before.
  So what you are seeing is expected behavior.

  Best regards,
  Mario

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