Skip to main content

MIPSOL Callback

Answered
Sayed Hamid Hosseini Dolatabadi
  • Gurobi-versary
  • First Question
  • First Comment

I am implementing MIPSOL Callback in Python to add lazy cuts for the subtour elimination and also some other infeasibility checks which are global constraints of the problem. However, I was wondering whether the MIPSOL Callback function add lazy cuts locally to that specific node or add them to the entire tree?

Related to

0

Comments

4 comments

Date Votes
  • Official comment
    Juan Orozco
    • Gurobi Staff

    Please note that there's no such thing defined by Gurobi as Lazy Cuts. You may be referring to either Lazy Constraints or User Cuts. In the light of this, I suggest to read through our article What Is the Difference between User Cuts and Lazy Constraints?

    In any case, to answer your question: both are enforced globally.

  • Sayed Hamid Hosseini Dolatabadi
    • Gurobi-versary
    • First Question
    • First Comment

    Thanks for your response. Yes, it was my typo and I am referring to Lazy Constraints. So, if inside the callback, a sequence is detected as infeasible and the corresponding constraint for preventing that sequence from happening is added, that sequence should not be appeared in the solution of any other integer nodes, correct?

    0
  • Juan Orozco
    • Gurobi Staff

    Indeed. Subsequent feasible solutions must abide by the newly added lazy constraint.

    0
  • Sayed Hamid Hosseini Dolatabadi
    • Gurobi-versary
    • First Question
    • First Comment

    Thanks a lot.

    0

Please sign in to leave a comment.

Didn't find what you were looking for?

New post