add constraints in callback

Answered

peilin chan

April 30, 2024 07:47

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Hi,

I want to add some constraints in callback. When a better incumbent is found, that means some variable can be excluded(set to 0) because they can not be included in a better solution. How can i do?

Looking forward to any advices.

Thanks 

Related to

• Callbacks
• User Cuts

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:25

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  David Torres Sanchez

  • Gurobi Staff

  April 30, 2024 09:22

  Hi Peilin,

  You can add some lazy cuts to achieve this.
  See our TSP example:

  • modeling-examples/traveling_salesman/tsp.ipynb at master · Gurobi/modeling-examples
  • or, tsp.py

  Cheers, 
  David

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  peilin chan

  April 30, 2024 09:35 Edited

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  Hi David,

  Thanks for your advices.

  Does lazy cuts be considered in the following solve? The cuts I want to add is to exclude some unpromising feasible solutions, which is different from that in TSP model to exclude infeasible solutions.

  Best regards,

  Peilin

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  David Torres Sanchez

  • Gurobi Staff

  April 30, 2024 10:04

  Hi Peilin,

  In that case you can use user cuts (instead of lazy cuts), however these will not remain for the next solve.
  One way to keep these would be to save them in a separate container and add them all after the solve.

  Cheers, 
  David

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  peilin chan

  April 30, 2024 11:53

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  Get it. Thank you David

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