PoolSearchMode = 2 return the same solutions

Answered

Israel Beltran

March 16, 2023 21:51

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Hi Devs,

Is there a setting that I could use for me not to get the same solutions when I use PoolSearchMode = 2?

Let say I set:
PoolSolution = 10
PoolSearchMode = 2

When I read the ObjVals from that pool, they are always the same.
How can I get 10 unique solutions?

Related to

• Solution Pools

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:47

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  Mario Ruthmair

  • Gurobi Staff

  March 17, 2023 09:04

  Hi Israel,

  PoolSearchMode=2 with PoolSolutions=10 implies that you get the 10 best solutions. But there could be multiple solutions with the same objective value, just differing in the variable values. I guess if you take a look at the variable values, all those solutions will be different.

  If those solutions differ only in variables that are not relevant to you (e.g., helper variables for modeling the problem), then you could set the variable attribute PoolIgnore for those helper variables. Then, you will obtain solutions that differ in the relevant decision variables.

  Best regards,
  Mario

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