Symmetry parameter options do not cause any changes

ユーザーの入力を待っています。

Iria Rodríguez Acevedo

2022年06月13日 12:10

• 
• 

Good afternoon, 

I've been working with the football pool problem, which is a problem that presents symmetry.

Using the different options of the symmetry parameter that Gurobi has, I have found that these do not cause any change. That is, the same number of nodes are explored with all the options and the execution times are similar, regardless of how aggresive we are with symmetry detection.

I don't understand the reason of this behavior, as I was expecting that detecting symmetries would improve the performance of the branch and bound algorithm.

Given the posibility that this behavior only occurred with the football pool problem, I have also verified what happens with the graph coloring problem, which is a problem that presents symmetry too. 

The results obteined with different instances used are again analogous to those obteined with the football pool problem.

I attach two tables with the results for two of the instances:

 

Could someone tell me why this happens?

0

• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2025年11月16日 23:34

  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 try Gurobot, our chatbot interface offering instant, expert-level support.
• 

  Jaromił Najman

  • Gurobi Staff

  2022年06月15日 13:21

  Hi Iria,

  This sounds interesting and I would like to investigate further.

  Could you please share the graph coloring models and the symmetry breaking constraints that are necessary for this performance improvement? Uploading files in the Community is not possible but we discuss an alternative in Posting to the Community Forum.

  Best regards, 
  Jaromił

  0

投稿コメントは受け付けていません。