The objective bounds improve slowly!

Nazanin Madani

• June 15, 2020 04:00

Hello,

I have a SOC programming problem, which I try to solve. It takes to much time to find an incumbent objective bound, and when it finds one, it improves slowly. I tried different parameters, but it didn't work.

Could anyone help me with it?

Cheers

Nazanin

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• Official comment

  

  Simranjit Kaur

  Gurobi Staff

  • December 06, 2024 00:45

  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 why not try our AI Gurobot?.
• 

  Ting Liang

  • June 21, 2020 19:51

  

  

  

  Hi, Nazanin,

  excuse me.

  I have encountered the same problem, did you find the reasons and solutions now?

  thanks.

   

  best regards

  Ting, Liang

  0
• 

  Nazanin Madani

  • June 23, 2020 15:25

  

  

  

  Hello Ting,

  I realized that my SOC constraint causes this issue, and makes the problem hard to solve. Besides, I wanted to solve a big problem. When I chose smaller ones, it solves but still takes time. Just make sure to play around with MIPFocus and NodeMethod parameters if you are solving a MIP.

  Cheers

  0
• 

  Ting Liang

  • June 24, 2020 11:07

  

  

  

  Dear Nazanin Madani,

  Thanks for your reply.

  Can I further ask how you deal with your problems, to improve the constraints or improve setting parameters or both?

  By the way, can you expand a bit about the constraints problem, like 'big-M constraints' or too loose constraints or...? 

  As I am now stuck here for several days, having tried checking the model carefully(variables & constraints&objectives) and tuning some parameters, including the ones you mentioned.

  thanks a lot, and looking forward to your reply.

   

  best regards

  Ting, Liang

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