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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  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

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  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

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  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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