What means "Warning: 1 variables dropped from basis"

回答済み

Jonathan Ayala Marcelo

2023年07月01日 17:00

• 
• 
• 

Hi!

I would like to know what means the warning "1 variables dropped from basis". I know that is a symptom that my model have numerical issues, but I would like to know what is happening in the solution process that produces variables drop from basis. Particularly, that problem occurred in my QP model when I disabled Aggregate (set aggregate=0). After that, the root relaxation was solved anyway but in a much longer time. Additionally, I have to say that it was just a test, so I solve my problem with the default value for aggregate and everything go well.

Thanks 

関連

• Numerics
• Warning

0

• 

  Maliheh Aramon

  • Gurobi Staff

  2023年07月05日 02:20

  Hi Jonathan, 

  The warning message means that the basis became singular. Therefore, the columns involved in the singularity (1 column in your case) needed to be dropped and replaced by another column. Gurobi would then switch to a higher precision to recover the basis and to avoid such a situation as much as possible in the rest of the run. 

  Best regards,

  Maliheh 

  1

サインインしてコメントを残してください。