Continuing optimization...

Answered

D

• September 27, 2023 19:38

What does it mean when I see this in the log for a while "Continuing optimization... ", even though I used the parameter: model.Params.OutputFlag = 1, to get detailed information during the optimziation? Is the model stuck? how do I fix it?

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  Riley Clement

  Gurobi Staff

  • September 28, 2023 00:41

  Hi,

  You will see this message if you resume a solve after it had previously terminated.  It is letting you know that the internal structures and data from the previous solve are being used and you are not starting from scratch.

  Any chance you are using Jupyter Notebooks?  I can see this arising if you were to run an optimization, change some parameters in a subsequent cell, then call optimize() again.

  If you need to reset the model then you can use Model.reset()

  I would strongly recommend you make yourself familiar with our reference manual, it will help your understanding a lot.

  - Riley

   

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  D

  • September 30, 2023 05:07

  

  

  

  Yes, I am using jupyter notebook. 

  The problem is that it is stuck and it doesn't give any further messages after 

  Continuing optimization...

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  Riley Clement

  Gurobi Staff

  • September 30, 2023 08:02

  How long is it like that for?

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  D

  • October 01, 2023 04:27

  

  

  

  over 3 hours

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  Riley Clement

  Gurobi Staff

  • October 03, 2023 03:04

  Hi Dana,

  My suggestion would be to write the model out to an MPS file, and run Gurobi via the command line, and see whether the solver seems to stall.  You certainly won't see the message "Continuing optimization..." but it would be good to confirm if you also see hours of inactivity in the output.

  Jupyter Notebooks can be a bit misleading.  Sometimes a cell appears to be running but it is not.  Sometimes a notebook appears to be running but it is not, and has silently failed.  Ideally we rule this out.

  - Riley

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