About MemLimit

Answered

Charitha Heendeniya

• November 03, 2022 07:28

Dear all,

I'm trying to use MemLimit parameter 

e = Env("gurobi.log", params={'MemLimit': 31,
                              'PreSparsify': 1,
                              'MIPFocus': 3,
                              'NodefileStart': 0.5,
                              'Heuristics': 0.3,
                              'Presolve': 1})

But when I do that, the OutOfMemory error is raised well before the 31GB RAM use. In fact the operation crashes at about 20GB memory use (checked via task manager). Do you know why this might happen?

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  Charitha Heendeniya

  • November 03, 2022 08:13

  

  

  Adding one more observation: OutofMemory is observed right at the end of the presolve. 

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  Matthias Miltenberger

  Gurobi Staff

  • November 03, 2022 10:58

  Hi Charitha,

  it may happen that Gurobi requests more memory but doesn't use it, yet. The idea of the MemLimit parameter is mainly to allow a more controlled termination without actually using too much memory and disturbing other processes.

  Did you try running without setting the MemLimit parameter?

  Cheers,
  Matthias

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  Charitha Heendeniya

  • January 12, 2023 15:55

  

  

  Sorry for the late reply. I did experiment with and without it. Without the MemLimit parameter, the OS takes care of the problem, but that occurs later. So probably, the behavior of Gurobi MemLimit is, as you said, related to some anticipated future memory use. 

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