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I am running MIP optimization using CPLEX studio v12.9 on Ubuntu 18.09 using C++ programming language. My problem has about 6000 variables and about 22M constraints. The cluster on which i am running the program has 24 CPUs with 125GB of RAM. The problem does not run out of memory but crashes with 0x9 signal from the CPU. Optimization was working fine with correct results earlier when the problem had about 2k variables with roughly 2M constraints.

What could be the possible reason for this problem?

Thank you.

anirudh puligandla
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This question was cross-posted here. For convenience, here is my answer:

This is just a guess, but could it be that the Linux OOM Killer is the culprit? See this stackoverflow thread which links to an article about the OOM Killer and ways to search log files to determine if it is affecting you.

rkersh
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  • Thanks for the answer. I think OOM is indeed creating trouble here as the problem works fine when i use fewer variables in the optimization procedure. Also, while looking closely i noticed that a couple of constraints were incorrect which caused the optimization to never reach a solution and eventually get killed by the OOM. And sorry for crossposting. I thought the one on IBM forum did not get posted as i could not find the question later. – anirudh puligandla Oct 03 '19 at 14:11