Originally posted by: david.rey

Hello,

I am experiencing a CPLEX Error 3019: "Failure to solve MIP subproblem" while trying to solve a MILP with CPLEX 12.4. I am using the C++ Concert API on a Windows XP machine.

I attached two pairs of parameters and models which generated the exception, could you help me resolve this issue?

Thank you,
David Rey.
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Originally posted by: SystemAdmin

I solved both your models (using your parameters) in the interactive optimizer (12.4.0). Both solved at the root node, in under one second, with no error message.

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
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Originally posted by: david.rey

Hello Paul,

What interactive optimizer did you use, the 32 or 64-bit version?

On my machine, I can solve both models successfully with the 64-bit version, however using the 32-bit version it does not seem to work: no optimal solution is given for any of the two models and the cplex log file is empty. Could the 32-bit version of the interactive optimizer be the cause of the issue?

I work on a 64-bit machine, but for practical matters, I had to compile my cplex code in 32-bit (mainly because the cplex code is triggered by another program developed in 32-bit). The models I had attached correspond to instances of a generic problem which I solve over a hundred times (sequentially) in one execution of my program. Has you may have noticed, the two models are different, hence meaning that one of them was at once solved successfully during the execution of my program.

The fact that both models can be solved successfully outside of my program using the 64-bit cplex optimizer suggest that the error comes from my code or from the 32-bit libraries, but then why am I getting those Error 3019 and what do they mean?

David.
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Originally posted by: SystemAdmin

David,

I used a 64 bit version (Linux). Have you tried running your compiled code on a 32 bit machine?

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
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Originally posted by: david.rey

Hello Paul,

No I haven't, actually it's quite a mess to run this code elsewhere than on this machine.

What is weird is that the exception isn't always triggered. I know my code might be the cause of the exception, but I had never experienced that exception before upgrading from Cplex 12.2 to 12.4.

David.
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Originally posted by: SystemAdmin

I just ran both problems on CPLEX 12.4 (32 bit), and got the same results that I got on a 64 bit machine. If reading the SAV files into the CPLEX interactive optimizer and then executing 'mip' produces errors on your machine, then something is broken in your installation.

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: david.rey

Hello Paul,

Indeed, I think that my problem could be related to my machine. I have been running my program for several days now without experiencing any exception whatsoever. I did not re-install CPLEX yet, but if the problem shows up again I might just do that.

Thank you for your assistance,
David.
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