Originally posted by: JorisK

Dear,

I'm currently implementing a Branch-and-Cut using cplex. For the cut procedure, I'm using IloCplex.LazyConstraintCallback. While implementing, I mistakenly wrote the following in the implementation of the main() function of my LazyConstraintCallback:

IloConstraint subtourConstr=this.add(cplex.addGe(subtourExpr, 0, "subTour"));

What I should have written:
IloConstraint subtourConstr=this.add(cplex.ge(subtourExpr, 0, "subTour"));

Nevertheless, when I run the first line, a pretty hard crash follows:

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1. A fatal error has been detected by the Java Runtime Environment:

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1. SIGSEGV (0xb) at pc=0x00007f7995cc4e86, pid=5436, tid=140160405821184

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1. JRE version: 6.0_24-b24
2. Java VM: OpenJDK 64-Bit Server VM (20.0-b12 mixed mode linux-amd64 compressed oops)
3. Derivative: IcedTea6 1.11.5
4. Distribution: Ubuntu 11.10, package 6b24-1.11.5-0ubuntu1~11.10.1
5. Problematic frame:
6. C http://libcplex124.so+0x463e86 CPXcutcallbackadd+0xc6

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1. An error report file with more information is saved as:
2. /home/jkinable/workspace/RingStar/hs_err_pid5436.log

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1. If you would like to submit a bug report, please include
2. instructions how to reproduce the bug and visit:
3. https://bugs.launchpad.net/ubuntu/+source/openjdk-6/
4. The crash happened outside the Java Virtual Machine in native code.
5. See problematic frame for where to report the bug.

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Whenever possible, I would suggest to catch this error in a bit more elegant fashion, instead of crashing the Java Runtime environment.

Ps. I could not find a channel where I could file bugs related to cplex, hence my post on the forum.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

There is no explicit website for bug reports. So reporting them in the Forum is fine.
As you observed, modifying a problem via addLe() and friends while it is being solved is unsupported behavior. Functions like addLe() even have this comment in their reference documentation:

Do not use this method in a callback to modify the model currently being optimized.

So undefined behavior (in this case a crash) is acceptable.
Of course, we cannot guard against all potential mis-uses of CPLEX. Still, I filed a user wish to see if we can handle this error more gracefully and throw an exception instead.
Thanks for your report!
#CPLEXOptimizers
#DecisionOptimization