Proxy Assertion failed error

[Johannes Schaechinger]

Dear GLPK team,

 

I may have found a bug in glpk solver. If I try to solve the attached problem using glpsol v4.65 on Windows x64 with the command line call the optimization aborts with the following message

 

glpsol --lp proxy_assertion_test_problem.lp --tmlim 60 --pcost --proxy 10

 

Assertion failed: teta_lim >= 0.0

Error detected in file ..\src\simplex\spxprim.c at line 665

 

There is a problem with the proximity search. Without the proxy option, the solver works well.

Some online research got me to a github issue where a very similar bug is described, yet unsolved:

https://github.com/pywr/pywr/issues/728

 

For testing purposes, I installed glpk v5.0 via conda. Running the problem with this configuration leads to the same error.

On Ubuntu 20.04 LTS with glpk v4.65 the optimization is done without the error, but instead with the interim status “Bound exceeded […] Proxy heuristic terminated”, which I guess is no unusual behavior.

 

Hope this is enough information. Let me know if you need further details.

 

Regards

Johannes

proxy_assertion_test_problem.lp
Description: proxy_assertion_test_problem.lp