Hello, I think I have stumbled on a glpk bug (version 4.28). On a particular problem, I get an assertion failure:
Assertion failed: spx->p != 0
Error detected in file glpspx02.c at line 602
Before getting the assertion failure, I get a numerical instability
warning
spx_simplex: warning: numerical instability (primal simplex, phase I)
BTW, I get this message even when calling glp_simplex with GLP_DUALP.
When I reverse the rows, I get PROBLEM HAS UNBOUNDED SOLUTION
This happens when I call glp_simplex from another language.
The funny thing is that when I write the problem into a file (cplex
format),
glpsol does not complain and finds an optimal value.
I know this is not a very comprehensive bug report.
Of course, I would be happy to give you more insights
-- tell me if there are debug options that could be useful for you.
I attach the cplex file and the output of lpx_print_prob:
file.133
Description: Binary data
file.txt.133
Description: Binary data
PS: Thank you for your work. Glpk is very useful to me. -- F. Besson
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