[Bug-glpk] assertion failure glpspx02.c

[Frédéric Besson]

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

Part1.txt
Description: Text document

file.txt.133
Description: Binary data

Part2.txt
Description: Text document