Re: [Bug-glpk] [Fwd: preprocessing goes into infinite loop]

[Andrew Makhorin]

Hi Xypron,

> when running glp_simplex on the problem, I get this output:
> GLPK Simplex Optimizer, v4.47
> 45 rows, 5 columns, 123 non-zeros
>       0: obj =   5.000000000e+00  infeas =  3.750e+01 (0)
>      37: obj =   1.400000000e+01  infeas =  8.833e+00 (0)
> PROBLEM HAS NO FEASIBLE SOLUTION
> 
> I then used John's coding to write the appended file in CPLEX format.
> 
> glpsol --lp test.lp leads to the following error in the presolver:
> 
> Preprocessing...
> Assertion failed: q->lb < q->ub
> Error detected in file ..\src\glpnpp03.c at line 556

This diagnostics is not relevant due to floating-point overflow (please
see my recent posting to bug-glpk). The glpk code is not intended to
work with Inf's and NaN's, so such values completely destroy the program
logic.

> 
> I would not have expected such an error.
> 


Andrew Makhorin