[Bug-glpk] Re: Problem in post-solve

[Andrew Makhorin]

Thank you for your bug report!

> After "glpsol ax000000.mps" I get the message "OPTIMAL SOLUTION FOUND"
> followed immediately by the error message "Assertion failed: lpp != lpp;
> file
> source/glplpp2.c; line 941".
>
> It seems it is some problem with post-solve procedures because using "glpsol
> --nopresol ax000000.mps" the program finishes normally.

Just comment out (or remove) the following insist statement (file
glplpp2.c, line 941):

   insist(lpp != lpp /* this case is not tested yet */);

That statement was kept in the code because on developing the lp
presolver I could not find any lp instance to test that case.

After patching the code I tried solving your model with glpsol 4.1 and
the lp preprocessor enabled and got correct results.

Andrew Makhorin