Re: [Help-glpk] Save solution in GLPK

[Andrew Makhorin]

>> At the second simplex, GLPK starts with an objval=0 instead of the
>> precedent solution.
> 
>> Why?
> 
> If you add columns to the problem object, they become non-basic,
> so the optimal basis must remain at least primal feasible, however,
> it is primal infeasible (as seen from the solver output). Which
> changes in the problem object did you make before re-optimiziation?
> Looks like you changed bounds of some basic rows/columns.

Make sure that after addition of new columns to the problem object
they are non-basic and on their *zero* bounds. If a new column has
a non-zero bound, adding it (along with the column of the constraint
matrix) may make the basis primal infeasible.