Re: [Help-glpk] [Fwd: help on interpreting sensitivity analysis]

[Andrew Makhorin]

> Thanks a lot for the quick reply. If my plot is incorrect then maybe it would 
> explain my doubts. However, I cannot see why it is incorrect. In your naming 
> of variables and constraints the xx axis would represent x1 and yy axis x2. 
> The blue line is c1, the red c2, and the yellow c3. The interior of the 
> triangle thus marks the feasible region.

On your plot I didn't find the point that corresponds to the basic
solution found by the solver. Just check it, may be I'm wrong.

> 
> If this is correct (please apologise if I'm making some basic mistake here), 
> then I don't understand how the current basis remain optimal for any positive
> objective coefficient after x1>=3.28571, as you said, since for approximately 
> x>6.5 there is no feasible region.
> 

If the obj coefficient at x1 is increasing, the current basis is *not*
changed remaining optimal for *any* positive obj. coefficient, i.e. x1
keeps its current value 3.28571. Please read the reference manual more
carefully.