[Roberto] bug3.dat [...] Assume almost nothing from the input: only generators are up to date and not even necessarily minimized. Wild guess: perhaps add_and_minimize() does not minimize?
I tried that too, a few days ago. But my wild guess was slightly different: minimize() does not minimize! If you follow the way x changes, you see that, after the execution of x.minimize(), the constraints system of x is of course "up-to-date" and "minimized", but it's different from the "normal" minimized form: i.e., x.minimize() gives as output exactly the matrix we don't like. Please note: I didn't check everything with the latest versions of our code, and I had messed up the code quite a bit before testing; so, try by yourself before speculating. I may be wrong. Andrea.