GNOME Bugzilla – Bug 679027
non-linear solver does not respect constraints
Last modified: 2012-07-03 14:20:01 UTC
Steps to reproduce the problem: - open the attached file - open the solver - minmize cell age!H1 by modifying cells thinning!H1:H5 - use a non-linear model - assume non-negative values - run the solver => the solution found gives a negative value in cell thinning!H4.
This is part of item #5 of bug #620368 *** This bug has been marked as a duplicate of bug 620368 ***
No attachment -- I'd be interested in such a sample. You can work around the problem by imposing large (but not infinite penalties) on going beyond the constraint. Something like max(-1e6*x42,0) for a variable not allowed to be negative. That's not particular elegant. but it ought to work. In fact, it might work better than respecting the constraints (whenever I get around to take) because there might not be a whole lot to do beyond throwing up a "no convergence" message.
Sorry, the file is here: http://parrenin.frederic.free.fr/download/bugzilla/dating-model.gnumeric
Something has changed since the bug report was filed. age!H1 no longer contains an expression and thinning!H1:H5 no longer the variables.
Sorry, this is now age!L1 for the variable to minimize and age!3036:3040 for the variable to tune.