On Wed, 2 Jun 2004, Henri Gourvest wrote:
I have a special constraint:
x1 + x2 + x3 >= 2
or
x1 + x2 + x3 <= 0
I want the result set to be:
0 0 0
1 1 0
1 0 1
0 1 1
1 1 1
But the constraints seem to be unsatisfaible because I don't know how to
write the "OR" constraint.
I'm not sure it is possible but perhaps someone have an idea ...
This is really a MILP question, not a GLPK question.
I'm assuming that x1, x2, and x3 are binary variables.
There are 3 combinations you want to eliminate:
001, 010, and 100.
Add the following constraints:
x1 + x2 - x3 >= 0
x1 - x2 + x3 >= 0
-x1 + x2 + x3 >= 0
This technique won't always get you the convex hull,
but in this case I think that it does.