On 08/12/2012 09:16 PM, Zell wrote:
Hi, all,
What are we supposed to do if Int64_Box does not support the not_equal constraints?
Int64_Box.add_constrain(x!-=0) does not work for me. PPL gives me: terminate called after throwing an instance of 'std::runtime_error' what(): PPL Java interface internal error
I think this error is expected.
Yes, the exception thrown is expected. You can not construct a Constraint object using relation symbol !=.
What would be the work-around then ? (except putting x!=0 to ((x>=1) or (x<=-1)) )
No, the thing above is not going to be a valid workaround (if you map the "or" into the upper bound operation of intervals). Strictly speaking, the only correct interval approximation for x != 0 is the universe interval (because the underlying approximation is meant to be convex).
If you already have a Box object B whose class is approximating a *rational* box with possibly open boundaries, then you can code your own function to refine the box wrt "constraint" (x != C): - if B satisfies (x == C), then make B empty; - if B satisfies (x >= C), then call B.refine_with_constraint(x > C); - if B satisfies (x <= C), then call B.refine_with_constraint(x < C); - in all other cases, B is unchanged.
If the Box class is representing *integral* boxes, then: - if B satisfies (x == C), then make B empty; - if B satisfies (x >= C), then call B.refine_with_constraint(x >= C + 1); - if B satisfies (x <= C), then call B.refine_with_constraint(x <= C - 1); - in all other cases, B is unchanged.
Enea.
Thanks. Zell.