Hide or unhide a constraint.

THe following defines a constraint and then sets it as hidden:

declarations
 x,y,z: mpvar
end-declarations

c:= 4*x + y -z <= 12
sethidden(c, true)

At its creation a constraint is added to the current problem, but using this procedure it may be hidden. This means that the constraint will not be contained in the problem that is solved by the optimizer but it is not deleted from the definition of the problem in Mosel. Function ishidden can be used to test the current status of a constraint.

ishidden.