Creates and returns an empty IRange object.

Creates and returns an instance of IRange initialized to represent the constraint lb <= expr <= ub.

Creates and returns an empty IRange object with the name specified by name.

The new IRange object is initialized to represent the constraint lb <= 0 <= ub. The new IRange object is assigned name as its name. This method is typically used in an application that applies column-wise modeling to fill in the expression for the ranged constraint while creating the variables.

Creates and returns an instance of IRange initialized to represent the constraint lb <= expr <= ub and assigned the name name.