This function creates and returns a constraint. When that constraint is posted, it insures that each value of the array val will be required by exactly one set variable of the array vars.

If the argument val is not mentioned, the array val is formed by the union of the values involved in the set variables of vars.

If you do not explicitly state a filter level, then Solver uses the default filter level for this type of constraint. The optional argument level can take one of the two values: IlcBasic, IlcExtended. The domain reduction during propagation depends on the value of level.

IlcBasic is the lowest value.

IlcExtended causes more domain reduction than IlcBasic; it also takes longer to run.

See IlcFilterLevel for an explanation of filter levels and their effect on constraint propagation.