Hard constraints

Hard constraints can be applied to a rule to require that Auto-Assignment always follows the rule when creating schedules. As opposed to standard constraints, Auto-Assignment does not break a hard constraint rule under any circumstances. If it cannot find a solution that does not break a hard constraint, it does not assign any shifts.

Hard constraints should be used with caution. When used with rules that contradict each other, hard constraints can make it impossible for Auto-Assignment to find a feasible schedule.

It is not recommended to use minimum rules as hard constraints. As an example, you configure a rule where employees get a minimum of 40 hours per week as a hard constraint. If there are not enough shifts in a given week to give everyone 40 hours, Auto-Assignment would not assign any of the shifts, since there is no solution that satisfies the rule. For the same reason, the rule Maximum Sched Days Off Per Time Period is also not recommended to be used as a hard constraint. If these rules are used as standard constraints, Auto-Assignment would break them when there are not enough shifts, and the schedule could still be created.

Shifts that are already assigned to employees when Auto-Assignment is run may make it impossible to create any schedule that does not contradict a hard constraint rule. In this case, Auto-Assignment does not schedule any shifts, and the existing shifts remain in the schedule.

For employees who have assigned shifts or LTAs that exceed the defined hard constraint value, the hard constraint for the rules Maximum Hours Per Time Period and Maximum Shifts Per Time Period are temporarily adjusted by the Auto-Assignment system. Even when existing shifts do not comply with these rules, the schedules are generated by the Auto-Assignment system by automatically increasing the constraint values during the optimization process.