Constraint

A constraint is a condition placed on a timetable.

There are three classes of constraints - hard, soft and dual. All constraints except the dual ones can be configured to be either hard or soft in each configuration set.

Hard

Hard constraints contribute to timetable health and must be all satisfied in order for a timetable to be feasible.

Soft

Soft constraints contribute to timetable fitness (quality) and it is desirable to satisfy as many of them as possible.

Dual

Dual constraints are both hard and soft and the choice is made at the point of configuration. For example when a preferred room is marked as required, the constraint will be applied as hard.