An IP-based heuristic for the post enrolment course timetabling problem of the ITC2007

Track 2 of the international timetabling competition 2007 was a post enrolment course timetabling problem. A set of events has to be assigned to a timeslot and to a room such that all students are able to attend their requested events while not violating the hard constraints. There are also soft constraints that make the timetable “nicer”. We present a deterministic heuristic that assigns events to timeslots based on an LPsolution constructed with column generation. We get an integer solution by fixing columns one at a time. This heuristic finds a solution that obeys all the hard constraint for 23 of the 24 instances of the competition. The generated solution is improved by selecting a set of events that are reassigned by solving an integer program. This IP minimizes the number of soft constraint violations under the restriction that no hard constraints are violated. Comparing the results of our heuristic with the results of the five finalists of the competition, shows that our approach is competitive.