Reducing the room usage

The rules descibed in:

Optimizing the room usage for students
shall help you to achieve the room assigment that is acceptable from the timetabling point of view.

However once you have the timetable ready you may want to reduce the room usage for example to save on cleaning costs or to allow more room renting.

Here are some tips:
GymRoom can only be used 4 days per week(GymRoom has to be free on 3 afternoons)
or
Concentrate groups of lessons into fewer classrooms

Notes:
- add these rules only after you have an acceptable timetable.
- generate with relaxation and use low importance for these rules so that yuo do not create much worse timetable for teachers and students just to fee the Gym room for renting on one afternoon.