Key takeaways
- Specialist-room needs are hard constraints when the lesson cannot run in a general room.
- Room availability can make a timetable infeasible.
- Capacity and equipment limit how many groups can use a space at once.
- Model room type, availability, capacity, and equipment before judging the timetable result.
What belongs in the room model?
The room model should say which activities can use which spaces. For specialist teaching, the room type is a hard constraint when the wrong room makes the lesson impossible.
The model also needs room availability. A room can be suitable and still unavailable. The solver needs both facts before it can place the lesson.
Room and equipment facts to capture
Capture facts that change whether a lesson can run.
- Room type, such as lab, workshop, standard classroom, or other specialist space
- Room availability by period
- Room capacity for the group using it
- Equipment that is required for the activity
- Stations, benches, machines, or similar capacity limits
- Activities that can use only a specific room type
How to prepare room constraints
Prepare room data before generation so infeasibility means something clear.
- List activities that need a specialist room.
- Assign the acceptable room type for each activity.
- Record when each suitable room is available.
- Record capacity and equipment limits.
- Check whether too many groups need the same scarce space.
- Keep convenience preferences separate from hard room requirements.
Why a free room may still be wrong
A free room is not enough. If the room lacks the required equipment, capacity, or specialist type, the lesson may not be deliverable.
This is why room constraints should be treated as placement rules, not as a cleanup task after generation. The solver needs to know the real limits before it can find a feasible timetable.
Room-constraint review checklist
Before generation, confirm that specialist-room needs are hard where needed, room availability is recorded by period, capacity limits match the groups using each room, equipment limits are explicit, scarce shared spaces are checked for competing demand, and room preferences are not confused with room requirements.
How room constraints interact with other constraints
Room constraints work alongside teacher, class, and curriculum constraints. A valid placement needs the right teacher, the right group, the right time, and the right space.
When no placement exists, room availability or specialist capacity may be the cause. Check room facts before treating the result as a solver-quality problem.
Questions planners ask about room and equipment constraints
When is a room rule hard?
It is hard when the lesson cannot run in the wrong room type. A lab lesson placed in a standard room is not a usable solution.
Why does room availability cause infeasibility?
The solver must find slots where the right room type is available. If the required room is not available when the group, teacher, and lesson can meet, no feasible placement may exist.
Should equipment be separate from room type?
Yes, when equipment or capacity changes what can be taught there. Stations, benches, and machines can limit how many groups can use a space at the same time.