When the ‘Generate’ Button is pressed on the Construction Screen, our software will automatically test for ‘infeasibility’.

**This relatively fast test can only establish if your timetable cannot be scheduled and passing the text does not necessarily mean that your timetable can be scheduled.**

During this test, the software examines the timetable for curriculum layout problems which might prevent the solver from completing the timetable. It examines teaching groups across all years of the curriculum that share a teacher, room, room pool or students. None of the lessons of these teaching groups can ever be scheduled for any of the same periods as there would be a clash or teacher, student or room. This becomes a problem if the total number of lessons from these interconnected groups is greater than the number of periods on the timetable grid. The teaching groups which make up this collection must be examined and you must make some modification to teacher, room, room pool or students before the timetable can be scheduled fully. Our software will suggest teachers or rooms which will need to be modified in order to remove this infeasibility.

The software will also examine each year to see if the curriculum specified in Class Data can be scheduled.

Consider this Year 5 curriculum:

You will see that there are 36 blocked lessons and 6 lessons remaining in core for each base class. Examine the subject '*Physical Education*' in core - there are 2 PE teachers, EMUR has 3 double lessons (6 lessons) and MGAR has 2 double lessons (4 lessons). This is feasible as there are 6 periods available to schedule the core lessons and no teacher has more than 6 lessons than in core.

Now consider the curriculum shown below:

It is almost the same as the curriculum above but with one change - SPHE has been moved from core to block as the SPHE Department asked that their single lessons of SPHE would take place concurrently to allow for modular lessons.

At first glance, this seems to be a simple change with just one extra block and only a single lesson in that block. However, this change is quite significant and it would make the year 5 curriculum infeasible.

Examine the core curriculum and you will see that this change has meant that there are now only 5 periods available for the core lessons as the blocks would require 37 periods to be scheduled. EMUR has three double periods (6 lessons) of PE so she would therefore need six periods to schedule them. However, there are only five periods available. This means that it would be impossible to schedule the PE lessons of EMUR. Switching one of her double lessons to the other PE teacher, MGAR would not solve the problem as MGAR would then have 3 double periods (6 lessons)

So allowing the extra block of SPHE creates a problem unless another PE teacher can be found. The most logical move here would be to remove the SPHE block and return the lessons to the core section.