Possibility to save and define a start timetable

[gesamtschule]

Hi,
as far as I know  a small change of the constraints will have a completely different result because the start table is randomly set. Today I talked with a friend about this and we had the idea that the behaviour will be more natural if it would be possible to start with a complete timetable.
Let me explain in which situation this would be useful: Let assume that we have a perfect timetable generated by FET and the school starts. After five weeks a teacher has an accident and we get a new teacher. Normally  I would try to make as less changes as possible. With FET I must generate a new timetable which a completly different result.  
I hope you understand the idea behind.
Niels

[Liviu Lalescu]

Dear Niels,

I think this option is simple to use in FET: say you obtained a timetable, then save data+timetable as (or, if you generate multiple, this is automatically saved). This is a .fet file, with added constraints activity preferred starting time. Keep this file. If you have some new teachers, remove the constraints activity preferred starting time referring to them and maybe other constraints, leaving the majority of activity preferred starting time constraints untouched. This way, you will work with a timetable similar to the old one. Maybe lower the weights of these constraints from 100% to 95% or something.

Please let me know what do you think about this.

[gesamtschule]

Hm I had the same idea, but I saw 2 problems:

1. If I changed the teacher of a activity, I'm not sure that the constraint will automatical deleted and even if, will this be enough so that fet can be find a new solution? Otherwise it could be become a really frustrating job: Starting the algorithm waiting, look for problems, find the constraint, delete them and so on.

2. As far as I know I couldn't neither in fet nor in the xmlfile easily select the constraints which are automtically added. So I'm unsure how easy it will be to adjust this constraints.

But perhaps you are right and it will be a good solution. Exist any experience with that? Otherwise I will see that I'll make some test with my school, but this won't be in the near future.

[Liviu Lalescu]

1. The constraints will not be removed, because each constraint has an id and the preferred starting time. So you will need to remove the constraints manually.

2. The constraints are the last added time (/space) constraints, of type activity preferred starting time (/room).

I have no experience with that, I am sorry. But maybe you could try to experiment.

[gesamtschule]

That's OK for me. I will try it and give you feedback.