Timetable don't close

[davvidde]

Dear Liviu,
It's the second year that I use FET but this time I've gone into a stuck. I have generated a timetable for my school and make every arrangement succesfully but, at last moment, I decided to make a manually inversion of an hour for two teacher in the same day. I saved the timetable with all constraint and I made the inversion by change the constraints "an activity has a preferred starting time" which FET adds when the timetable is freezed. I also removed all constraints for the two teachers that could interfere with the placeing of the two activities and I started the timetable generation.
The timetable don't close because FET refuses to place one of the two activities even if the last place is free and the teacher is also free. Could you help me to find the cause? Could be this a bug? I attach my .fet file.
You could answer me in italian too.

Davide

[Liviu Lalescu]

The cause is the max gaps constraints for all teachers and for Nardi.

[davvidde]

Thanks Liviu, but I ever believed that the "max gap constraint for a teacher" has better priority than the "max gap for all teacher" which I consider the default.
It is better to set a default gap for all teacher and set a variation of the gap for a single teacher because let introduce me less constraints in the timetable.
If the max gap constraint is specified in either the two sections what is the rule? The lowest has priority or what ever?

Thanks.
Davide.

[mbarsan]

I remember that all constraints work in a AND relation.
This means that all constraints must be respected.

You ask for all teachers max 3 gaps per week.
You ask - also - for Nardi max 4 gaps per week.

Simply, second constraint will be ignored, because the first one includes the second.

[davvidde]

Thanks. I forgot this rule in a gap of a year.
Davide.