combination of constraints

[silvia]

hello,
I have a doubt. I don't know if this can be done in FET with a combination of constraints. If FET assigns an activity in 5th hour and an activity in 7th hour, can I tell FET to leave free the 6th hour (for lunch). SO, is there a way of telling FET to leave the 6th hour free only if that teacher works at 5th and 7th?

[Liviu Lalescu]

Probably the answer is no, I don't see a solution to this.

[Chafik Graiguer]

Hi all
I am a total newbie about programation and logarithms
All I can do is to give some general ideas, so forgive me if my ideas are so vagues !!

There is a feature in FET which needs to be extended:
The interval
wgich is used in the constraint: works in an hourly interval max days per week

This way , we could build other constraints:
1-suppose we have two possibilities for lunch : period 3-4 or 5-6
A new constraint would be: Two periods incommpatible same day
so teacher/students can have lesson either periods 3-4 or 5-6 but not both

2-we can also deal with Silvia's case by a new constraint like this:
Max hours continuosely for a teacher in an interval
Silvia would set: Max=1 for period 5-7

[Volker Dirr]

Two periods incommpatible same day
so teacher/students can have lesson either periods 3-4 or 5-6 but not both

You can do that with the new constraint that is included in the current snapshot.
just add an activity tag "lunch" and say the activity tag is allowed only once per day.
but it doesn't always help, because it mean you need an activity "lunch". that will be difficult if you have teachers that teach only a few hours per week and also use a max gaps constraint.

similar if you just simply use a min n day constraint.

2-we can also deal with Silvia's case by a new constraint like this:
Max hours continuosely for a teacher in an interval
Silvia would set: Max=1 for period 5-7

by this you don't need a "lunch" activity. yes, that is maybe a nice solution. i am not 100% sure if it fit to all teachers, because i don't know about silvias teachers that work only half time.