Hi Liviu Lalescu and Volker Dirr,
I saw the constraint "A teacher's not available time" with weight 100% necessary. (Hard constraint)
I wonder whether we can set this constraint with less than 100%, such as 90%, 95%? (Soft contraint)
Because, some teachers ' requirement are only their desires.
Example: It's far from Teacher A's house to the school, so he wishes not to teach at the first hour of day.
But It is only his wish, It is not compulsory. It is good if Time table adapts his requirement, but it is ok also if not.
In my opinion, this soft constraint will make time table result to be finer? Do you think so?
i don't think so, because of several reasons:
a) some teacher must also come later at my school (because they need to bring their children into the kindergarten. so if i don't set them 100% not available in the 1st hour, then they might be 5-10 minutes too late). i just set them 100%. So the teachers are satisfied. If it is not possible, then "I" can decide what is needed more. (But so far it was always possible :-)
b) users will do stupid stuff if something like that is possible: for example 95% not available monday 1-3 hour. If you think a bit on such a constraint, then you will see that it is pretty nonsense, because FET might place an activity into 1st, 2nd and/or 3rd hour. But in fact that doesn't help if he need that time to come later to school.
c) if i remeber correct, then results were pretty stupid/useless with such a weight. so even if you add such a 95% weight constraint it has nearly no effect. it will just blind/glare the FET user.
PS: I am always very stick to my timetable :-) I use always only 100% to all constraints. I don't want to have results with conflicts.
You can use constraint activities preferred times, specify only the teacher (and ignore the warning).
You can think also of the constraint teachers interval max days per week.
yes. the max intervall 1st hour with 100% should be a fine constraint if you can't disallow all hours. If you have got a 5 days week, then it mean you can allow only 1 time the first hour. (so it is something like a 80% not available, just much better, because it is at least 80%.)
Yep, thank Liviu Lalescu and Volker Dirr so much :).