Hello
Maybe you are reffering to this part from FAQ
QuoteFor example, if students S have 20 hours of activities with activity tag AT and another 2 hours of activities without activity tag (they have 22 hours in total, the ratio is 20/22=0.90), and you constrain them to 0 gaps per week and 0 beginnings at second hour and also the number of hours per day is large, say 12. Then adding a constraint students activity tag AT max 4 hours per day - alone - will not be perfect. A better solution will need you to add also a constraint students max 5 hours daily (if possible), to make the late slots not available for the students (it is a way to guide FET to the solution), or find other good ways to compensate the situation.
I think it is unlikely to happen :)
- For students, it is rare that a user assign a UNIQUE tag to 75% of activities !!
- Second, why a user want to use "Max hour daily with activity tag" to, in fact, set Max studying hours daily, while the same result can be obtained SAFELY with constraint: "Max hour daily for a student set" ?
in this case, the user is mesusing or misunderstanding the new contraint
For teachers: Max hours daily is directely related to a student set, and it is mot unlikely that a teacher teaches a students set more than 15% of total activitties
So I think you dont have to worry
QuoteHello
Maybe you are reffering to this part from FAQ
QuoteFor example, if students S have 20 hours of activities with activity tag AT and another 2 hours of activities without activity tag (they have 22 hours in total, the ratio is 20/22=0.90), and you constrain them to 0 gaps per week and 0 beginnings at second hour and also the number of hours per day is large, say 12. Then adding a constraint students activity tag AT max 4 hours per day - alone - will not be perfect. A better solution will need you to add also a constraint students max 5 hours daily (if possible), to make the late slots not available for the students (it is a way to guide FET to the solution), or find other good ways to compensate the situation.
Thank you for the good news :-)
Yes, I refer to this part, but there is more text, I reproduce it integrally:
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Question 1/25 September 2009: An observation for constraint teacher(s) or students (set) activity tag max hours daily:
This constraint is implemented correctly and is working good, but it is not perfect, which means that in extreme cases the time needed to generate a timetable might be longer than really necessary. You can give FET a hand in these extreme situations.
Notation: ATS=affected teacher or students set, means teachers or students sets affected by this constraint activity tag max hours daily (the problem does not appear for teachers or students sets which are not affected, which have no constraint activity tag max hours daily for them).
For extreme cases, the timetable generation might be longer or much longer than it should be. These cases refer to situations in which the total duration of the activities with the specified activity tag is high compared to the total number of hours of all activities for the ATS, combined with other conditions you use in the data. If the ratio of duration of activities with this activity tag over the total duration of activities for the ATS is over 0.75 or a normal (reasonable low) value, and you use constraints to control gaps or early for ATS, and the number of hours per day is higher than the possible hours for the ATS, the speed of generation might sometimes be slower or much slower than it should be.
In these cases, you are advised to use constraints teacher(s) or students (set) max hours daily for the ATS (without activity tag), or not available constraints for them in slots which are clearly impossible.
For example, if students S have 20 hours of activities with activity tag AT and another 2 hours of activities without activity tag (they have 22 hours in total, the ratio is 20/22=0.90), and you constrain them to 0 gaps per week and 0 beginnings at second hour and also the number of hours per day is large, say 12. Then adding a constraint students activity tag AT max 4 hours per day - alone - will not be perfect. A better solution will need you to add also a constraint students max 5 hours daily (if possible), to make the late slots not available for the students (it is a way to guide FET to the solution), or find other good ways to compensate the situation.
Conclusion: if, for the ATS, the ratio 'tag duration'/'total duration' is above 0.75 AND you use, for the ATS, contraints for gaps or early AND for the ATS the number of available slots per week is much higher than ATS's working number of hours per week AND if the time to generate a timetable is too long, you may need to address this problem.
Probably, in practice this problem will not appear and you need not to worry. But theoretically it exists.
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QuoteHello
Maybe you are reffering to this part from FAQ
QuoteFor example, if students S have 20 hours of activities with activity tag AT and another 2 hours of activities without activity tag (they have 22 hours in total, the ratio is 20/22=0.90), and you constrain them to 0 gaps per week and 0 beginnings at second hour and also the number of hours per day is large, say 12. Then adding a constraint students activity tag AT max 4 hours per day - alone - will not be perfect. A better solution will need you to add also a constraint students max 5 hours daily (if possible), to make the late slots not available for the students (it is a way to guide FET to the solution), or find other good ways to compensate the situation.
I think it is unlikely to happen :)
- For students, it is rare that a user assign a UNIQUE tag to 75% of activities !!
- Second, why a user want to use "Max hour daily with activity tag" to, in fact, set Max studying hours daily, while the same result can be obtained SAFELY with constraint: "Max hour daily for a student set" ?
in this case, the user is mesusing or misunderstanding the new contraint
For teachers: Max hours daily is directely related to a student set, and it is mot unlikely that a teacher teaches a students set more than 15% of total activitties
So I think you dont have to worry
I fear that a user may add an activity tag for 0.80 out of all teachers activities (like a teacher who teaches Math and Sports and he has 80% hours of Math from his hours and a constraint max hours daily for Math).