about gap

[kdsayang]

hi....

what is the differences between "max gaps per week for teacher" and "max gaps per day for teacher"??

I thought "max gaps per week for teacher" is a feature where u just set the gap thing once for the whole week and  "max gaps per day for teacher" is a feature where u can choose any day to set the max gaps for any teacher? Isn't it??

I have a proposal. Maybe u can create "min gaps for teacher" becoz I don't want my timetable too tight (no free period between classes). I want some gap between each classes. For example 2 or 1 period (Slot) between each class. Here the "min gaps" can be set to 2 or 1 and the "max gaps" can be set to higher than "min gaps" value.

[Volker Dirr]

In your sample are 1+4+1 gaps per week.
so "max gaps per week == 6" is true.
but "max gaps per week ==5" is false.

you have 1+4=5 gaps the first day.
you have 1 gap the second day.
you haven't gaps the other days.
so "max gaps per day ==5" is true.
but "max gaps per day ==4" is false.

i hope that help.

there is no 100% possibility to do min gaps per day/week. There are several workaround possible (with pseudo activities). Please have a look in the manual. http://www.timetabling.de/manual/FET-manual.en.html

Ask again if you don't understand or need more information.

[Liviu Lalescu]

Max gaps per week means that you restrict the number of total gaps per week. Per day means that each day must have maximum the number of gaps (for instance 1 per day and 3 per week).

You cannot put a constraint min gaps in FET, because of the way the algorithm works.

Are you suggesting constraint teacher(s) max hours continuously? I have thought of that in the past, as some others suggested it (suggestions made for FET-4, and the constraint was easy to add). But to add such a constraint for FET-5 seems very complicated. Please tell me, is such a constraint really important for your institution or other institutions?

Maybe you need to have a gap between building changes, in which case you can use the space constraint min gaps between building changes. But if your rooms are in the same building, it is not the case.

[kdsayang]

I think I understand about gap

Are you suggesting constraint teacher(s) max hours continuously?

NO

Please tell me, is such a constraint really important for your institution or other institutions?

YES it is important

Maybe you need to have a gap between building changes, in which case you can use the space constraint min gaps between building changes. But if your rooms are in the same building, it is not the case.

You're right on the gap between building changes.... I need 1 or 2 period between each classes.... One more thing, I think the lecturers need 1 or 2 period to gain strength back after a two hour lectures... Don't you think? They can gather their strength back to continue classes maybe after taking 1 to 2 period to take a break after a tiring 2 straight hours of lectures...  8-)

[Liviu Lalescu]

For lecturers: don't you want to have for instance teacher T1 to have only maximum 4 periods in a row? After that, a pause and after that other maximum 4 periods. Isn't that "constraint teacher max hours continuously"? I do not understand why you say this is not what you need.

If it is really important, I'll try to think of it in the next day(s).

[kdsayang]

For lecturers: don't you want to have for instance teacher T1 to have only maximum 4 periods in a row? After that, a pause and after that other maximum 4 periods. Isn't that "constraint teacher max hours continuously"? I do not understand why you say this is not what you need.

ohhh..... if u said that "constraint teacher max hours continuously" = teacher T1 to have only maximum 4 periods in a row then after that, a pause and after that other maximum 4 periods.... yes.. I want that... hehe....

I  thought "constraint teacher max hours continuously" = teacher T1 to have only maximum 4 periods in a row then after that NO pause and after that other maximum 4 periods. hehe

It is better if the user can CHANGE the "pause period" slot so the user can choose whether to place 1 or 2 period between classes

TQ

[Liviu Lalescu]

Is it not good enough a one hour pause? It is very complicated (impossible?) to be able to choose 1 or 2 periods gaps. Please let me know.

I'll begin working on this constraint, could you please send me your file so I can test the new constraint? It is easier if you could send it on my email address (see FET contacts page).

[kdsayang]

Is it not good enough a one hour pause? It is very complicated (impossible?) to be able to choose 1 or 2 periods gaps. Please let me know.

For me it's enough for 1 or 2 free period... Maybe you can make a min and max of free period like the min and max gap. If it is too complicated, then u just fixed it to make 1 period free (on and off like a tick or radio button) between each classes ONLY for the same lecturer...

I'll begin working on this constraint, could you please send me your file so I can test the new constraint? It is easier if you could send it on my email address (see FET contacts page).

on the way my friend... hehe

[Liviu Lalescu]

I can only impose a constraint max hours (in fact periods) continuously for a teacher or for all teachers. So, it will impose that after x (say 4) periods they will have 1 period gap at least.

I will begin working now on this constraint. I have thought and it seems realizable.

I think it will be ready today or tomorrow.  I'll let you know.

PS: Why did you add constraints teacher max days per week for many teachers with 5 days, when you have a 5 days week? The constraints are useless, only the one with 4 days is useful.

[kdsayang]

I can only impose a constraint max hours (in fact periods) continuously for a teacher or for all teachers. So, it will impose that after x (say 4) periods they will have 1 period gap at least.

I will begin working now on this constraint. I have thought and it seems realizable.

I think it will be ready today or tomorrow.  I'll let you know.

ok.... but I think it is better if FET can assign X free periods depends on the user need after X period of classes. For example, If subject A is 4 periods, after that, the free period is 1 (the user input 1 for free period after the classes). Another example is, If subject B is 3 periods, after that, the free period is 2 (the user input 2 for free period after the classes)... I think the best way to handle this problem is to let FET automatically handle IT as long as there is a FREE period( does not matter whether it 1, 2, 3 or 4 FREE period) between each classes. You can get rid the trouble to make the user to insert the input (FREE period) into FET ... just a suggestions... U know the best....

PS: Why did you add constraints teacher max days per week for many teachers with 5 days, when you have a 5 days week? The constraints are useless, only the one with 4 days is useful.

hehe.. good question.. hehe.. actually I want FET to fully utilized all the room....but I found that I can achieved this by using Min n  days between a set of activities = 2....  

[Liviu Lalescu]

I cannot say to FET: leave 2 periods, I can only say: leave at least 1 period. In practice, there will be 1, 2 or more free periods, but guaranteed only one. It is because of the algorithm that I cannot make it with 2 or more. I hope it is good enough for you.

The constraint will be named teacher(s) max hours continuously and you can specify the maximum amount of contiguous hours (periods) for teacher T or all teachers, for instance 4.

[kdsayang]

I cannot say to FET: leave 2 periods, I can only say: leave at least 1 period. In practice, there will be 1, 2 or more free periods, but guaranteed only one. It is because of the algorithm that I cannot make it with 2 or more. I hope it is good enough for you.

oooooooo.... I understand.. More than enough for me.. hehe

The constraint will be named teacher(s) max hours continuously and you can specify the maximum amount of contiguous hours (periods) for teacher T or all teachers, for instance 4.

Does this mean that I can add two constraint which is 4 and 3 period?? This is because, my time table mainly consist only 3 and 4 max hours continuously period....

[Liviu Lalescu]

Does this mean that I can add two constraint which is 4 and 3 period?? This is because, my time table mainly consist only 3 and 4 max hours continuously period....

Means that you can add constraints for each teacher, one teacher has for instance max 3 hours continuously and another 4.

The algorithm is ready now, I will begin implementing the interface and open/save code and test after that. I just tested for your file a bit and it is OK.

I have to add a check. Say activity A has duration 4. Then you cannot a constraint of type max hours continuously with less than 4 (say 3). Is that OK with you?

[kdsayang]

Means that you can add constraints for each teacher, one teacher has for instance max 3 hours continuously and another 4.

The algorithm is ready now, I will begin implementing the interface and open/save code and test after that. I just tested for your file a bit and it is OK.

OK.... Same features that i want.. 8-)

I have to add a check. Say activity A has duration 4. Then you cannot a constraint of type max hours continuously with less than 4 (say 3). Is that OK with you?

Yes... It's fine by me

[Liviu Lalescu]

Great news! I made this (max hours continuously constraints). It was not that hard as I thought. Please get the latest version from lalescu.ro/liviu/fet/download/test/ (you can see this link in the News section also).

Please let me know if everything is OK, so I can release in a few days a new version.