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FET Support (English) => General Stuff => Topic started by: lebwoski on February 10, 2014, 08:32:01 AM

Title: min/ max double periods
Post by: lebwoski on February 10, 2014, 08:32:01 AM
Hi,

i have an activity with a duration of 6, which should be teached in 1 or 2 double periods. Because of this i created an activity with 4 sub activities
2/6, 1/6, 1/6, 1/6, 1/6. I set "min-Days between activities" to 1 an the weight to 95%. Generating a plan, sometimes i get 3 double periods. Is there a way to force fet to build maximum 2 double periods.

Thanks
Title: Re: min/ max double periods
Post by: Liviu Lalescu on February 10, 2014, 08:53:09 AM
Teacher/students activity tag max hours daily.

Or

4 min days constraints 100% between 2/6 and each of the 1/6.
Title: Re: min/ max double periods
Post by: lebwoski on February 10, 2014, 10:24:21 AM
Hi and thank you for your replay:

I didn't test it, but if i put 4 min day constraints like

1: 2/6 and 1/6a
2: 2/6 and 1/6b
3: 2/6 and 1/6c
4: 2/6 and 1/6d

isn't a timetable like

Day I: 2/6
Day II: 1/6a and 1/6b
Day III: 1/6c and 1/6d

possible?

But i maximum want to allow:
Day I: 2/6
Day II: 1/6a and 1/6b
Day III: 1/6c
Day IV: 1/6d

and minimum

Day I: 2/6
Day II: 1/6a
Day III: 1/6b
Day IV: 1/6c
Day V: 1/6d


Thanks
Title: Re: min/ max double periods
Post by: Bobby Wise on February 10, 2014, 11:02:33 AM
Use

Advanced
Spread the activities evenly over the week
Title: Re: min/ max double periods
Post by: Liviu Lalescu on February 10, 2014, 11:09:23 AM
Bobby, the Spread activities over the week does not function as he wants; he needs something even more advanced.

lebwoski, sorry, I understood that you don't want more than 2 hours of those activities per day.

I would now suggest this:

4 min days constraints 100% between 2/6 and each of the 1/6; then, 3 min days constraints 100%: 1a <-> 1c, 1a <-> 1d, 1c <-> 1d.
Title: Re: min/ max double periods
Post by: lebwoski on February 10, 2014, 12:52:09 PM
Hi, and thanks again,

but i want to allow one further double period. If fet finds a solution with two double periods and one single period, this should be an allowed solution. If fet finds a solution with one double period and 4 single periods this  also should be an allowed solution. If fet finds a solution with 3 double periods this should not be allowed.

Idea: I make 4 min days constraints 100% between 2/6 and each of the 1/6; then, 2 min days constraints 100%: 1a <-> 1c, 1a <-> 1d and 1 min days constraints with weight < 100% between 1c <-> 1d. So fet can create a double period from 1c & 1d.

- If this works, which value should i use for the third constrains (min days constraints between 1c <-> 1d)?

One Question
If fet generates a plan an find a timetable where 1a & 1d build a double period and 1c & 1d not. For fet this is no solution (100% 1a<->1d), but for me it is,because 1a and 1c are equivalent and can be swap in this plan.  Is this right, or do fet also swap  equivalent activities?

Title: Re: min/ max double periods
Post by: Liviu Lalescu on February 10, 2014, 01:50:58 PM
Quote from: lebwoski on February 10, 2014, 12:52:09 PM
Hi, and thanks again,

but i want to allow one further double period. If fet finds a solution with two double periods and one single period,

You mean two single? This is allowed, as 1b may be in the same day with 1a, 1c or 1d.

Te recapitulate: 100% 2,1a, 100% 2,1b, 100% 2,1c, 100% 2,1d, 100% 1a,1c, 100% 1a,1d, 100% 1c,1d. Then, 95% 1a,1b,1c,1d (or 95% 1a,1b, 95% 1b,1c, 95% 1b,1d if you prefer like this).

Quote
this should be an allowed solution. If fet finds a solution with one double period and 4 single periods this  also should be an allowed solution. If fet finds a solution with 3 double periods this should not be allowed.

Idea: I make 4 min days constraints 100% between 2/6 and each of the 1/6; then, 2 min days constraints 100%: 1a <-> 1c, 1a <-> 1d and 1 min days constraints with weight < 100% between 1c <-> 1d. So fet can create a double period from 1c & 1d.

- If this works, which value should i use for the third constrains (min days constraints between 1c <-> 1d)?

One Question
If fet generates a plan an find a timetable where 1a & 1d build a double period and 1c & 1d not. For fet this is no solution (100% 1a<->1d), but for me it is,because 1a and 1c are equivalent and can be swap in this plan.  Is this right, or do fet also swap  equivalent activities?

FET will not swap equivalent activities (1a and 1c are different). You need to take care of this.
Title: Re: min/ max double periods
Post by: lebwoski on February 10, 2014, 02:04:51 PM
Hi,
i think that is what i need:
Quote100% 2,1a, 100% 2,1b, 100% 2,1c, 100% 2,1d, 100% 1a,1c, 100% 1a,1d, 100% 1c,1d. Then, 95% 1a,1b,1c,1d (or 95% 1a,1b, 95% 1b,1c, 95% 1b,1d if you prefer like this).

Is 95% 1a,1b,1c,1d  really the same as   95% 1a,1b, 95% 1b,1c, 95% 1b,1d ?

Is 95% the right weight, if it is regardless, if 1b occurs in a double periode or as a single period?

Thank you
Title: Re: min/ max double periods
Post by: Liviu Lalescu on February 10, 2014, 02:41:59 PM
Quote from: lebwoski on February 10, 2014, 02:04:51 PM
Is 95% 1a,1b,1c,1d  really the same as   95% 1a,1b, 95% 1b,1c, 95% 1b,1d ?

95% 1a,1b,1c,1d is translated internally in FET as 95% 1a,1b, 1a,1c, 1a,1d, 1b,1c, 1b,1d, 1c,1d (add each pair of activities in a new min days constraint). So, considering the other 100%, it should be the same. I hope I am not mistaking.

Quote
Is 95% the right weight, if it is regardless, if 1b occurs in a double periode or as a single period?

Then you should add no constraint (if you don't care if the activities are consecutive if in the same day), or add a constraint with 0% and set consecutive if same day = true (which I think is your case).
Title: Re: min/ max double periods
Post by: lebwoski on February 11, 2014, 10:47:21 AM
Thank you, this works for me
Title: Re: min/ max double periods
Post by: guido55 on September 05, 2015, 07:16:33 AM
Hallo, it is the first time i use FET and have some problem to understand this language. I have the same problem, Math no more that 2 hours per day in a class. How do i prepare this bond? Thanks
Title: Re: min/ max double periods
Post by: Volker Dirr on September 05, 2015, 08:23:09 AM
Hallo Guido,
did you already read chapter "Add an activity" in the manual?
See:
http://www.timetabling.de/manual/FET-manual.en.html#id_15
Title: Re: min/ max double periods
Post by: guido55 on September 05, 2015, 08:51:09 PM
I have read it but i do not understand how to solve my problem. Really this is the question: the teacher of Math has 8 hours in a class divided in 5 days, and she cannot have more than 2 per day, thus the hours should be 2+2+2+1+1. I am not able to create this bond, may you explain all the passages to do it. Thank you.
Title: Re: min/ max double periods
Post by: Liviu Lalescu on September 05, 2015, 09:29:26 PM
If the activity must be 2+2+2+1+1, you can add a larger activity split into 5 components with durations 2,2,2,1,1, min 1 days 100%. This is the simple case.

If you can allow either of 2+2+2+1+1 or 2+2+2+2, this is more complicated. Add an activity split into 2,2,2,1,1, no min days constraints. Then either add an activity tag to these 5 (sub)activities and say max activity tags per day for students/teachers = 2, or add more min 1 days with 100%: between each pair (2,2) and between each pair (2,1) (3+6 constraints = 9 constraints - a lot of work).

Or: add an activity split into 4, min days = 1 100%, 2,2,2,1. Then add a single activity, duration 1. Then 3 constraints min 1 days 100% between each 2 and the single activity with 1.
Title: Re: min/ max double periods
Post by: Volker Dirr on September 06, 2015, 09:03:47 AM
Quote from: Liviu Lalescu on September 05, 2015, 09:29:26 PMIf you can allow either of 2+2+2+1+1 or 2+2+2+2, this is more complicated. Add an activity split into 2,2,2,1,1, no min days constraints.

It's easy (to enter the data; but it will be a bit slower to generate then Livius variant) if he has got a 5 days week. Just add a 1+1+1+1+1+1+1+1 with weight 0% and consecutive flag.
Title: Re: min/ max double periods
Post by: Liviu Lalescu on September 06, 2015, 09:11:11 AM
Quote from: Volker Dirr on September 06, 2015, 09:03:47 AM
Quote from: Liviu Lalescu on September 05, 2015, 09:29:26 PMIf you can allow either of 2+2+2+1+1 or 2+2+2+2, this is more complicated. Add an activity split into 2,2,2,1,1, no min days constraints.

It's easy (to enter the data; but it will be a bit slower to generate then Livius variant) if he has got a 5 days week. Just add a 1+1+1+1+1+1+1+1 with weight 0% and consecutive flag.

Oh yes, I forgot. I think it should have nearly the same speed of generation. The explanation why it works if that FET will not place 3 activities in the same day if consecutive if same day is selected.