Round Robin Tournament Scheduling

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Requests / 12 Teams with 3 teams playing at a time
« Last post by mroucka on November 18, 2019, 09:40:11 AM »
I am a cross country coach and I am trying to schedule triangular (3 team) meets within our 12 team conference.  I want everyone to play every team at least once and no more than twice.  I would also like to have only 6 meets.
Requests / Re: 10 team round robin with 6 teams sharing 3 home venues
« Last post by Ian Wakeling on November 03, 2019, 10:20:43 AM »
I think the v5.1 spreadsheet will solve the problem.  Just ask for 10 teams in home/away format.   Then A & B,  C & D, and E & F are the pairs that share venues.  Image of the output is attached (you need to log in to see this).

Requests / 10 team round robin with 6 teams sharing 3 home venues
« Last post by snowyguy on November 03, 2019, 07:30:26 AM »
Hi Ian
Awesome effort but I'm trying to find a draw that will allow 6 teams out of the 10 sharing 3 home venues involved to alternate their home venues each week 
The other 4 teams have individual home venues

Thanks in advance for any help you can provide
Requests / Re: Bye round?
« Last post by Ian Wakeling on October 19, 2019, 06:24:56 AM »

I have been thinking about this some more and have programmed an algorithm along the lines that I outlined above.  What follows is for 12 players.  For goal (2) you have established that it is possible to have a schedule were pairs never share a bye together three times, so this should be a requirement, and then we should count the number of pairs (NP) that share a bye twice, and look for a schedule that minimizes this count.  In your example schedule I believe NP=12, although I did count them by hand, so it is possible I am off by a little.

After some experimentation I believe that if goal (1) must be achieved, then it is not possible to do better than NP=8. Here is an example schedule for the 4 byes and 9 rounds that also meets the no more than 4 games in a row requirement.

 10  5  2  1
 12  7 11  8
  3  4  1  9
  8  6 10 12
  7  5  2  3
  9 10 11  6
  1  4  7  8
 12  2  9  3
  4 11  6  5

The 8 repeated pairs are:

 1  4
 2  3
 2  5
 3  9
 6 10
 6 11
 7  8
 8 12
« Last post by johbri on October 17, 2019, 05:40:10 PM »
A sligth improvement. There are more rooms for improvement but I have no more time righth now.

« Last post by johbri on October 17, 2019, 05:21:42 PM »
A suggestion. This is the schedule for group A. Make exactly the same schedule for group B.
The men (in blue have names 1 to 8 ) and the women in pink have the numbers 1 to 8. 
So male 1 and 8 starts against woman 2 and 6. You could change the courts between rounds if you dont want player 8 to play at the same court all the time. There are 14 rounds per group but you can stop whenever you like. I am not an expert on this so perhaps you will get better advice from some of the other members. 

« Last post by Sebastian on October 16, 2019, 02:12:55 AM »
Greetings All. I need some help developing a tournament schedule that takes into consideration the following: 16 Men & 16 Women. Partners are drawn from a hat. From these 32 players, 16 are separated into the A-Group "Advanced Players" and 16 B-Group "Good Players".  Each original male/female pair plays each pair in their group. Midway into each match, the men change sides. Each player must therefore report his/her individual score to the scorekeeper at the end of each match. Four courts are available for our use from 8h30 to 15h30 - which would suggest that 8 games per match would be appropriate. Towards the end of the tournament, the winners of Group A and Group B play against each other so that there is an overall winner. How can I develop a results recording schedule that takes these points into consideration that is easy to understand for the score-keepers? Your assistance would be greatly appreciated. :)
Requests / Re: Bye round?
« Last post by johbri on October 14, 2019, 09:52:13 AM »
Thank you Ian for your clever advice. 

The tournament that I'm scheduling is padel. We play for 2-3 hours. I do think that having bye two times in a row is really bad so I think I would like to have the following rules:

1) No player should ever have two byes in a row. (Neccesary condition)

2) Among the possible solutions fullfilling 1) I would like the variation among which I share my bye we to 
be as large as possible.  Hence Ian's suggestion above would be optimal if it fullfilled requirement 1. 

I need to be able to do this for 9,10,11,12 players playing on two courts (8 playing 1,2,3 or four having a bye each round).  So perhaps the schedule that I did for 12 players above is close to optimal?

Requests / Re: Bye round?
« Last post by Ian Wakeling on October 14, 2019, 03:56:59 AM »
I doubt there is any systematic way to achieve what you want.  The fundamental problem is that goal (1) and goal (2) are mutually incompatible. Goal (1) can be achieved by repeating rounds 1 to 3 above three times; then everyone will have their byes exactly 3 rounds apart, however the schedule is optimally bad for (2), as you always have a bye with the same three players.

There is a way to optimize (2) as follows:

   2  6  8  1
   3  4  9  2
   1  5  7  3
   5 12  9  6
   6 10  7  4
   4 11  8  5
  10  9  1 11
  11  7  2 12
  12  8  3 10

where the 9 people a player shares a bye with are all different. But this comes at a price, any pair of the blocks of 4 above have exactly one player in common, so no matter how the rows are ordered there will be 8 occasions where a player has two byes in a row.

What you are asking for is a trade off between the two goals, and that suggest some sort of search algorithm that gives differential weights to (1) and (2).

For me, living with the repeated byes is the better option, since if you have optimal mixing within the byes, then you also have optimal mixing among the groups of 8 who meet together.
Requests / Re: Bye round?
« Last post by johbri on October 11, 2019, 08:46:43 AM »
Thanks for your advice. In the schedule below there are 12 players and four have a bye each round. My goal is to:
1. Get the byes as evenly spread per person as possible. You should e.g. not have two byes in a row.
2. You should have as much variation regarding which people you share your bye with. Now player 1 and 2 have the same bye twice but I managed to not let anytwo players have the same bye three times. (But I don't think my schedule is optimal. There should be possible to have more variation.)
3. No player plays four games in a row (related to goal 1 above).
I thought there should be a systematic way to place the byes but perhaps not. 
(In my tournament I rank the eight players before each round and let rank 1+4 play 2+3 and rank 5+8 play 6+7 (according to there internal ranking). Hence there is no need to make sure that everyone plays everyone. My goal is to get as even games as possible in each round.)