Round Robin Tournament Scheduling

Co-ed Volleyball Triples

ndodge · 3 · 4140

ndodge

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on: June 24, 2015, 09:40:25 PM
I'm wanting to do co-ed volleyball triples and have figured out reasonable formats for most combinations of players that I might expect but there are a couple combinations for which I can't seem to figure out something reasonable by hand.  

One is when I have 3 women (call them a, b, c) and 6 men (call them 1-6) playing a set of games on 1 court.  I'd like to do 9 rounds, with 1 woman and 2 men sitting each round, with teams of wmm vs wmm each round.  Then each player would get 6 games and sit 3 times.  I'd like something reasonably balanced-it'd be nice if the men were both with and against each woman twice and the men with each other man 1 or 2 times.  I'm ok wit the men vs men not being perfectly balanced, but would be nice if that was as balanced as possible. I'll assume that the women can just play out the 3 possible matchups of woman vs woman 3 times each.  I'd also like each team combination to appear only once (eg 12a would be a team at most once).

The other scenario is when I have 4 women and 5 men, but I have to think about that one some more, about what combinations of men vs women I would like (probably need some combination of mmw vs mmw, wwm vs wwm, and wwm vs mmw).  Again, each player playing 6 and sitting 3 times would be nice.

Thanks,
Nathan


Ian Wakeling

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Reply #1 on: June 28, 2015, 04:02:04 AM
Nathan,

I think it may be impossible to come up with something reasonable as the scenarios you are considering are asymmetric.  For example think about forming teams of 3 when there are 3 women and 6 men.  Any man has a pool of 8 possible players they can play WITH, but the women have a pool of only 6 possible players.

So my suggestion is to modify the format slightly to introduce the missing symmetry.  Consider dividing your 9 players into 3 groups, 1 to 3, 4 to 6, and 7 to 9. Now the extra condition on the tournament is that all teams of 3 players must consist of exactly one player from each group. This solves the problem mentioned above, since now everybody has exactly 6 possible team partners, and they can have a tournament along the lines you suggest where each player:

(1) has 6 games and 3 byes
(2) plays WITH the 6 players from the other two groups exactly twice.
(3) plays AGAINST the 6 players from the other two groups exactly twice.
(4) plays AGAINST the 2 other players from their own group exactly three times.

Here is an example of a schedule that meets the conditions above:

 round     on court       sit out
    1   (1 4 7 v 2 5 9)   (3 6 8)
    2   (2 5 8 v 3 6 7)   (1 4 9)
    3   (3 6 9 v 1 4 8)   (2 5 7)
    4   (8 1 6 v 7 2 4)   (3 5 9)
    5   (9 2 4 v 8 3 5)   (1 6 7)
    6   (7 3 5 v 9 1 6)   (2 4 8)
    7   (5 7 1 v 4 8 3)   (2 6 9)
    8   (6 8 2 v 5 9 1)   (3 4 7)
    9   (4 9 3 v 6 7 2)   (1 5 8)


I think you would use this schedule by assigning one group to be women, one group to be 3 highest ability men, and the third group to be the 3 lower ability men.

There are exactly 360 ways of making the schedule above, where all the teams of 3 are different and all 9 games are different!  Send me an email if you would like to see the alternatives.

Hope that helps,

Ian.
« Last Edit: June 28, 2015, 06:47:10 AM by Ian »


ndodge

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Reply #2 on: June 28, 2015, 12:36:22 PM
Thank you, Ian, I think I will try your idea sometime.  For my next event, we were not wanting to divide men into two different groups like that but I think I may try that in the future.  I did come up with a format by hand that is balanced enough for what we want, even though it isn't perfect.  Since I was able to get it somewhat close by hand, I think I may finally try some programmatic approaches sometime, as I used to be a programmer, to see if I can improve it.  My solution by hand has these properties:

Each man plays with four other men once and 1 man twice
Each woman plays with and against the other 2 women 3 times each
Men play against each other man 2 or 3 times, except for one case where two men oppose once
Women partner 4 men twice, 1 man once, and 1 man 3 times
Half the men partner each woman twice
The other men partner the women 1, 2, or 3 times, respectively
Women and men oppose 1 to 3 times, in most cases twice
Each person gets 6 games and 3 byes
No team of 3 plays more than once