Round Robin Tournament Scheduling

### 24 Player Doubles Pickleball League - Round Robin

roller55 · 6 · 5565

#### roller55

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on: October 02, 2014, 10:44:44 PM
Trying to put together a 24 player round robin where each player plays only one match with each of the other 23 players and hopefully never plays against the same combination of partners more then once.  The 4 players assigned to each court each week will play one match with each of the other 3 players as their partner.

Someone on the site provided me with a 16 players schedule back in July and now we've added players for the next league.  So, please help.  This is way beyond my capabilities to schedule.

#### Ian Wakeling

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Reply #1 on: October 03, 2014, 02:27:27 AM
It all works nicely with 16, since there are 15 other players, and 15 is divisible by 3, where 3 is the number of other players that you meet each round.   It should now be clear that 24 players is going to be a problem, since 23 is not divisible.   However, it is possible to play 7 rounds and for everyone to have 21 different partners, for an example see the schedule here look just below "24 golfers can play in foursomes for 7 days".  Would that work?   You could possibly have a round of singles at the end to mop up the players who have not met in the first 7 rounds.  The players would need to meet in 8 groups of 3 as follows:

AIQ
BJR
CKS
DLT
EMU
FNV
GOW
HPX

then you would play the 3 possible singles matches within each group, so  A v I,  A v Q and I v Q for the first group.

Finally note that there is an error in the schedule I linked to above, the first foursome for Day 6 has an 'E' that should in fact be a 'G'.   I will email the site, so it's possible it will be corrected by the time you read this.
« Last Edit: October 03, 2014, 09:17:03 AM by Ian »

#### roller55

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Reply #2 on: October 03, 2014, 07:09:08 AM
The schedule below is for 8 groups of 3.  What is needed is 6 groups of 4 each night.  The league is a doubles league, but scoring will be kept for each individual.  Example of 1st week:
Court 1 ABCD  AB vs CD, then AC vs DB, then AD vs BC
Court 2 EFGH   EF vs GH, then EG vs FH, then EH vs FG
Court 3 IJKL     Same round robin format
etc for 6 groups on 6 courts

So, what is needed is for each player to never player with the same player against the same opposition more then once in the season.

I get through the first 3 weeks without any duplicate matches, but then it falls apart on me and I have duplicate matches.

Back in July, you gave me a table for 16 players set up this way and it worked great, but I still can't apply the concept to the greater number of players.

#### Ian Wakeling

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Reply #3 on: October 03, 2014, 09:14:42 AM
Please re-read my message above.  In particular follow the link in it to Ed Pegg's Social Golfer page to find a schedule suitable for 6 groups of 4 for 7 nights.  The 8 groups of 3 is something you might consider for  night 8.

#### roller55

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Reply #4 on: October 03, 2014, 10:29:19 PM
I may not be following correctly, but I believe that this schedule is what you were referencing.  It doesn't fully fit what we're trying to accomplish.  Since each match will be played in doubles format, we never want to repeat any of the players in a grouping.  Quickly looking at the below, Player A will play with and against Player E on Day 4 and Day 6.  Player A never plays in a group with Player I, so they will never play with or against each other.  We want every player to team with every other player for 1 game over the course of the season and against every other possible combination of players.  From the 16 player schedule you gave me back in July, I know the number of weeks becomes excessive, but what we did was play 1 complete scheduling cycle.   I couldn't find my previous posting, maybe you can and see what you gave me back then.

Day1 ABKU IJSE QRCM DGFX HLNO PTVW
Day2 ACLV IKTF QSDN EHGR BMOP JUWX
Day3 ADMW ILUG QTEO FBHS CJNP KRVX
Day4 AENX IMVH QUFP GCBT DJKO LRSW
Day5 AFOR INWB QVGJ HDCU EKLP MSTX
Day6 [highlight]AEPS[/highlight] IOXC QWHK BEDV FJLM NRTU
Day7 AHJT IPRD QXBL CFEW GKMN OSUV
« Last Edit: October 04, 2014, 01:36:32 AM by Ian »

#### Ian Wakeling

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Reply #5 on: October 04, 2014, 01:35:59 AM
This is the schedule I was recommending.  What you have been trying to accomplish is mathematically impossible and this schedule is the next best thing. Or rather, it will be the next best thing, after the error in Day 6 has been corrected, as [highlight]AEPS[/highlight] should read AGPS.  If you do this, then there will be no repeats of any player in a grouping.  Every player has two other players they do not meet in a group.  For player A this is I and Q.  Also note that player I does not meet Q.  All the pairs that do not meet can be read off from the 8 groups of 3 in Reply #1 above, hence my suggestion that you could have them meet in threes for singles play on day 8.

If you are logged in and click on you own username above,  then you will see an option at the bottom to show the last 5 or 10 posts.  Use this if you want to find your old posts.
« Last Edit: October 04, 2014, 05:11:25 AM by Ian »