Round Robin Tournament Scheduling

Schedules - You must register to Post and Download => Requests => Topic started by: cunms on January 14, 2013, 01:23:39 PM

Title: 17 teams each play 10 games
Post by: cunms on January 14, 2013, 01:23:39 PM
This should be simple shouldn't it? Need to schedule 12 games for 17 teams. Obviously, each team will not play every other team, and I want to avoid playing any team more than one. Thanks for your advice. I'm running out of graph paper. :-/

edit: we are playing 12 games not 10.
Title: Re: 17 teams each play 10 games
Post by: Ian Wakeling on January 15, 2013, 02:27:12 AM
Use the 'schedules' link near the top of this page and then dial up the cyclic schedule for 18 players.  You can convert this into a suitable schedule by deleting the 'Match 1' column and also deleting the last 5 rounds.  Finally subtract 1 from all the player numbers to map 2 to 18 back to 1 to 17.  Some players will have one more game than others, but there is no way to avoid that if you want to play less than the full 17 rounds.
Title: Re: 17 teams each play 10 games
Post by: wbport on January 15, 2013, 07:27:33 AM
You also might want to consider a swiss system or swiss guided round robin.  If the teams have some kind of rankings or seedings, pair 1-10, 2-11, etc. with team 9 getting the initial bye.  Use a round robin table (http://home.comcast.net/~wporter211/realsite/chess_etc/rrpair.htm) for 18 players and assign pairing numbers randomly to the top half, but give the lower half numbers which force the above pairings in the first round.  Pick round numbers in the RR table that force the most number of perfect scores to meet.  Once you have one or fewer teams with perfect scores, choose random unplayed rounds.
Title: Re: 17 teams each play 10 games
Post by: cunms on January 17, 2013, 01:06:06 AM
Thanks for the replies. Unfortunately, I had worked something out the hard way before I saw them. Tell me what you think if you don't mind. I've never done this so I might be missing something.

I divided the group into two divisions of 9 that each play a full round robin. This gives each team 8 games in division. I then gave each team four games against teams from the other division:
Team 1 plays 10,11,12,13
Team 2 plays 11,12,13,14
Team 3 plays 12,13,14,15
Team 4 plays 13,14,15,16 (this completes adding 4 games to team 13)
Team 5 plays 14,15,16,17 (this completes adding 4 games to team 14)
Team 6 plays 15,16,17,10 (this completes adding 4 games to team 15)
Team 7 plays 16,17,10,11 (this completes adding 4 games to team 16)
Team 8 plays 17,10,11,12 (this completes adding 4 games to team 17)
Title: Re: 17 teams each play 10 games
Post by: Ian Wakeling on January 17, 2013, 03:42:27 AM
I am confused by the number of teams.  There is no team 9 in your list of extra games, and if you really have 17 teams then it is not possible to divide them into two equal sized divisions.  Also note that listing the extra games only solves part of the problem, presumably you would like to play then in rounds of 4 simultaneous games.
Title: Re: 17 teams each play 10 games
Post by: cunms on January 17, 2013, 04:38:28 PM
Oh boy... I'm a bad newbie. I totally forgot why I finally figured out how to do it. It is because we added an 18th team.   :-[

So correction to above post:
Team 6 plays 15,16,17,18 (this completes adding 4 games to team 15)
Team 7 plays 16,17,18,10 (this completes adding 4 games to team 16)
Team 8 plays 17,18,10,11 (this completes adding 4 games to team 17)
Team 9 plays 18,10,11,12 (this completes adding 4 games to team 18)