Round Robin Tournament Scheduling

Bridge for 20 couples meeting 7 times

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Norma Ridener(Guest)

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on: August 29, 2008, 02:09:32 PM
You did a superior job answering Judith's question about scheduling 24 couples playing once a month for seven months.

I need a similar answer for 20 couples playing once a month fo seven months (four couples at each site). The schedule I currently have has couples playing each other as many as three times.

Is it possible to minimize the number of times the same two couples meet?  Your help will be greatly appreciated!

Norma


Ian Wakeling

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Reply #1 on: August 30, 2008, 02:35:40 AM

Norma,

With seven rounds, each couple must meet with 21 other couples (3 per month) and so it must be the case that some couples meet more than once.

In the schedule below each couple meets with 17 of the other couples once and with the remaining 2 couples twice.


   5   2  17   7
  15  19   1   6
   3  18  14   9
   4  10   8  16
  13  20  11  12

   5   9   2  18
   3   6  13  16
  10   1  12  14
   8  19  11   7
   4  17  20  15

   9   3  11   4
  12  16  19   2
   5  10   6  17
  13  15  14   8
  18  20   7   1

   2   7  10  13
   5   3  12  15
  18  19   4  14
   9   8   6  20
  17  16  11   1

   2   6  11  14
  10  20   3  19
   4  13   1   5
  18   8  17  12
  16  15   7   9

   2   8   1   3
  13  19   9  17
  10  11  15  18
  14  20  16   5
   4   6  12   7

   6  18  16  13
  20   4  15   2
  10  12   9   1
  19   8   5  11
  17  14   3   7


The couples who meet twice are


1 : 10 12
2 :  5  7
3 :  9 14
4 : 15 20
5 :  2 17
6 : 13 16
7 :  2 17
8 : 11 19
9 :  3 18
10:  1 12
11:  8 19
12:  1 10
13:  6 16
14:  3 18
15:  4 20
16:  6 13
17:  5  7
18:  9 14
19:  8 11
20:  4 15


So for example couple 7 meets twice with couples 2 and 17, but only once with all other couples.

Hope that helps.

Ian.


Norma  Ridener(Guest)

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Reply #2 on: September 02, 2008, 11:14:50 AM
Ian:

Thanks so much for figuring out the 20 couple round robin schedule.  It enabled me to type up quickly the schedule for the next year knowing that someone smarter than I knew what he was doing.

Keep the good work going!


Norma :) 8-) :-* :D ;D


mark_wayne

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Reply #3 on: August 17, 2010, 01:22:23 AM
 My wife needs your help. She & her friend are responsible for scheduling the 8 teams of 2 people each to play bridge over an 8 month period. There will be 2 hostesses each month hosting 3 additional teams to make up 2 tables of 4 players each. They wish to spread out the hosting so someone does not have to host 2 months in a row. The first numbers showing up on the list are the host teams.They wish that the same couple host December & May. Their desire is to have each team play together at least twice in the 8 month program. They wish to eleminate couples playing each other 2 times in a row if possible.
Help Please.
Mark Hochanadel
Omaha


rideners

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Reply #4 on: August 02, 2011, 12:57:30 PM
You did a superior job answering my question last year about scheduling 20 couples playing once a month for seven months.
 
It is harder to find bridge players.  Therefore, this year I need a similar answer for 16 couples playing once a month for seven months (four couples at each site).
 
Thank you!
 
Norma  :) :D ;D 8-)


Ian Wakeling

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Reply #5 on: August 03, 2011, 02:59:18 AM
Hi Norma,

Welcome back.

There is a schedule in thread "16 golfers, 4 groups over 12 rounds" that you could use.  If you play the first 7 rounds then everyone will meet different couples for the first 5 weeks and all the repeats (couples will see 6 of the other couples exactly twice) will occur in the weeks 6 and 7.

Hope that helps,

Ian.


rideners

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Reply #6 on: August 08, 2011, 10:19:35 PM
Thanks Ian for referring me to an earlier solution for 16 couples playing bridge 7 times.  You do GREAT WORK!

Norma