Mixed round robin

[bfrancis]

Hi,

I am the scheduler for a Mixed curling league, with 30 teams organized into 5 divisions. We have 3 sheets available and 5 draws per weekend. I've been creating schedules by hand so that teams play once in each of the 5 available draws (2 on Friday and 3 on Sunday). To simplify things, all teams in the same division play at the same time.

I've now been asked to really mix things up, so that different divisions play on the 3 sheets at each draw.

I would appreciate any ideas on how I should go about doing this!

Thanks,
Brian

[Ian Wakeling]

Hi Brian,

I think you can probably rearrange the current schedule, but to do this you need a second plan that assigns each sheet at each draw to one of the 5 divisions.  If you use the following:

Week Day S1 S2 S3
  1  Fri  1  5  3
  1  Fri  5  4  2
  1  Sun  1  4  3
  1  Sun  2  3  4
  1  Sun  2  5  1
  2  Fri  4  2  3
  2  Fri  5  1  2
  2  Sun  3  1  4
  2  Sun  3  4  5
  2  Sun  1  2  5
  3  Fri  2  3  1
  3  Fri  4  1  5
  3  Sun  2  5  3
  3  Sun  3  4  5
  3  Sun  4  1  2
  4  Fri  5  3  4
  4  Fri  2  4  1
  4  Sun  1  3  5
  4  Sun  5  2  4
  4  Sun  3  1  2
  5  Fri  3  5  1
  5  Fri  4  3  2
  5  Sun  1  2  4
  5  Sun  5  2  3
  5  Sun  4  5  1

This has the following properties:

Each division has:
6 slots on a Friday
9 slots on a Sunday
5 slots on each sheet
3 slots per week

Also:
3 different divisions participate in every draw, and
pairs of divisions play next to each other in the same draw either 7 or 8 times (the optimal mixing that you requested).

Would that work for you,

Ian.

[bfrancis]

Absolutely marvelous!

Out of interest, how did you create the 3 team/row schedule? Is there an Excel macro for that?

Thank you very much Ian.

Brian.

[Ian Wakeling]

I am sorry, I don't have any macro or other software that could generate the plan above.   I used some mathematical software to get half way there, and then balanced the Fridays and Sundays by hand.

Ian.