Doubles schedule for 12 players,

[Monica]

(Sorry in advance - my English is not the best...)

I need a schedule for a tennis tournament. 12 players, 3 courts, 4 rounds of doubles. 
I'm trying to optimize it so that every player only plays once with OR against any other player. If that is not possible than only once with another player and only once against that other player. So that every player plays with/against as many different players as possible.

I already have been trying for days but with no success... hope you can help.

[Ian Wakeling]

What you are asking is not possible - there needs to be 16 players or more if you want no pair of players to be on court together more than once.

I think the schedule below is the best that you can do.  There are 18 pairs of players who meet twice, and 12 pairs who never play together.

 (12  9 v  1  4)  ( 6  3 v  8 11)  ( 2  5 v 10  7)
 ( 2  4 v  5  6)  ( 3 12 v  7  9)  (10  8 v  1 11)
 ( 8  6 v 10  9)  ( 4 11 v  7  2)  ( 1 12 v  5  3)
 (11  2 v  9  1)  ( 3  8 v  4  5)  (12  7 v  6 10)

[Monica]

Thanks so much Ian, great help!

[MCR426]

What you are asking is not possible - there needs to be 16 players or more if you want no pair of players to be on court together more than once.

I think the schedule below is the best that you can do.  There are 18 pairs of players who meet twice, and 12 pairs who never play together.

 (12  9 v  1  4)  ( 6  3 v  8 11)  ( 2  5 v 10  7)
 ( 2  4 v  5  6)  ( 3 12 v  7  9)  (10  8 v  1 11)
 ( 8  6 v 10  9)  ( 4 11 v  7  2)  ( 1 12 v  5  3)
 (11  2 v  9  1)  ( 3  8 v  4  5)  (12  7 v  6 10)

Just discovered this schedule and it will work GREAT for me....but can you please add two more rounds?  THANK YOU IN ADVANCE!!

[Ian Wakeling]

Here is a six round schedule - there are three pairs of players who meet three times (4,7) (5,6) & (9,11), other wise all partnerships are different, and players play against all others once or twice.

( 1  2 v  5 12)  ( 9  6 v 11  8)  (10  4 v  7  3)
(12  2 v 10 11)  ( 5  6 v  3  4)  ( 7  1 v  9  8)
( 9 10 v  6  2)  ( 8 12 v  3  5)  (11  1 v  4  7)
(10 12 v  8  4)  ( 2  5 v  7  6)  ( 9  1 v 11  3)
( 7  9 v  4 12)  (10  6 v  1  5)  (11  2 v  3  8)
( 6  3 v 12  7)  ( 8  2 v  1  4)  ( 5 10 v 11  9)