+swiss+

[pilun]

So I ran a BBO Swiss Pairs on Saturday, 16 pairs, 6 x 8 boards. (Whether this format is "correct" is irrelevant)

Everyone out here hates Danish - mainly because of the repeats - so I was pleased to see the +swiss+ hack was available, so I tried it.

There was good and bad news.

 

For most of the field, there were no repeats. Great!

However, the bottom two pairs played each in the last THREE rounds. So what went wrong?

 

In a Danish, 1st plays 2nd, 3rd plays 4th throughout.

In a true Swiss, 1st plays the highest team it has not yet played and the algorithm proceeds through the field. However, to stop repeats, the algorithm also works bottom up through the bottom x teams.

 

What appears to happen with +swiss+ is top-down only, so the bottom teams get stuffed. (Serves them right for playing so badly or being so weak?) Is it so hard to implement a Swiss with no repeats?

 

Note that this is only my guess at what happens. Maybe I simply got the syntax wrong.

[paulg]

Unfortunately this is the expected (and documented) behaviour. I agree that a more sophisticated matching algorithm would be far more popular with the players.

[peterb001]

Hi. This is the first I have heard of this option. Can you point me at any write up of this facility, please? Thanks.

[paulg]

• +swiss+ avoids re-matches in your Swiss Pairs tournaments. Without the +swiss+ description string, Swiss Pairs on BBO run Danish style, with highest scoring pairs meeting each other multiple times.