Somebody told me once that SwisSys avoids pairing players with the same last name, whenever feasible, regardless of any “family” settings. If that’s true, then, bingo.
Bill Smythe
Based on the number of times I’ve seen SwissSys pair family members with the same surname, I’d have to say that sounds apocryphal.
SwissSys has pair restriction options for Federation/club, team, city, state.
In recent versions it only does this in the first round, and it asks whether you want to avoid pairing family members. I always say no, because if they’re really family members who shouldn’t be paired I handle it myself with zip code or team pairings.
Regarding the original question, I ran into a similar problem myself at this year’s New Hampshire Open. I was running an older version, 8.894, but I’ve just replicated the problem with 8.9. It was a five round tournament, and these were the standings and color histories going into the last round:
2367 3 - W B W
2123 3 W B W -
2113 3 B W B W
2258 2.5 B - W B
2000 2.5 - W B W
2041 2 - B W B
2003 2 W B W B
1928 2 B W W B
1816 2 - B W B
1978 1.5 B W B -
1953 1.5 W - B W
1990 0.5 W B B W
2367 has played 2258, 2041, 1928
2123 has played 2000, 1978, 1928
2113 has played 2258, 2041, 1953, 1816
2258 has played 2367, 2113, 1990
2000 has played 2123, 2003, 1816
2041 has played 2367, 2113, 1953
2003 has played 2000, 1990, 1978, 1928
1928 has played 2367, 2123, 2003, 1953
1816 has played 2113, 2000, 1990
1978 has played 2123, 2003, 1990
1953 has played 2113, 2041, 1928
1990 has played 2258, 2003, 1978, 1816
SwissSys pairings were:
2123 vs. 2367
2113 vs. 2000
2041 vs. 2258
1816 vs. 2003
1978 vs. 1928
1990 vs. 1953
This gives 2123 three Whites and one Black and gives 2258 three Blacks and one White. I changed the pairings to:
2113 vs. 2367
2258 vs. 2123
2041 vs. 2000
1816 vs. 2003
1978 vs. 1928
1990 vs. 1953
Granted, that’s sort of a messy thing to pair since you have a cascading set of floats because the top score group has three and just about all the others have an even number, but that just looks weird. Not only do the computer pairings get the colors wrong, but it upfloats the 2000 rather than 2258 (a 258 point switch) in order to make the colors worse. Could you PM me a cross table so I can see how WinTD handles it?
Does SwissSys have a top-down setting for pairings? It really looks like simple top-down pairings were used instead of look-ahead pairings.
There is no setting for top-down pairings. There is an option for “In-depth searches” which is selected by default and which I haven’t changed.
I reported the problem to Thad Suits and got a reply, which I responded to. When Thad has a definitive answer about why SwissSys produced the pairings that it did and whether he considers it to be a bug I’ll ask for his permission to post it here.
If somehow the swap of the 2123 with the 2113 is missed (which I see as a 10 point transposition, but might be looked at as an interchange, though even then it would be fine) , then everything else is basically forced as Jeff says. (WinTD agrees with Bob’s pairings).
I never said the fact that it was hypothetical wasn’t important info.
I take it from the rather pointless post that you were never really serious about getting an answer.
If Mr. Smith used NWSRS ratings, then what difference would it make?? Darts would be a good alternative.
Rob Jones
See my new topic Dubov System Swiss pairings for more discussion about the pairings in this tournament.