OpenChess

Greetings to all:

Those who frequent TalkChess already know about my little perft(13) project; I'd thought I'd join and post here for the rest of you.

Perft(13) is the number of distinct move paths of length 13 ply from the initial position. Paul Byrne has already posted a number for this; what I'm doing is a calculation providing an answer which will have the supporting 20 draft 12 values (1st level proof) and the 400 draft 11 values (2nd level proof). My calculation was started almost six months ago in early August 2011.

After 25 weeks and 4 days, the run has produced 136 (34%) of the 400 draft 11 records. I have posted these results on the net so that others with an interest may verify my work.

http://dl.dropbox.com/u/31633927/Perft/Perft13/draft11

You are dedicated, thanks!

The first estimates for total running time were in the 5 to 10 month range; it now looks like 11 to 12 months total.

The program doing the work is my chess program Symbolic modified to use a 120 bit length hash, a 64 bit increase over the standard version. The change was made because trial runs with perft(12) calculations produced an occasional false positive transposition table match.

A program designed specifically to calculate perft(n) would surely be much faster.

Eight of the twenty draft 12 subtotals have been calculated. As with the draft 11 results, at

http://dl.dropbox.com/u/31633927/Perft/Perft13/draft11

these draft 12 records have also been posted on the net:

http://dl.dropbox.com/u/31633927/Perft/Perft13/draft12

The projected completion date is currently June 20, 2012, some 320 days since the start of the occasionally interrupted run.

The estimated total elapsed time easily beats that of a run I made in 1994 which took 87 days to calculate the KBNKN DTM tablebase on a creaky old 33 MHz 486DX machine.

Perft(12) done in mid 2011 took 14 days on the same 3.4 GHz Core i7 box which is now engaged with perft(13).

Perft(7) done circa 1989 took 36 hours on a 16 MHz 68020. With better algorithms and much better hardware, perft(7) today takes only ten seconds or so.