Closed vondele closed 9 months ago
- positions at all game plies between 1 and 16
Just a tiny correction. The earliest game ply I could find is 2, e.g. for the position rnbqkbnr/p1pppppp/8/1p6/3P4/8/PPP1PPPP/RNBQKBNR w KQkq - 0 2
.
Edit: Here the complete list of frequencies.
game ply 2: 5 times
game ply 3: 47 times
game ply 4: 642 times
game ply 5: 3454 times
game ply 6: 12996 times
game ply 7: 29984 times
game ply 8: 60510 times
game ply 9: 99575 times
game ply 10: 156793 times
game ply 11: 217136 times
game ply 12: 288550 times
game ply 13: 353868 times
game ply 14: 420058 times
game ply 15: 470702 times
game ply 16: 517716 times
A new book derived from Lichess games, with a model draw rate between 48% and 52%
It attempts to address the following points, relative to the currently used book:
The construction process involved
1) Parsing all 15B lichess games in the database https://database.lichess.org/ for the period Jan - Sept 2023. Extract from these the popular positions, i.e. seen at least twice, within the first 16 plies played, exploring newly added games to at most 8 previously unseen plies.
fastpopular as available at https://github.com/vondele/fastpopular
2) Score all these 296M games with a modified stockfish, based on master, that analyses positions up to a depth 24, for as long as the draw rate is predicted (UCI_ShowWDL) near 50%. Positions will be analysed to low depth if the draw rate is very different from 50% at low depth. From these scored positions, extract those with a draw rate in the range 48 - 52% That modified branch is available at https://github.com/vondele/Stockfish/tree/createUHO
Short initial testing at STC shows the draw rate is, as expected, close to 50% for self-play games: