It has been about 3 months now since V11.75, and Ethereal is making quick
progress due to massive contributions from Alayan, as well as the utility
of OpenBench and the tuning mechanisms built into Ethereal.
These patches include a wide range of improvements, including endgame scaling
gains, additional search techniques, new contempt options, many speedups
particularly for Linux systems, new evaluation terms covering a wide variety
of concepts, tons of tuning to search and evaluation, and much more.
A big thanks to all of those who have donated CPU time to OpenBench.
Those users can be found here http://chess.grantnet.us/users/
Binaries for Windows {PEXT/POPCNT/NOPOPCNT} & for Android {ARMV7/ARMV8}
Ethereal 12.00 vs Ethereal 11.75
ELO | 24.06 +- 3.03 (95%)
Fixed | 60.0+0.6s Threads=1 Hash=64MB
Games | N: 15751 W: 3018 L: 1929 D: 10804
http://chess.grantnet.us/viewTest/4801/
Ethereal 12.00 vs Ethereal 11.75
ELO | 29.63 +- 3.77 (95%)
Fixed | 20.0+0.2s Threads=8 Hash=256MB
Games | N: 10016 W: 1979 L: 1127 D: 6910
http://chess.grantnet.us/viewTest/4803/
A quick summary of the changes, one patch at a time:
Patches denoted with an "*" are by Alayan, those with "&" are by Weiss
author Terje, and those with "+" are from Github User Skiminki.
Code: Select all
* 11.76 Score Knights/Rooks based on how open the position
is. Openness is a function of the number of open
files as well as the number of rammed pawns.
11.77 Moved Closedness to its own function for a speedup.
* 11.78 Penalize hanging pieces threatened by a King.
& 11.79 Implement Multi-Cut Pruning based on attempts to prove
a move to be Singular.
& 11.80 Remove the redundant attackersToSquare() function.
* 11.81 Simplify away the Razoring in the main search routine.
* 11.82 Add rough elo estimates for various search techniques.
* 11.83 Apply an extra penalty for Passers that are stacked.
11.84 Fix a small white/black mirroring issue in Passed Stack
Pawn evaluation introduced with patch 11.83.
* 11.85 Penalize mutually attacked squares that are poorly defended.
* 11.86 Tune the evaluation terms added in patch 11.85
* 11.87 Bonus for Bishops on an open, long, diagonal controlling
some of the central squares, a la Stockfish.
* 11.88 Penalize knights that are far from both of the Kings.
* 11.89 Increase the Static Exchange Evaluation Pruning depth to 9
* 11.90 Evaluate Backwards pawns by their ranks. Adjust the Pawn
piece-square table to account for this change.
* 11.91 Apply an early game bonus having sole control over central
squares. Taper off this bonus as the position simplifies.
+ 11.92 Prefetch Transposition Table entries as early as possible.
* 11.93 Introduce Draw Contempt and Complexity Contempt.
* 11.94 Scale down the eval for a lone queen versus multiple other
minors and or majors, when the queen is given the advantage.
11.95 Scale up lone minor/rook vs lone minor/rook when there is
a difference of three or more pawns between the players.
& 11.96 Resolve fail-highs with progressively shallower searches.
* 11.97 When evaluating King Safety, exclude attacks to squares that
are twice protected by our pawns. Idea from Vizvezdenec.
* 11.98 Move 'space' evaluation terms to their own function.
Add Alayan to the authors output. Fix tuner and UCI options.
+ 11.99 Advise the Kernal to use Transparent Huge Pages.
* 12.00 Add a small variation to drawn evaluations to avoid potential
blindness to 3-fold repetitions.
