| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: protonspring
Date: Thu May 10 15:46:32 2018 +0200 Timestamp: 1525959992 Consolidate pawn storm types Simplification: the Unopposed and Unblocked pawn storm types are mathematically similar enough to combine with no Elo loss. This reduces the pawn storm types to BlockedByPawn and UnBlocked. STC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 116869 W: 23549 L: 23605 D: 69715 Elo -0.17 http://tests.stockfishchess.org/tests/view/5af2def90ebc5968e6523f82 LTC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 39912 W: 6090 L: 5998 D: 27824 Elo +0.80 http://tests.stockfishchess.org/tests/view/5af3b2e20ebc5968e6524013 Closes https://github.com/official-stockfish/Stockfish/pull/1592 Bench: 5244314 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Stefan Geschwentner
Date: Thu May 10 12:28:18 2018 +0200 Timestamp: 1525948098 Tune null move pruning Use a lower stat score threshold of 22500. Failed yellow at STC after many games (~0.92 Elo): LLR: -2.96 (-2.94,2.94) [0.00,4.00] Total: 73978 W: 14947 L: 14834 D: 44197 Elo +0.53 http://tests.stockfishchess.org/tests/view/5af2deec0ebc5968e6523f80 But scales good and passed LTC: LLR: 2.96 (-2.94,2.94) [0.00,4.00] Total: 23147 W: 3453 L: 3237 D: 16457 Elo +3.24 http://tests.stockfishchess.org/tests/view/5af3cf820ebc5968e6524022 Closes https://github.com/official-stockfish/Stockfish/pull/1591 Bench: 4777674 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: candirufish
Date: Wed May 9 09:22:11 2018 +0200 Timestamp: 1525850531 Tuned some pawns and evaluation constants Tuned values in pawns.cpp and evaluate.cpp after a SPSA session: 419k games 60sec 600nodetime. We have adjusted the PassedRank[] output of the SPSA session to keep increasing values with rank, and PassedFile[] output to keep the West <–> East symmetry of the evaluation. STC: LLR: 2.95 (-2.94,2.94) [0.00,4.00] Total: 58948 W: 12431 L: 12046 D: 34471 Elo +2.27 http://tests.stockfishchess.org/tests/view/5af2302f0ebc5968e6523f0a LTC: LLR: 2.96 (-2.94,2.94) [0.00,4.00] Total: 22211 W: 3468 L: 3251 D: 15492 Elo +3.39 http://tests.stockfishchess.org/tests/view/5af264c80ebc5968e6523f1a See https://github.com/official-stockfish/Stockfish/pull/1587 and https://github.com/official-stockfish/Stockfish/pull/1590 bench: 4437531 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Joost VandeVondele
Date: Wed May 9 01:42:34 2018 +0200 Timestamp: 1525822954 Remove goto, limit skipping to NMP This patch simplifies the control flow in search(), removing an if and a goto. A side effect of the patch is that Stockfish is now a little bit more selective at low depths, because we allow razoring, futility pruning and probcut pruning after a null move. passed STC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 32035 W: 6523 L: 6422 D: 19090 Elo +1.10 http://tests.stockfishchess.org/tests/view/5af142ca0ebc597fb3d39bb6 passed LTC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 41431 W: 6187 L: 6097 D: 29147 Elo +0.75 http://tests.stockfishchess.org/tests/view/5af148770ebc597fb3d39bc1 Ideas for further work: • Use the nodes credit opened by the patch (the increased selectivity) to try somewhat higher razoring, futility or probcut margins at [0..4]. Bench: 4855031 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Stefan Geschwentner
Date: Tue May 8 23:31:55 2018 +0200 Timestamp: 1525815115 Tweak null move pruning conditions Allow null move pruning only if last stat score < 30000. Passed STC: LLR: 2.95 (-2.94,2.94) [0.00,5.00] Total: 12653 W: 2641 L: 2454 D: 7558 Elo +5.14 http://tests.stockfishchess.org/tests/view/5af1d8830ebc5968e6523edb Passed LTC: LLR: 2.97 (-2.94,2.94) [0.00,5.00] Total: 19782 W: 3072 L: 2878 D: 13832 Elo +3.41 http://tests.stockfishchess.org/tests/view/5af1ee8c0ebc5968e6523ee4 Ideas for further work: • Tune the stat score threshold. • Try depth based stat score threshold. • Try stat score condition for other prunings. Closes https://github.com/official-stockfish/Stockfish/pull/1589 Bench: 5088156 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Alain SAVARD
Date: Tue May 8 11:14:43 2018 +0200 Timestamp: 1525770883 Drop the lever condition for backwards We can view the patch version as adding some "undermining bonus" for level pawns, when the defending side can not easily avoid the exchange by advancing her pawn. • Case 1) White b2,c3, Black a3,b3: Black is breaking through, b2 deserves a penalty • Case 2) White b2,c3, Black a3,c4: if b2xa3 then White ends up with a weak pawn on a3 and probably a weak pawn on c3 too. In either case, White can still not safely play b2-b3 and make a phalanx with c3, which is the essence of a backward pawn definition. Passed STC in SPRT[0, 4]: LLR: -2.96 (-2.94,2.94) [0.00,4.00] Total: 131169 W: 26523 L: 26199 D: 78447 Elo +0.86 http://tests.stockfishchess.org/tests/view/5aefa4d50ebc5902a409a151 ELO 1.19 [-0.38,2.88] (95%) Passed LTC in SPRT[-3, 1]: LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 24824 W: 3732 L: 3617 D: 17475 Elo +1.61 http://tests.stockfishchess.org/tests/view/5af04d3f0ebc5902a88b2e55 ELO 1.27 [-1.21,3.70] (95%) Closes https://github.com/official-stockfish/Stockfish/pull/1584 How to continue from there? There were some promising tests a couple of months ago about adding a lever condition for king danger in evaluate.cpp, maybe it would be time to re-try this after all the recent changes in pawns.cpp Bench: 4773882 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Joost VandeVondele
Date: Tue May 8 10:43:56 2018 +0200 Timestamp: 1525769036 Remove skipEarlyPruning argument to search() Remove nine boolean arguments and the corresponding skipEarlyPruning variable. Instead, skip early pruning only when there is an excluded move, and try null move pruning only if the previous move was not itself a null move. passed STC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 33623 W: 6853 L: 6755 D: 20015 Elo +1.01 http://tests.stockfishchess.org/tests/view/5aef462a0ebc5902a409a10e passed LTC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 39474 W: 5882 L: 5789 D: 27803 Elo +0.82 http://tests.stockfishchess.org/tests/view/5aefd4b80ebc5902a409a164 Closes https://github.com/official-stockfish/Stockfish/pull/1585 Bench: 4953556 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Joost VandeVondele
Date: Tue May 8 10:32:23 2018 +0200 Timestamp: 1525768343 Improve signature script Catch case of missing bench, indicative of a crash or assert. No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: protonspring
Date: Sun May 6 09:44:14 2018 +0200 Timestamp: 1525592654 Simplify the backward pawns code The two lines of code in the patch seem to be just as good as master. 1. We now only look at the current square to see if it is currently backward, whereas master looks there AND further ahead in the current file (master would declare a pawn "backward" even though it could still safely advance a little). This simplification allows us to avoid the use of the difficult logic with `backmost_sq(Us, neighbours | stoppers)`. 2. The condition `relative_rank(Us,s) < RANK_5` is simplified away. Passed STC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 68132 W: 14025 L: 13992 D: 40115 Elo +0.17 http://tests.stockfishchess.org/tests/view/5aedc97a0ebc5902a4099fd6 Passed LTC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 23789 W: 3643 L: 3527 D: 16619 Elo +1.69 http://tests.stockfishchess.org/tests/view/5aee4f970ebc5902a409a03a Ideas for further work: • The new code flags some pawns on the 5th rank as backward, which was not the case in the old master. So maybe we should test a version with that included? • Further tweaks of the backward condition with [0..5] bounds? Closes https://github.com/official-stockfish/Stockfish/pull/1583 Bench: 5122789 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Stéphane Nicolet
Date: Thu May 3 22:00:07 2018 +0200 Timestamp: 1525377607 Tweak the connected[] array value for pawns on rank 5 A recent tuning session by Jerry Donald Watson suggested that the value for the pawns on the fifth rank in the connected[] array were a little bit too high in master. We lower here this value from 75 to 65. STC: LLR: 2.95 (-2.94,2.94) [0.00,4.00] Total: 27399 W: 5646 L: 5384 D: 16369 Elo +3.32 http://tests.stockfishchess.org/tests/view/5aea17c50ebc5902a1bed396 LTC: LLR: 3.66 (-2.94,2.94) [0.00,4.00] Total: 95590 W: 14529 L: 14062 D: 66999 Elo +1.70 http://tests.stockfishchess.org/tests/view/5aea34a40ebc5902a104ebe5 Closes https://github.com/official-stockfish/Stockfish/pull/1580 Bench: 5186783 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: Stéphane Nicolet
Date: Wed May 2 13:38:00 2018 +0200 Timestamp: 1525261080 Correct a bug introduced by Stéphane in the previous patch. When we are using the "Bitboard + Square" overloaded operators, the compiler uses the interpediate SquareBB[s] to transform the square into a Bitboard, and then calculate the result. For instance, the following code: ``` b = pos.pieces(Us, PAWN) & s ``` generates in fact the code: ``` b = pos.pieces(Us, PAWN) & SquareBB[s]` ``` The bug introduced by Stéphane in the previous patch was the use of `b = pos.pieces(Us, PAWN) & (s + Up)` which can result in out-of-bounds errors for the SquareBB[] array if s in the last rank of the board. We coorect the bug, and also add some asserts in bitboard.h to make the code more robust for this particular bug in the future. Bug report by Joost VandeVondele. Thanks! Bench: 5512000 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 Windows 32 Linux x64 for Haswell CPUs Linux x64 for modern computers Linux x64 | Author: protonspring
Date: Tue May 1 23:55:30 2018 +0200 Timestamp: 1525211730 Use special rule for BlockedByKing Simplification: remove BlockedByKing from storm array and use a special rule. The BlockedByKing section in the storm array is substantially similar to the Unopposed section except for two extreme values V(-290), V(-274). Turns out removing BlockedByKing and using a special rule for these two values shows no Elo loss. All the other values in the BlockedByKing section are apparently irrelevant. BlockedByKing now falls under unopposed which (to me) is a bit more logical since there is no defending pawn on this file. Also, retuning the Unopposed section may be another improvement. GOOD) This is a simplification because the entire BlockedByKing section of the storm array goes away reducing a few lines of code (and less values to tune). This also brings clarity because the special rule is self documenting. BAD) It takes execution time to apply the special rule. This should be negli- gible because it is based on a template parameter and is boiled down to two bitwise AND's. STC: LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 33470 W: 6820 L: 6721 D: 19929 Elo +1.03 http://tests.stockfishchess.org/tests/view/5ae7b6e60ebc5926dba90e13 LTC: LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 47627 W: 7045 L: 6963 D: 33619 Elo +0.60 http://tests.stockfishchess.org/tests/view/5ae859ff0ebc5926dba90e85 Closes https://github.com/official-stockfish/Stockfish/pull/1574 Bench: 5512000 ----------- How to continue after this patch? This patch may open the possibility to move the special rule to evaluate.cpp in the evaluate::king() function, where we could refine the rule using king danger information. For instance, with a king in H2 blocking an opponent pawn in H3, it may be critical to know that the opponent has no safe check in G2 before giving the bonus :-) see source |