Latest abrok Development Versions June 28th (SF The gift that keeps on giving )

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: Sun Jun 28 22:42:43 2020 +0200 Timestamp: 1593376963 Scale down eval for queen imbalance We lower the endgame value of the evaluation when we detect that there is only one queen left on the board (more precisely, we use a scale factor of 37/64, or about 0.58, for the endgame part of the evaluation). Hopefully this helps a little bit for the assessment of positions with queen imbalance, which are one of the well-known Stockfish weaknesses. STC: LLR: 2.94 (-2.94,2.94) {-0.50,1.50} Total: 21600 W: 4176 L: 3955 D: 13469 Elo +3.55 Ptnml(0-2): 351, 2457, 5003, 2598, 391 https://tests.stockfishchess.org/tests/view/5ef871b6020eec13834a94e8 LTC: LLR: 2.97 (-2.94,2.94) {0.25,1.75} Total: 248328 W: 30596 L: 29720 D: 188012 Elo +1.23 Ptnml(0-2): 1544, 22345, 75665, 22911, 1699 https://tests.stockfishchess.org/tests/view/5ef87aec020eec13834a94fe Closes https://github.com/official-stockfish/Stockfish/pull/2781 Bench: 4441323
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: Sun Jun 28 22:05:09 2020 +0200 Timestamp: 1593374709 Scale down eval for drawish rook endgames. STC: LLR: 2.96 (-2.94,2.94) {-0.50,1.50} Total: 82136 W: 15694 L: 15407 D: 51035 Elo +1.21 Ptnml(0-2): 1076, 8960, 20767, 9131, 1134 https://tests.stockfishchess.org/tests/view/5ef86cf8020eec13834a94dd LTC: LLR: 2.93 (-2.94,2.94) {0.25,1.75} Total: 70200 W: 8787 L: 8440 D: 52973 Elo +1.72 Ptnml(0-2): 325, 5983, 22170, 6264, 358 https://tests.stockfishchess.org/tests/view/5ef88225020eec13834a950a closes https://github.com/official-stockfish/Stockfish/pull/2780 Bench: 4478869
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: Sun Jun 28 22:03:10 2020 +0200 Timestamp: 1593374590 Increase value of pawns on fifth rank This patch increases the endgame value of pawns on the fifth rank. The increase is very small (+1 evaluation point, about 0.005 pawn) for the pawns on external columns (a-b-c-f-g-h) and a bit bigger (+7 evaluation points, about 0.033 pawn) for the pawns on d5/e5. STC: LLR: 2.93 (-2.94,2.94) {-0.50,1.50} Total: 79864 W: 15331 L: 15027 D: 49506 Elo +1.32 Ptnml(0-2): 1336, 9284, 18433, 9498, 1381 https://tests.stockfishchess.org/tests/view/5ef73e2ef993893290cc0c47 LTC: LLR: 2.94 (-2.94,2.94) {0.25,1.75} Total: 47240 W: 5927 L: 5630 D: 35683 Elo +2.18 Ptnml(0-2): 320, 4133, 14440, 4384, 343 https://tests.stockfishchess.org/tests/view/5ef7c0c4f993893290cc14b7 closes https://github.com/official-stockfish/Stockfish/pull/2776 Bench: 4794633
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: mstembera Date: Sun Jun 28 22:00:19 2020 +0200 Timestamp: 1593374419 Remove old zobrist trick for castling rights Removes an 8 year old micro optimization aimed at 32-bit architectures because back then doing an xor of a Key could not be done in one instruction. See original commit here 821e1c7 STC https://tests.stockfishchess.org/tests/view/5ef5833dde213bf647527d0c LLR: 2.94 (-2.94,2.94) {-1.50,0.50} Total: 162648 W: 31053 L: 31097 D: 100498 Elo -0.09 Ptnml(0-2): 2841, 18966, 37715, 19000, 2802 LTC https://tests.stockfishchess.org/tests/view/5ef7b1bbf993893290cc1489 LLR: 2.93 (-2.94,2.94) {-1.50,0.50} Total: 62360 W: 7617 L: 7586 D: 47157 Elo +0.17 Ptnml(0-2): 423, 5662, 18994, 5663, 438 closes https://github.com/official-stockfish/Stockfish/pull/2775 bench: 4591425
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: mstembera Date: Sun Jun 28 21:57:37 2020 +0200 Timestamp: 1593374257 Fix fragile code to use proper random 64 bit keys. This fixes an old issue where we want to make a position unique but only change a small number of bits in the key instead of all 64 of them randomly. This is fragile and can lead to non uniqueness issues in the TT. Key make_key(uint64_t seed) takes any integer and produces a unique random 64 bit key. It is computationally efficient and is based on a congruential pseudo random number generator using well tested constants by Donald Knuth (see https://en.wikipedia.org/wiki/Linear_congruential_generator) STC https://tests.stockfishchess.org/tests/view/5ef6c78f761b685b4c724bb6 LLR: 2.95 (-2.94,2.94) {-1.50,0.50} Total: 154320 W: 29343 L: 29376 D: 95601 Elo -0.07 Ptnml(0-2): 2543, 18170, 35891, 17889, 2667 LTC https://tests.stockfishchess.org/tests/view/5ef7d1a9020eec13834a940e LLR: 2.95 (-2.94,2.94) {-1.50,0.50} Total: 53488 W: 6629 L: 6584 D: 40275 Elo +0.29 Ptnml(0-2): 372, 4878, 16183, 4955, 356 closes https://github.com/official-stockfish/Stockfish/pull/2773 bench: 4626776

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