Shawn Xu and Joost VandeVondele
adfddd2c98
Add scaling note to STC/LTC tunes
...
It has been repeatedly shown that such tunes are suspectible to become
anti-scaling. Below are some recent examples:
https://github.com/official-stockfish/Stockfish/commit/2e91a8635468e40c89a2303ce50384864d088611
https://github.com/official-stockfish/Stockfish/commit/d11f49b790429c236a1a4169f0d8052635fc03dc
Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 32448 W: 8651 L: 8342 D: 15455
Ptnml(0-2): 81, 3695, 8408, 3914, 126
https://tests.stockfishchess.org/tests/view/6899489b0049e8ccef9d64ad
Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 73854 W: 19042 L: 18649 D: 36163
Ptnml(0-2): 37, 7908, 20659, 8271, 52
https://tests.stockfishchess.org/tests/view/689abbe7fd8719b088c8d514
Revert VVLTC with STC bound:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 53802 W: 14030 L: 13740 D: 26032
Ptnml(0-2): 5, 4924, 16754, 5212, 6
https://tests.stockfishchess.org/tests/view/68a9a9f575da51a345a5a675
Revert VVLTC with LTC bound:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 53658 W: 14022 L: 13699 D: 25937
Ptnml(0-2): 3, 4894, 16712, 5217, 3
https://tests.stockfishchess.org/tests/view/68a8d2b2b6fb3300203bca77
https://tests.stockfishchess.org/tests/view/688cf38bf17748b4d23c8057
https://tests.stockfishchess.org/tests/view/6890bc7792fcad741b804a19
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 74928 W: 19466 L: 19071 D: 36391
Ptnml(0-2): 37, 8048, 20901, 8439, 39
Failed Non-regression VLTC:
LLR: -2.94 (-2.94,2.94) <-1.75,0.25>
Total: 57704 W: 14643 L: 14928 D: 28133
Ptnml(0-2): 5, 5925, 17280, 5634, 8
https://tests.stockfishchess.org/tests/view/6890bc7792fcad741b804a19
(Note that an STC-tuned version passed non-regression, but was shortly
simplified)
https://github.com/official-stockfish/Stockfish/pull/6040
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 27776 W: 7352 L: 7054 D: 13370
Ptnml(0-2): 68, 3126, 7221, 3386, 87
https://tests.stockfishchess.org/tests/view/680ec0f83629b02d74b1605b
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 161304 W: 41432 L: 40864 D: 79008
Ptnml(0-2): 61, 17305, 45357, 17863, 66
https://tests.stockfishchess.org/tests/view/680ec7f93629b02d74b16084
Failed Non-regression VVLTC:
LLR: -2.94 (-2.94,2.94) <-1.75,0.25>
Total: 313466 W: 80573 L: 81089 D: 151804
Ptnml(0-2): 38, 29689, 97782, 29199, 25
https://tests.stockfishchess.org/tests/view/6810d0533629b02d74b16756
https://github.com/official-stockfish/Stockfish/pull/5907
https://github.com/official-stockfish/Stockfish/pull/5887
Passed LTC with STC bounds:
https://tests.stockfishchess.org/tests/view/67b115dd6c6b9e172ad1592f
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 75756 W: 19393 L: 19044 D: 37319
Ptnml(0-2): 60, 8251, 20913, 8588, 66
Passed LTC with LTC bounds:
https://tests.stockfishchess.org/tests/view/67af5f5d6c6b9e172ad15765
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 108126 W: 27880 L: 27412 D: 52834
Ptnml(0-2): 85, 11786, 29866, 12228, 98
Revert VVLTC w/ STC bounds:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 56342 W: 14536 L: 14246 D: 27560
Ptnml(0-2): 7, 5061, 17741, 5359, 3
https://tests.stockfishchess.org/tests/view/67be4f8ad8d5c2c657c52d10
Revert VVLTC w/ LTC bounds:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 66562 W: 17364 L: 17016 D: 32182
Ptnml(0-2): 3, 6145, 20637, 6493, 3
https://tests.stockfishchess.org/tests/view/67bcd25ff6b602bd7222ea40
closes https://github.com/official-stockfish/Stockfish/pull/6284
no functional change
2025-09-02 20:42:03 +02:00
Shawn Xu and Joost VandeVondele
f2da0ccf3f
Simplify SMP Reduction
...
Passed Non-regression SMP STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 232784 W: 59845 L: 59841 D: 113098
Ptnml(0-2): 289, 26459, 62934, 26379, 331
https://tests.stockfishchess.org/tests/view/68ab96bf75da51a345a5acd6
Passed Non-regression SMP LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 374270 W: 95978 L: 96113 D: 182179
Ptnml(0-2): 118, 38575, 109888, 38432, 122
https://tests.stockfishchess.org/tests/view/68abcf1c75da51a345a5adb6
closes https://github.com/official-stockfish/Stockfish/pull/6285
Bench: 2667107
2025-09-02 20:41:08 +02:00
Shawn Xu and Joost VandeVondele
75ac6c7a06
simplify stalemate further
...
Non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 155200 W: 40650 L: 40562 D: 73988
Ptnml(0-2): 533, 17588, 41258, 17700, 521
https://tests.stockfishchess.org/tests/view/68abe11375da51a345a5adec
Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 82824 W: 21442 L: 21287 D: 40095
Ptnml(0-2): 51, 8738, 23675, 8901, 47
https://tests.stockfishchess.org/tests/view/68b205606217b8721dca9c8e
10k Stalemate:
Elo: 1.46 ± 1.2 (95%) LOS: 99.0%
Total: 10000 W: 4640 L: 4598 D: 762
Ptnml(0-2): 0, 140, 4678, 182, 0
https://tests.stockfishchess.org/tests/view/68b2059b6217b8721dca9c90
closes https://github.com/official-stockfish/Stockfish/pull/6283
Bench: 2431727
2025-09-02 20:39:02 +02:00
Daniel Monroe and Joost VandeVondele
da63060ea3
Simplify sign term in quiet histories
...
Simplify sign term in quiet histories
Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 497824 W: 129130 L: 129418 D: 239276
Ptnml(0-2): 1546, 59040, 128008, 58792, 1526
https://tests.stockfishchess.org/tests/view/68a2a9c1b6fb3300203bc3ed
Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 70830 W: 18185 L: 18016 D: 34629
Ptnml(0-2): 36, 7658, 19861, 7821, 39
https://tests.stockfishchess.org/tests/view/68af36c96217b8721dca98d9
closes https://github.com/official-stockfish/Stockfish/pull/6282
Bench: 2393762
2025-09-02 20:37:04 +02:00
Joost VandeVondele and xu-shawn
3833583862
limit dynamic reduction.
...
fixes https://github.com/official-stockfish/Stockfish/issues/6280
prevents probcut from extending depth as analyzed here:
https://github.com/official-stockfish/Stockfish/pull/6254#issuecomment-3239144280
passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 86688 W: 22591 L: 22426 D: 41671
Ptnml(0-2): 305, 10125, 22311, 10306, 297
https://tests.stockfishchess.org/tests/view/68b418ab467ff96994ae4cd5
passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 82914 W: 21287 L: 21130 D: 40497
Ptnml(0-2): 39, 8959, 23305, 9114, 40
https://tests.stockfishchess.org/tests/view/68b47ffa78ed7a752a9e8f36
closes https://github.com/official-stockfish/Stockfish/pull/6286
Bench: 2787731
Co-Authored-By: xu-shawn <50402888+xu-shawn@users.noreply.github.com >
2025-09-02 20:34:47 +02:00
Shawn Xu and Joost VandeVondele
3f18352396
Further Simplify Stalemate Detection
...
Passed Non-regression STC:
LLR: 2.98 (-2.94,2.94) <-1.75,0.25>
Total: 191520 W: 49633 L: 49582 D: 92305
Ptnml(0-2): 557, 20676, 53260, 20693, 574
https://tests.stockfishchess.org/tests/view/68ab570075da51a345a5abe1
Passed Non-regression LTC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 212934 W: 54643 L: 54618 D: 103673
Ptnml(0-2): 117, 22417, 61364, 22462, 107
https://tests.stockfishchess.org/tests/view/68ab84e975da51a345a5ac6b
10k Stalemate:
Elo: 0.35 ± 1.2 (95%) LOS: 71.6%
Total: 10000 W: 4602 L: 4592 D: 806
Ptnml(0-2): 0, 148, 4694, 158, 0
nElo: 1.99 ± 6.8 (95%) PairsRatio: 1.07
https://tests.stockfishchess.org/tests/view/68abeb8175da51a345a5af82
closes https://github.com/official-stockfish/Stockfish/pull/6268
Bench: 2420973
2025-08-30 15:12:06 +02:00
7d213afd37
Non-functional simplifications
...
closes https://github.com/official-stockfish/Stockfish/pull/6267
No functional change
Co-authored-by: Daniel Monroe <github.com@danielmonroe.net >
2025-08-30 15:09:47 +02:00
Shawn Xu and Joost VandeVondele
a289ee389a
Simplify Capture Futility Pruning
...
Passed Non-regression STC:
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 187904 W: 48639 L: 48583 D: 90682
Ptnml(0-2): 560, 22150, 48502, 22154, 586
https://tests.stockfishchess.org/tests/view/68aad56075da51a345a5a9e3
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 94302 W: 24246 L: 24101 D: 45955
Ptnml(0-2): 44, 10274, 26371, 10417, 45
https://tests.stockfishchess.org/tests/view/68ab541975da51a345a5aacf
closes https://github.com/official-stockfish/Stockfish/pull/6266
Bench: 2376717
2025-08-30 15:09:00 +02:00
Nonlinear2 and Joost VandeVondele
75f07da912
Avoid high rule50 count zeroing cutoffs
...
If the depth is low enough, don't TT cut if the rule50 count is high and the TT move is zeroing.
Passed STC:
https://tests.stockfishchess.org/tests/view/68a8fdd8b6fb3300203bcb92
LLR: 3.05 (-2.94,2.94) <0.00,2.00>
Total: 110304 W: 28805 L: 28402 D: 53097
Ptnml(0-2): 275, 11174, 31875, 11529, 299
Passed LTC:
https://tests.stockfishchess.org/tests/view/68aa200f75da51a345a5a809
LLR: 3.00 (-2.94,2.94) <0.50,2.50>
Total: 187956 W: 48489 L: 47928 D: 91539
Ptnml(0-2): 59, 16118, 61075, 16655, 71
closes https://github.com/official-stockfish/Stockfish/pull/6271
bench: 2641840
2025-08-30 15:05:11 +02:00
Shawn Xu and Joost VandeVondele
678d503d8f
Simplify LMR Extensions
...
Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 236896 W: 61683 L: 61683 D: 113530
Ptnml(0-2): 730, 28057, 60901, 28003, 757
https://tests.stockfishchess.org/tests/view/68a9c20475da51a345a5a6a0
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 73644 W: 18936 L: 18770 D: 35938
Ptnml(0-2): 33, 7951, 20685, 8123, 30
https://tests.stockfishchess.org/tests/view/68aa95c575da51a345a5a88a
closes https://github.com/official-stockfish/Stockfish/pull/6265
Bench: 2693376
2025-08-24 20:10:43 +02:00
Stefan Geschwentner and Joost VandeVondele
39c077f15a
Less reduction for later threads.
...
Give "(thread id mod 8) * 64" less reductions (up to nearly a half ply).
Passed SMP STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 413176 W: 106496 L: 105666 D: 201014
Ptnml(0-2): 504, 46732, 111266, 47602, 484
https://tests.stockfishchess.org/tests/view/68a24aeeb6fb3300203bbdc4
Passed SMP LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 60420 W: 15622 L: 15268 D: 29530
Ptnml(0-2): 11, 6106, 17632, 6440, 21
https://tests.stockfishchess.org/tests/view/68a2c2ffb6fb3300203bc516
closes https://github.com/official-stockfish/Stockfish/pull/6249
No functional change
2025-08-24 20:07:50 +02:00
FauziAkram and Joost VandeVondele
c99eb8ef32
Remove cap from a bonusScale formula
...
Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 127264 W: 33159 L: 33042 D: 61063
Ptnml(0-2): 336, 14509, 33866, 14544, 377
https://tests.stockfishchess.org/tests/view/68a63fccb6fb3300203bc818
Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 469512 W: 120094 L: 120331 D: 229087
Ptnml(0-2): 238, 51317, 131885, 51076, 240
https://tests.stockfishchess.org/tests/view/68a8d867b6fb3300203bcab5
closes https://github.com/official-stockfish/Stockfish/pull/6260
Bench: 2433974
2025-08-24 20:01:01 +02:00
Shawn Xu and Joost VandeVondele
e2fdf6f005
Simplify separate malus formulas
...
Passed Non-regression STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 16352 W: 4336 L: 4090 D: 7926
Ptnml(0-2): 54, 1832, 4157, 2080, 53
https://tests.stockfishchess.org/tests/view/68a808f0b6fb3300203bca08
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 94014 W: 24129 L: 23986 D: 45899
Ptnml(0-2): 47, 9917, 26934, 10064, 45
https://tests.stockfishchess.org/tests/view/68a8f45cb6fb3300203bcb5e
closes https://github.com/official-stockfish/Stockfish/pull/6256
Bench: 2483704
2025-08-24 19:55:35 +02:00
Shawn Xu and Joost VandeVondele
901ad7e7ee
Simplify quiet move streak
...
Passed Non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 46272 W: 12076 L: 11866 D: 22330
Ptnml(0-2): 140, 5407, 11860, 5561, 168
https://tests.stockfishchess.org/tests/view/68a9c26575da51a345a5a6a2
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 140442 W: 35984 L: 35886 D: 68572
Ptnml(0-2): 72, 15333, 39305, 15447, 64
https://tests.stockfishchess.org/tests/view/68aa245e75da51a345a5a80d
closes https://github.com/official-stockfish/Stockfish/pull/6258
Bench: 2931171
2025-08-24 19:52:42 +02:00
Shawn Xu and Joost VandeVondele
85f87649bf
Simplify stalemate detection
...
Passed Non-regression STC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 107392 W: 27959 L: 27818 D: 51615
Ptnml(0-2): 317, 12094, 28735, 12231, 319
https://tests.stockfishchess.org/tests/view/68a65d8ab6fb3300203bc825
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 94014 W: 24129 L: 23986 D: 45899
Ptnml(0-2): 47, 9917, 26934, 10064, 45
https://tests.stockfishchess.org/tests/view/68a8f45cb6fb3300203bcb5e
Passed Stalemate 10k:
Elo: 2.22 ± 1.3 (95%) LOS: 100.0%
Total: 10000 W: 4626 L: 4562 D: 812
Ptnml(0-2): 1, 137, 4659, 203, 0
nElo: 12.00 ± 6.8 (95%) PairsRatio: 1.47
https://tests.stockfishchess.org/tests/view/68a65d8ab6fb3300203bc825
Supersedes #6114
Closes #6232
closes https://github.com/official-stockfish/Stockfish/pull/6255
Bench: 2473929
2025-08-24 19:50:51 +02:00
Daniel Monroe and Joost VandeVondele
7fa7a36dc6
Remove upper bound in see margin
...
Passed simplification STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 99840 W: 25965 L: 25815 D: 48060
Ptnml(0-2): 326, 11708, 25688, 11886, 312
https://tests.stockfishchess.org/tests/view/68a24504b6fb3300203bbdae
Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 248388 W: 63544 L: 63556 D: 121288
Ptnml(0-2): 125, 27132, 69709, 27086, 142
https://tests.stockfishchess.org/tests/view/68a24f3bb6fb3300203bbdee
closes https://github.com/official-stockfish/Stockfish/pull/6250
Bench: 2432765
2025-08-24 19:47:20 +02:00
Daniel Samek and Joost VandeVondele
2659351ce7
Remove depth reduction in the full-depth search
...
Passed simplification STC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 217184 W: 56218 L: 56195 D: 104771
Ptnml(0-2): 627, 25673, 55985, 25664, 643
https://tests.stockfishchess.org/tests/view/68a21e0eb6fb3300203bbcf3
Passed simplification LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 30474 W: 7923 L: 7713 D: 14838
Ptnml(0-2): 20, 3205, 8569, 3431, 12
https://tests.stockfishchess.org/tests/view/68a2adacb6fb3300203bc3f9
closes https://github.com/official-stockfish/Stockfish/pull/6246
bench 2626263
2025-08-24 19:45:23 +02:00
Daniel Monroe and Joost VandeVondele
57d76bd459
Simplify depth condition in prior reduction
...
Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 172864 W: 45085 L: 45015 D: 82764
Ptnml(0-2): 516, 20456, 44405, 20552, 503
https://tests.stockfishchess.org/tests/view/68a24791b6fb3300203bbdb6
Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 84738 W: 21733 L: 21578 D: 41427
Ptnml(0-2): 49, 9169, 23780, 9320, 51
https://tests.stockfishchess.org/tests/view/68a2665ab6fb3300203bc269
closes https://github.com/official-stockfish/Stockfish/pull/6244
Bench: 2131292
2025-08-24 19:43:48 +02:00
FauziAkram and Joost VandeVondele
176ef577e2
Set back static constexpr
...
closes https://github.com/official-stockfish/Stockfish/pull/6243
No functional change
2025-08-24 19:39:49 +02:00
Stefan Geschwentner and Joost VandeVondele
d11f49b790
Remove log depth reduction terms.
...
Motivated by the elo loss of last VVLTC regression test i remove the new log
depth reductions (tuned at STC) to regain strength at VVLTC. The constant terms
are adjusted based on the old values and the changes from the last added VVLTC
tuning.
Passed VVLTC with STC bound:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 53802 W: 14030 L: 13740 D: 26032
Ptnml(0-2): 5, 4924, 16754, 5212, 6
https://tests.stockfishchess.org/tests/view/68a9a9f575da51a345a5a675
Passed VVLTC with LTC bound:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 53658 W: 14022 L: 13699 D: 25937
Ptnml(0-2): 3, 4894, 16712, 5217, 3
https://tests.stockfishchess.org/tests/view/68a8d2b2b6fb3300203bca77
closes https://github.com/official-stockfish/Stockfish/pull/6257
Bench: 2566780
2025-08-24 19:30:31 +02:00
FauziAkram and Joost VandeVondele
7fe46b5a70
VVLTC tweak
...
Passed VVLTC with STC bounds:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 60796 W: 15908 L: 15609 D: 29279
Ptnml(0-2): 6, 5598, 18889, 5901, 4
https://tests.stockfishchess.org/tests/view/68a1fbfeb6fb3300203bbc5c
Passed VVLTC with LTC bounds:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 24914 W: 6528 L: 6256 D: 12130
Ptnml(0-2): 4, 2263, 7648, 2541, 1
https://tests.stockfishchess.org/tests/view/68a211aeb6fb3300203bbca7
closes https://github.com/official-stockfish/Stockfish/pull/6241
Bench: 2130122
2025-08-17 22:46:04 +02:00
Stefan Geschwentner and Joost VandeVondele
8ecfc3c89d
Bigger thread dependent initial window.
...
Increase the initial delta of the aspiration window by "thread id mod 8".
Passed SMP STC:
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 106176 W: 27470 L: 27069 D: 51637
Ptnml(0-2): 121, 12032, 28386, 12423, 126
https://tests.stockfishchess.org/tests/view/68a178fab6fb3300203bbaec
Passed SMP LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 133076 W: 34272 L: 33772 D: 65032
Ptnml(0-2): 38, 13709, 38537, 14223, 31
https://tests.stockfishchess.org/tests/view/68a1b5d2b6fb3300203bbb71
closes https://github.com/official-stockfish/Stockfish/pull/6239
No functional change
2025-08-17 22:39:49 +02:00
Daniel Monroe and Joost VandeVondele
169737a9eb
Simplify dual bonuses
...
Merge dual capture/quiet bonuses into one
Passed simplification STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 223200 W: 57868 L: 57854 D: 107478
Ptnml(0-2): 689, 26441, 57296, 26515, 659
https://tests.stockfishchess.org/tests/view/6898d28e0049e8ccef9d6384
Passed simplification LTC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 147270 W: 37750 L: 37659 D: 71861
Ptnml(0-2): 84, 15869, 41633, 15970, 79
https://tests.stockfishchess.org/tests/view/68990fe30049e8ccef9d643c
closes https://github.com/official-stockfish/Stockfish/pull/6226
Bench: 2996176
2025-08-16 12:12:07 +02:00
Daniel Monroe and Joost VandeVondele
c9c002450a
Simplify depth term in reductions
...
Passed simplification STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 317344 W: 82352 L: 82442 D: 152550
Ptnml(0-2): 999, 37395, 81907, 37439, 932
https://tests.stockfishchess.org/tests/live_elo/68976798f8a258623dda6c46
Passed simplification LTC
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 291708 W: 74733 L: 74787 D: 142188
Ptnml(0-2): 159, 31813, 81956, 31775, 151
https://tests.stockfishchess.org/tests/live_elo/689791a5f8a258623dda6d03
closes https://github.com/official-stockfish/Stockfish/pull/6225
Bench: 2436991
2025-08-16 12:06:00 +02:00
Kevin Lu and Joost VandeVondele
0db4a1bee9
Remove completedDepth condition for SE
...
Just removing the term
Passed STC:
LLR: 3.27 (-2.94,2.94) <-1.75,0.25>
Total: 179840 W: 47211 L: 47126 D: 85503
Ptnml(0-2): 567, 17929, 52879, 17942, 603
https://tests.stockfishchess.org/tests/view/688bdd88502b34dd5e7111ea
Passed LTC:
LLR: 3.26 (-2.94,2.94) <-1.75,0.25>
Total: 150708 W: 38738 L: 38637 D: 73333
Ptnml(0-2): 79, 12922, 49262, 13001, 90
https://tests.stockfishchess.org/tests/view/688ce857f17748b4d23c8026
Passed VLTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 288312 W: 74104 L: 74152 D: 140056
Ptnml(0-2): 44, 26732, 90657, 26674, 49
https://tests.stockfishchess.org/tests/view/688ec4f57d68fe4f7f130ee3
closes https://github.com/official-stockfish/Stockfish/pull/6221
functional at higher depths
Bench: 3002300
2025-08-16 12:01:19 +02:00
FauziAkram and Joost VandeVondele
d864148595
Simplify beta formula
...
Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 152384 W: 39907 L: 39814 D: 72663
Ptnml(0-2): 557, 17958, 39053, 18083, 541
https://tests.stockfishchess.org/tests/view/6890b66692fcad741b804a10
Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 98688 W: 25411 L: 25270 D: 48007
Ptnml(0-2): 45, 10692, 27743, 10805, 59
https://tests.stockfishchess.org/tests/view/6896019c618946ab878347b0
closes: https://github.com/official-stockfish/Stockfish/pull/6220
bench: 3002300
2025-08-16 11:57:44 +02:00
Stefan Geschwentner and Joost VandeVondele
2e91a86354
Add log depth as term to reduction factors.
...
Replace most reduction factors with a linear term of the form X + Y * msb(depth) (using msb(depth) as simple and fast approximation for log(depth))
and tune the weights with following SPSA test: https://tests.stockfishchess.org/tests/view/689903860049e8ccef9d6415 .
Here the tuned values of X[8] and Y[8] were ignored because a simple test with this parameters alone failed badly (https://tests.stockfishchess.org/tests/view/68992b350049e8ccef9d6482 ).
Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 32448 W: 8651 L: 8342 D: 15455
Ptnml(0-2): 81, 3695, 8408, 3914, 126
https://tests.stockfishchess.org/tests/view/6899489b0049e8ccef9d64ad
Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 73854 W: 19042 L: 18649 D: 36163
Ptnml(0-2): 37, 7908, 20659, 8271, 52
https://tests.stockfishchess.org/tests/view/689abbe7fd8719b088c8d514
closes https://github.com/official-stockfish/Stockfish/pull/6229
Bench: 3151102
2025-08-16 11:51:39 +02:00
Jost Triller and Joost VandeVondele
7a07ac0e76
Adjust probcut on staticEval
...
Reducing probcut depth more when staticEval is very good and less if staticEval is not so good compared to beta
STC: https://tests.stockfishchess.org/tests/view/68926bf6690844f940fa1350
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 174400 W: 45698 L: 45174 D: 83528
Ptnml(0-2): 622, 20356, 44672, 20976, 574
LTC: https://tests.stockfishchess.org/tests/view/689651b4f8a258623dda6531
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 56010 W: 14547 L: 14191 D: 27272
Ptnml(0-2): 31, 5929, 15738, 6267, 40
This patch was generated using qwen3-235b-a22b-thinking-2507:
Prompt: https://rentry.co/bm6vriai
Thinking: https://rentry.co/34km4zf8
Final respone: https://rentry.co/rauotrvr
closes https://github.com/official-stockfish/Stockfish/pull/6219
Bench: 3629755
2025-08-09 09:08:38 +02:00
Stockfisher69 and Joost VandeVondele
303fe9a164
Simplification: Futility pruning for captures
...
tested in final form as simplication
passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 113682 W: 29199 L: 29074 D: 55409
Ptnml(0-2): 68, 12359, 31859, 12490, 65
https://tests.stockfishchess.org/tests/view/688e85a17d68fe4f7f130e24
earlier test, equivalent:
passed STC:
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 120224 W: 31621 L: 31176 D: 57427
Ptnml(0-2): 415, 14167, 30567, 14484, 479
https://tests.stockfishchess.org/tests/view/68888bdd7b562f5f7b732643
closes https://github.com/official-stockfish/Stockfish/pull/6209
Bench: 2661621
2025-08-09 08:49:12 +02:00
KazApps and Joost VandeVondele
b177b7394a
Separate bonus/malus parameters for quiet and capture moves
...
Parameters were tuned on 60k STC games.
Passed STC
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 16928 W: 4570 L: 4277 D: 8081
Ptnml(0-2): 57, 1905, 4270, 2152, 80
https://tests.stockfishchess.org/tests/view/688b4486502b34dd5e711122
Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 43602 W: 11373 L: 11041 D: 21188
Ptnml(0-2): 23, 4657, 12116, 4975, 30
https://tests.stockfishchess.org/tests/view/688c0eb5502b34dd5e71124b
Passed non-regression VLTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 181016 W: 46335 L: 46281 D: 88400
Ptnml(0-2): 33, 18177, 54034, 18231, 33
https://tests.stockfishchess.org/tests/view/688e0a77f17748b4d23c822b
closes https://github.com/official-stockfish/Stockfish/pull/6200
bench: 3435529
2025-08-09 08:43:49 +02:00
Jost Triller and Joost VandeVondele
377a3a5269
Depth dependent reduction threshold when full-depth re-search
...
STC: https://tests.stockfishchess.org/tests/view/68894d577b562f5f7b73273b
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 155072 W: 40651 L: 40150 D: 74271
Ptnml(0-2): 609, 18271, 39292, 18738, 626
LTC: https://tests.stockfishchess.org/tests/view/688c2705502b34dd5e71127a
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 321012 W: 82891 L: 81995 D: 156126
Ptnml(0-2): 227, 34421, 90285, 35375, 198
This commit was generated using qwen3-235b-a22b-thinking-2507:
Prompt: https://rentry.co/iqtaoht7
Reasoning/thinking: https://rentry.co/wm6t9hye
closes https://github.com/official-stockfish/Stockfish/pull/6210
Bench: 2983938
2025-08-04 15:12:55 +02:00
Shawn Xu and Joost VandeVondele
14a2e50a3d
Simplify key after
...
Passed Non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 534016 W: 139438 L: 139771 D: 254807
Ptnml(0-2): 2098, 63469, 136136, 63278, 2027
https://tests.stockfishchess.org/tests/view/688ac64d502b34dd5e7110a4
Passed Non-regression LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 43980 W: 11346 L: 11149 D: 21485
Ptnml(0-2): 31, 4689, 12353, 4886, 31
https://tests.stockfishchess.org/tests/view/688ea8a47d68fe4f7f130eb3
closes https://github.com/official-stockfish/Stockfish/pull/6207
Bench: 2884232
2025-08-04 15:07:37 +02:00
Michael Chaly and Joost VandeVondele
5d1505d8c7
Reintroduce reduction term in LMR for cutnodes
...
This term increases reduction for cutnodes without tt move, term was simplified away recently.
Passed STC:
https://tests.stockfishchess.org/tests/view/688882007b562f5f7b73262f
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 187616 W: 49367 L: 48824 D: 89425
Ptnml(0-2): 710, 21898, 48034, 22471, 695
Passed LTC:
https://tests.stockfishchess.org/tests/view/688c71f4502b34dd5e71139a
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 140280 W: 36280 L: 35750 D: 68250
Ptnml(0-2): 79, 15175, 39121, 15667, 98
closes https://github.com/official-stockfish/Stockfish/pull/6206
Bench: 2996732
2025-08-04 14:58:59 +02:00
FauziAkram and Joost VandeVondele
8e733d68fd
Refactor: Simplify pawn structure indexing
...
Refactoring the mechanism for calculating pawn structure hash indices and make it consistent with the rest.
closes https://github.com/official-stockfish/Stockfish/pull/6205
No functional change
2025-08-04 14:56:03 +02:00
FauziAkram and Joost VandeVondele
a37b38bdf0
Add "d < newDepth" condition for doDeeperSearch
...
Add "d < newDepth" condition for doDeeperSearch
Passed STC:
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 66144 W: 17512 L: 17148 D: 31484
Ptnml(0-2): 220, 7726, 16833, 8056, 237
https://tests.stockfishchess.org/tests/view/6887cce67b562f5f7b731a79
Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 411240 W: 106103 L: 105023 D: 200114
Ptnml(0-2): 256, 44249, 115566, 45257, 292
https://tests.stockfishchess.org/tests/view/6887ec527b562f5f7b731c37
closes https://github.com/official-stockfish/Stockfish/pull/6204
Bench: 2917036
2025-08-02 16:25:31 +02:00
Daniel Monroe and Joost VandeVondele
cd52859bd5
Simplify improving term
...
Set improving whenever ss->staticEval >= beta
Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 38016 W: 10122 L: 9900 D: 17994
Ptnml(0-2): 143, 4388, 9747, 4564, 166
https://tests.stockfishchess.org/tests/view/688803917b562f5f7b7322eb
Passed simplification LTC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 21648 W: 5594 L: 5375 D: 10679
Ptnml(0-2): 12, 2241, 6096, 2466, 9
https://tests.stockfishchess.org/tests/view/688820397b562f5f7b73235d
closes https://github.com/official-stockfish/Stockfish/pull/6198
Bench: 3576884
2025-08-02 16:18:46 +02:00
CSTENTOR and Joost VandeVondele
57b32f3e60
Make Resetting the Aspiration Window after FailLow more aggressive
...
Sets beta=(3alpha+beta)/4 when failLow. Before it was beta=(alpha+beta)/2, even
though in theory we should be getting an upper bound from a failLow, we can’t
trust the score that caused the failLow. Therefore beta=alpha doesn’t work. I
made the buffer between the new beta to the bestValue that caused the failLow
smaller.
passed STC:
https://tests.stockfishchess.org/tests/view/688674947b562f5f7b7315b5
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 119616 W: 31253 L: 30818 D: 57545
Ptnml(0-2): 313, 14028, 30724, 14397, 346
passed LTC:
https://tests.stockfishchess.org/tests/view/6887e0ad7b562f5f7b731afc
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 96978 W: 24905 L: 24466 D: 47607
Ptnml(0-2): 59, 10376, 27183, 10809, 62
closes https://github.com/official-stockfish/Stockfish/pull/6197
bench: 3085519
2025-08-02 16:12:12 +02:00
aronpetkovski and Joost VandeVondele
cef551092c
Only do IIR in minimally reduced nodes
...
Passed STC
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 164256 W: 42799 L: 42299 D: 79158
Ptnml(0-2): 451, 19305, 42087, 19863, 422
https://tests.stockfishchess.org/tests/view/68868e9b7b562f5f7b731615
Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 279396 W: 71871 L: 71062 D: 136463
Ptnml(0-2): 126, 30117, 78404, 30924, 127
https://tests.stockfishchess.org/tests/view/6886a4977b562f5f7b731663
closes https://github.com/official-stockfish/Stockfish/pull/6196
Bench: 3490609
2025-08-02 16:02:41 +02:00
FauziAkram and Joost VandeVondele
fdd9c34b75
Re-adding ttHit condition, but this time in the inner block
...
Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 150240 W: 39305 L: 38819 D: 72116
Ptnml(0-2): 536, 17541, 38494, 17999, 550
https://tests.stockfishchess.org/tests/view/6887ce577b562f5f7b731a85
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 159120 W: 41025 L: 40461 D: 77634
Ptnml(0-2): 96, 16974, 44866, 17518, 106
https://tests.stockfishchess.org/tests/view/6887f0ba7b562f5f7b731c5d
closes https://github.com/official-stockfish/Stockfish/pull/6193
bench: 3498926
2025-08-02 15:50:17 +02:00
aronpetkovski and Joost VandeVondele
64e8e1b247
Simplify LMR extension limit formula
...
This patch simplifies the maximum depth formula that reductions in LMR can allow.
Passed STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 35616 W: 9358 L: 9139 D: 17119
Ptnml(0-2): 101, 4051, 9278, 4284, 94
https://tests.stockfishchess.org/tests/view/688608cf966ed85face24882
Passed LTC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 22284 W: 5833 L: 5613 D: 10838
Ptnml(0-2): 8, 2367, 6173, 2585, 9
https://tests.stockfishchess.org/tests/view/68860d7f966ed85face248d5
closes https://github.com/official-stockfish/Stockfish/pull/6191
Bench: 2902492
2025-07-28 20:18:55 +02:00
Daniel Monroe and Joost VandeVondele
525a5749bc
Simplify extra continuation history updates
...
Passed simplification STC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 254464 W: 65774 L: 65793 D: 122897
Ptnml(0-2): 699, 30087, 65638, 30150, 658
https://tests.stockfishchess.org/tests/view/68863283966ed85face24a59
Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 144750 W: 37111 L: 37018 D: 70621
Ptnml(0-2): 79, 15676, 40764, 15785, 71
https://tests.stockfishchess.org/tests/view/6886655f7b562f5f7b731359
closes https://github.com/official-stockfish/Stockfish/pull/6189
Bench: 3071078
2025-07-28 20:13:15 +02:00
Styx and Joost VandeVondele
ab83d320b8
Simplify NMP condition
...
As this is tried only for cutNode, and all children of cutNodes will be nonCutNodes, the guard condition is redundant.
Simplification just removes the unnecessary condition (always true).
closes https://github.com/official-stockfish/Stockfish/pull/6187
No functional change
2025-07-28 20:11:40 +02:00
FauziAkram and Joost VandeVondele
a9b7638e96
Simplify newDepth modification formulas
...
Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 21856 W: 5709 L: 5471 D: 10676
Ptnml(0-2): 77, 2466, 5589, 2734, 62
https://tests.stockfishchess.org/tests/view/68862ea4966ed85face24a27
Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 108828 W: 27893 L: 27763 D: 53172
Ptnml(0-2): 59, 11860, 30435, 12012, 48
https://tests.stockfishchess.org/tests/view/68863046966ed85face24a3b
closes https://github.com/official-stockfish/Stockfish/pull/6181
Bench: 3069051
2025-07-28 20:03:05 +02:00
Nonlinear2 and Joost VandeVondele
2e2d2778fc
increase futility value when capturing last moved piece
...
Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 204320 W: 53059 L: 52500 D: 98761
Ptnml(0-2): 551, 23874, 52778, 24379, 578
https://tests.stockfishchess.org/tests/view/688618ae966ed85face24976
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 138582 W: 35748 L: 35225 D: 67609
Ptnml(0-2): 62, 14874, 38900, 15389, 66
https://tests.stockfishchess.org/tests/view/68862717966ed85face249f2
closes https://github.com/official-stockfish/Stockfish/pull/6190
Bench: 2894413
2025-07-28 19:52:40 +02:00
FauziAkram and Joost VandeVondele
9045fdb227
Add depth condition
...
Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 103360 W: 26941 L: 26530 D: 49889
Ptnml(0-2): 291, 11964, 26770, 12353, 302
https://tests.stockfishchess.org/tests/view/68863547966ed85face24a6f
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 115128 W: 29734 L: 29258 D: 56136
Ptnml(0-2): 48, 12406, 32182, 12878, 50
https://tests.stockfishchess.org/tests/view/68864f867b562f5f7b7312f2
closes https://github.com/official-stockfish/Stockfish/pull/6184
Bench: 2972498
2025-07-28 19:49:05 +02:00
FauziAkram and Joost VandeVondele
4fcfb0b4b7
Tweak the logic for setting the improving flag
...
Tweak the logic for setting the improving flag when the static evaluation is significantly higher than alpha.
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 92320 W: 24057 L: 23664 D: 44599
Ptnml(0-2): 247, 10689, 23893, 11086, 245
https://tests.stockfishchess.org/tests/view/68860aba966ed85face248a1
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 281292 W: 72496 L: 71683 D: 137113
Ptnml(0-2): 135, 30289, 78995, 31082, 145
https://tests.stockfishchess.org/tests/view/6886168c966ed85face24962
closes https://github.com/official-stockfish/Stockfish/pull/6180
Bench: 3200439
2025-07-28 19:45:13 +02:00
pb00067 and Joost VandeVondele
402602a70d
Simplify static evaluation difference to move ordering logic
...
Passed STC simplification bounds
https://tests.stockfishchess.org/tests/view/686fcb091451bd6fb83082bc
LLR: 2.92 (-2.94,2.94) <-1.75,0.25>
Total: 762816 W: 196717 L: 197295 D: 368804
Ptnml(0-2): 2052, 90457, 196853, 90109, 1937
Passed LTC simplification bounds
https://tests.stockfishchess.org/tests/view/68808d316e17e7fa3939b35d
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 44736 W: 11499 L: 11303 D: 21934
Ptnml(0-2): 24, 4766, 12586, 4974, 18
closes https://github.com/official-stockfish/Stockfish/pull/6176
bench: 2684407
2025-07-28 19:40:15 +02:00
Guenther Demetz and Joost VandeVondele
b6082ba750
Simplify search functions according DRY principle
...
Passed STC non-regression bounds
https://tests.stockfishchess.org/tests/view/6870db4bfa93cf16d3bb286a
LLR: 3.00 (-2.94,2.94) <-1.75,0.25>
Total: 182016 W: 46735 L: 46673 D: 88608
Ptnml(0-2): 368, 19895, 50465, 19867, 413
closes https://github.com/official-stockfish/Stockfish/pull/6161
no functional change
2025-07-28 19:35:28 +02:00
Muzhen Gaming and Joost VandeVondele
90c83c381f
VVLTC Search Tune
...
alues were tuned with 125k VVLTC games.
Passed VVLTC 1st sprt:
https://tests.stockfishchess.org/tests/view/68865feb7b562f5f7b731341
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 39640 W: 10380 L: 10109 D: 19151
Ptnml(0-2): 5, 3556, 12424, 3833, 2
Passed VVLTC 2nd sprt:
https://tests.stockfishchess.org/tests/view/68864dfa7b562f5f7b7312ee
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 25972 W: 6807 L: 6537 D: 12628
Ptnml(0-2): 0, 2294, 8132, 2556, 4
closes https://github.com/official-stockfish/Stockfish/pull/6188
Bench: 3143696
2025-07-28 19:33:00 +02:00
aronpetkovski and Joost VandeVondele
a516b517d3
Simplify eval >= beta condition from NMP
...
It seems that now only checking if static eval is above beta by some margin is all that's necessary.
Passed Non-Regression STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 227264 W: 58430 L: 58421 D: 110413
Ptnml(0-2): 532, 26559, 59454, 26542, 545
https://tests.stockfishchess.org/tests/view/68763a77432ca24f6388c766
Passed Non-Regression LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 72048 W: 18622 L: 18455 D: 34971
Ptnml(0-2): 26, 7775, 20272, 7908, 43
https://tests.stockfishchess.org/tests/view/687c9f2b6e17e7fa3939b0c5
closes https://github.com/official-stockfish/Stockfish/pull/6175
Bench: 2759840
2025-07-24 10:38:13 +02:00
