Commit Graph
2836 Commits
Author SHA1 Message Date
Nonlinear2andJoost VandeVondele 4975b2bc6f Increase prior countermove bonus if TT move
Passed STC:
https://tests.stockfishchess.org/tests/view/678c4c8bf4dc0a8b4ae8db5c
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 273408 W: 71089 L: 70415 D: 131904
Ptnml(0-2): 937, 32466, 69229, 33130, 942

Passed LTC:
https://tests.stockfishchess.org/tests/view/678ccabdf4dc0a8b4ae8dd7a
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 148614 W: 38138 L: 37584 D: 72892
Ptnml(0-2): 97, 16450, 40689, 16944, 127

closes https://github.com/official-stockfish/Stockfish/pull/5809

Bench: 1582867
2025-01-25 20:27:11 +01:00
Stefan GeschwentnerandJoost VandeVondele 59c578ad28 Add move count based reduction.
Do less reduction which is linear increasing with move count (factor = 64).

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 191488 W: 49982 L: 49432 D: 92074
Ptnml(0-2): 731, 22523, 48614, 23217, 659
https://tests.stockfishchess.org/tests/view/678d0b29d63764e34db4904b

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 90582 W: 23150 L: 22717 D: 44715
Ptnml(0-2): 73, 9936, 24822, 10405, 55
https://tests.stockfishchess.org/tests/view/678d347cd63764e34db4916f

closes https://github.com/official-stockfish/Stockfish/pull/5807

Bench: 1803474
2025-01-25 20:23:33 +01:00
Joost VandeVondele 8e3e22b3d4 Replace depth increase condition with !opponentWorsening
Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 220544 W: 57417 L: 57399 D: 105728
Ptnml(0-2): 816, 26554, 55540, 26520, 842
https://tests.stockfishchess.org/tests/view/678970e38082388fa0cbfe02

Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 132600 W: 33868 L: 33760 D: 64972
Ptnml(0-2): 126, 14770, 36390, 14898, 116
https://tests.stockfishchess.org/tests/view/678accabc00c743bc9e9fc7f

closes https://github.com/official-stockfish/Stockfish/pull/5798

bench 1632964
2025-01-18 21:33:17 +01:00
Daniel MonroeandJoost VandeVondele f00d91f8ac Refine probcut
Allow probcut for depth 3 and disable deeper verification search when it would simply repeat the qsearch.

Passed STC
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 283232 W: 74450 L: 73760 D: 135022
Ptnml(0-2): 1052, 33780, 71349, 34296, 1139
https://tests.stockfishchess.org/tests/view/67843b58460e2910c51ddcc6

Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 339654 W: 86845 L: 85893 D: 166916
Ptnml(0-2): 298, 37734, 92802, 38704, 289
https://tests.stockfishchess.org/tests/view/678aa722c00c743bc9e9face

closes https://github.com/official-stockfish/Stockfish/pull/5797

bench 1288648
2025-01-18 21:27:42 +01:00
Shawn XuandJoost VandeVondele 738ac2a100 tuned TM values
Tuned 70k games at 240+2.4 th 2: https://tests.stockfishchess.org/tests/view/6783b1b16ddf09c0b4b703f5

Failed STC:
LLR: -2.93 (-2.94,2.94) <0.00,2.00>
Total: 491872 W: 128260 L: 127804 D: 235808
Ptnml(0-2): 1579, 55449, 131572, 55609, 1727
https://tests.stockfishchess.org/tests/view/6785a045460e2910c51de4b8

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 154824 W: 39315 L: 38874 D: 76635
Ptnml(0-2): 110, 15809, 45147, 16222, 124
https://tests.stockfishchess.org/tests/view/678ac722c00c743bc9e9fc35

Passed VLTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 77404 W: 19825 L: 19452 D: 38127
Ptnml(0-2): 18, 7262, 23765, 7643, 14
https://tests.stockfishchess.org/tests/view/678b2a98c00c743bc9ea048c

closes https://github.com/official-stockfish/Stockfish/pull/5796

No functional change
2025-01-18 21:24:01 +01:00
FauziAkramandJoost VandeVondele c94bcf62e4 Moving up the if position is or has been on the PV reduction
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 29664 W: 7880 L: 7570 D: 14214
Ptnml(0-2): 93, 3487, 7390, 3741, 121
https://tests.stockfishchess.org/tests/view/678ac957c00c743bc9e9fc3f

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 81354 W: 20903 L: 20487 D: 39964
Ptnml(0-2): 66, 9003, 22123, 9419, 66
https://tests.stockfishchess.org/tests/view/678ad359c00c743bc9e9fcfa

closes https://github.com/official-stockfish/Stockfish/pull/5794

Bench: 1414638
2025-01-18 21:18:48 +01:00
Michael ChalyandJoost VandeVondele 7701d0b3c4 Introduce one more continuation history
This one is counter counter counter history - with really low update value and divided by 3 in movepicker unlike the other ones.

Passed STC:
https://tests.stockfishchess.org/tests/view/67861495460e2910c51de720
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 44352 W: 11699 L: 11370 D: 21283
Ptnml(0-2): 156, 5098, 11361, 5383, 178

Passed LTC:
https://tests.stockfishchess.org/tests/view/6786e89e3b8f206a2696b646
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 432660 W: 110355 L: 109207 D: 213098
Ptnml(0-2): 381, 48214, 118039, 49268, 428

closes https://github.com/official-stockfish/Stockfish/pull/5792

Bench: 1491837
2025-01-18 21:04:55 +01:00
Nonlinear2andJoost VandeVondele b392ac76db Increase history bonus of TT moves
Passed STC:
https://tests.stockfishchess.org/tests/view/678807653b8f206a2696b78b
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 42208 W: 11113 L: 10783 D: 20312
Ptnml(0-2): 148, 4919, 10651, 5227, 159

Passed LTC:
https://tests.stockfishchess.org/tests/view/6788a8463b8f206a2696b956
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 122886 W: 31454 L: 30952 D: 60480
Ptnml(0-2): 105, 13567, 33619, 14025, 127

closes https://github.com/official-stockfish/Stockfish/pull/5791

Bench: 1760081
2025-01-18 21:02:04 +01:00
Shawn XuandJoost VandeVondele ccbd060b01 simplify razoring
Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 93056 W: 24215 L: 24054 D: 44787
Ptnml(0-2): 364, 11085, 23470, 11244, 365
https://tests.stockfishchess.org/tests/view/67883a5d3b8f206a2696b804

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 66564 W: 16971 L: 16794 D: 32799
Ptnml(0-2): 56, 7403, 18192, 7570, 61
https://tests.stockfishchess.org/tests/view/6789ffa78082388fa0cbfe95

closes https://github.com/official-stockfish/Stockfish/pull/5788

bench 1500649
2025-01-18 20:54:55 +01:00
Daniel MonroeandJoost VandeVondele a944f08225 retroactive reduction decrease if eval improves
If the previous reduction was large but the static eval improves then increase the search depth. This patch looks at the next node when calculating the reduction, something I don't think has been done before and which can probably used for further elo gaining patches.

Passed STC
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 55936 W: 14813 L: 14462 D: 26661
Ptnml(0-2): 220, 6565, 14094, 6822, 267
https://tests.stockfishchess.org/tests/view/67845b70460e2910c51ddcff

Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 189468 W: 48411 L: 47773 D: 93284
Ptnml(0-2): 180, 20801, 52131, 21445, 177
https://tests.stockfishchess.org/tests/view/6784e2cb460e2910c51ddf86

closes https://github.com/official-stockfish/Stockfish/pull/5785

bench: 1512884
2025-01-18 20:50:04 +01:00
DisservinandJoost VandeVondele 4c2241089d Remove addition of 1ms to all timestamps
The +1 was a quick fix to avoid the division by zero, a more correct approach is to use 1ms as the minimum reported timestamp to avoid a division by zero.
Later timestamps no longer include an additional 1ms.

closes https://github.com/official-stockfish/Stockfish/pull/5778

No functional change
2025-01-18 20:32:00 +01:00
Daniel MonroeandJoost VandeVondele 5868b4cb58 remove eval== staticeval check in fut pruning
Simplify corrplexity in futility margin
Don't check that staticEval == eval when applying the corrplexity-based adjustment in futility pruning.

Passed Simplification STC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 121760 W: 31640 L: 31512 D: 58608
Ptnml(0-2): 349, 14400, 31289, 14458, 384
https://tests.stockfishchess.org/tests/view/6780c4109168c8bf30927777

Passed Simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 134772 W: 34245 L: 34140 D: 66387
Ptnml(0-2): 94, 14869, 37350, 14984, 89
https://tests.stockfishchess.org/tests/view/6782d6ea6ddf09c0b4b6dd36

closes https://github.com/official-stockfish/Stockfish/pull/5776

Bench: 1487627
2025-01-18 20:25:59 +01:00
Carlos EsparzaandJoost VandeVondele aaafaaecf2 prefetch in do_move()
this allows removing Position::key_after()

STC
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 24960 W: 6556 L: 6336 D: 12068
Ptnml(0-2): 59, 2554, 7056, 2730, 81

LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 115080 W: 29319 L: 29204 D: 56557
Ptnml(0-2): 51, 10736, 35864, 10825, 64

STC with 2MB hash
LLR: 3.04 (-2.94,2.94) <-1.75,0.25>
Total: 182176 W: 46998 L: 46932 D: 88246
Ptnml(0-2): 526, 19711, 50544, 19785, 522

LTC with 8MB hash
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 441180 W: 111557 L: 111746 D: 217877
Ptnml(0-2): 229, 39698, 140929, 39501, 233

closes https://github.com/official-stockfish/Stockfish/pull/5770

bench: 1379150
2025-01-18 20:19:53 +01:00
FauziAkramandDisservin c085670b84 Increase the depth margin
Tested at VVLTC against the passed patches.

Test 1 against PR5764
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 167260 W: 43053 L: 42521 D: 81686
Ptnml(0-2): 7, 15272, 52542, 15800, 9
https://tests.stockfishchess.org/tests/view/6782ef196ddf09c0b4b6e780

Test 2 against PR5765
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 300012 W: 77364 L: 76771 D: 145877
Ptnml(0-2): 22, 27555, 94256, 28154, 19
https://tests.stockfishchess.org/tests/view/678366446ddf09c0b4b7028c

closes https://github.com/official-stockfish/Stockfish/pull/5768

Bench: 1379150
2025-01-12 21:36:39 +01:00
Viren6andDisservin e2612f9a29 Introduce Correction History Quad Extensions
Also modifies the double and triple extension margins with the correction history adjustment.

STC Elo Estimate:
Elo: -4.40 ± 1.4 (95%) LOS: 0.0%
Total: 60000 W: 15230 L: 15990 D: 28780
Ptnml(0-2): 264, 7495, 15168, 6883, 190
nElo: -8.48 ± 2.8 (95%) PairsRatio: 0.91
https://tests.stockfishchess.org/tests/view/6783a3786ddf09c0b4b703a1

Passed 1st VVLTC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 35736 W: 9354 L: 9088 D: 17294
Ptnml(0-2): 4, 3191, 11212, 3457, 4
https://tests.stockfishchess.org/tests/view/6783a3336ddf09c0b4b7039b

Passed 2nd VVLTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 36394 W: 9515 L: 9225 D: 17654
Ptnml(0-2): 1, 3271, 11364, 3559, 2
https://tests.stockfishchess.org/tests/view/678395e26ddf09c0b4b70345

closes https://github.com/official-stockfish/Stockfish/pull/5767

Bench: 1567166
2025-01-12 21:36:39 +01:00
Muzhen GamingandDisservin 93edf7a74c VVLTC Search Tune
Values were tuned with 118k VVLTC games.

Tested against #5764.

Passed VVLTC 1st sprt:
https://tests.stockfishchess.org/tests/view/678331226ddf09c0b4b6fd78
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 43556 W: 11219 L: 10942 D: 21395
Ptnml(0-2): 2, 3975, 13549, 4248, 4

Passed VVLTC 2nd sprt:
https://tests.stockfishchess.org/tests/view/67834aa06ddf09c0b4b6fe34
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 37150 W: 9577 L: 9285 D: 18288
Ptnml(0-2): 2, 3344, 11593, 3632, 4

closes https://github.com/official-stockfish/Stockfish/pull/5765

Bench: 1258128
2025-01-12 21:36:31 +01:00
Michael ChalyandDisservin 8b32e4825f Make IIR less aggressive
This patch is an elo gaining simplification which gains elo at longer time controls.
Patch disallows IIR for cutNodes with existing tt moves as well as makes
IIR for pv nodes less aggressive, basiclally confirming suspected
scaling patterns for this heuristic.

Result of 50k games STC run:
https://tests.stockfishchess.org/tests/view/678304676ddf09c0b4b6f9f9
Elo: -2.93 ± 1.6 (95%) LOS: 0.0%
Total: 50000 W: 12718 L: 13140 D: 24142
Ptnml(0-2): 189, 6087, 12835, 5735, 154
nElo: -5.71 ± 3.0 (95%) PairsRatio: 0.94

Passed VVLTC SPRT with STC bounds:
https://tests.stockfishchess.org/tests/view/6782eb1a6ddf09c0b4b6e6b0
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 150292 W: 38868 L: 38458 D: 72966
Ptnml(0-2): 19, 13890, 46907, 14322, 8

Passed VVLTC SPRT with LTC bounds:
https://tests.stockfishchess.org/tests/view/6782d8d96ddf09c0b4b6df18
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 153388 W: 39791 L: 39285 D: 74312
Ptnml(0-2): 13, 13924, 48311, 14436, 10

closes https://github.com/official-stockfish/Stockfish/pull/5763

Bench: 1507606
2025-01-12 21:25:36 +01:00
mstemberaandDisservin b84c8807a3 Optimize attackers_to()
https://tests.stockfishchess.org/tests/view/6782decb6ddf09c0b4b6e1b0
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 105920 W: 27571 L: 27181 D: 51168
Ptnml(0-2): 284, 10808, 30403, 11164, 301

- If we only need to know if attackers exist we can skip some
  calculations.
- Also calculating slider/magic attackers first is better because the
  double lookup is slow due to memory latency.
- I also included a couple of very minor cleanups in search that
  probably don't warrant their own PR but I can open separately if
  that's better.

closes https://github.com/official-stockfish/Stockfish/pull/5762

No functional change
2025-01-12 21:24:44 +01:00
Shawn XuandDisservin 921361829a Simplify away capthist bonus in Probcut
The explicit bonus has been obsoleted with the introduction of #5695

Passed Non-regression STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 132832 W: 34519 L: 34403 D: 63910
Ptnml(0-2): 430, 15754, 33931, 15872, 429
https://tests.stockfishchess.org/tests/view/678158c49168c8bf30927834

Passed Non-regression LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 123492 W: 31426 L: 31309 D: 60757
Ptnml(0-2): 79, 13705, 34051, 13842, 69
https://tests.stockfishchess.org/tests/view/6782b07e6ddf09c0b4b6dbb7

closes https://github.com/official-stockfish/Stockfish/pull/5761

Bench: 1180439
2025-01-12 21:23:29 +01:00
Shawn XuandDisservin 28c07fb456 Simplify Probcut Condition
Rebased and properly guarded #5720

Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 179616 W: 45764 L: 45706 D: 88146
Ptnml(0-2): 125, 19665, 50162, 19739, 117
https://tests.stockfishchess.org/tests/view/677590531a2f267f20548b82

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 445728 W: 113467 L: 113682 D: 218579
Ptnml(0-2): 331, 49226, 123900, 49141, 266
https://tests.stockfishchess.org/tests/view/67734f351a2f267f205489d9

closes https://github.com/official-stockfish/Stockfish/pull/5758

Bench: 1180421
2025-01-12 21:18:39 +01:00
pb00067andDisservin c88a5b3950 Simplify away hint for common parent position at probcut
Since it's introduction at probcut step the nnue network has changed
substantially and now it no longer seems useful.

Passed non-regression test at STC
https://tests.stockfishchess.org/tests/view/675fe27986d5ee47d9542d86
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 118656 W: 30732 L: 30609 D: 57315
Ptnml(0-2): 319, 12767, 33049, 12858, 335

N.B.: It may be useful to reintroduce it here at probcut if we know that
a node that was cut away previously now has to be explored. Exploring
new ground will deliver no tt-hits so in this case the hint for common
parent position might be useful.

No functional change
2025-01-12 21:15:35 +01:00
Shawn XuandDisservin 403a5e100b Simplify Fail-Low Bonus
Passed Non-regression STC:
LLR: 2.92 (-2.94,2.94) <-1.75,0.25>
Total: 66592 W: 17426 L: 17239 D: 31927
Ptnml(0-2): 208, 7812, 17109, 7919, 248
https://tests.stockfishchess.org/tests/view/6774e1711a2f267f20548b22

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 179616 W: 45764 L: 45706 D: 88146
Ptnml(0-2): 125, 19665, 50162, 19739, 117
https://tests.stockfishchess.org/tests/view/677590531a2f267f20548b82

closes https://github.com/official-stockfish/Stockfish/pull/5751

Bench: 1310158
2025-01-12 21:14:11 +01:00
Shawn XuandDisservin 5370c3035e Refactor Stats Array
* Limit use of `StatsEntry` wrapper to arithmetic types
* Generalize `Stats` to `MultiArray` by discarding the template parameter `D`
* Allow `MultiArray::fill` to take any type assignable to element type
* Remove now-unused operator overloads on `StatsEntry`

closes https://github.com/official-stockfish/Stockfish/pull/5750

No functional change
2025-01-12 21:13:14 +01:00
Shawn XuandDisservin d1a1ff4f17 Simplify Razoring
Passed Non-regression STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 95584 W: 24906 L: 24750 D: 45928
Ptnml(0-2): 285, 11227, 24632, 11343, 305
https://tests.stockfishchess.org/tests/view/675e0ed286d5ee47d95429ee

Passed Non-regression LTC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 191292 W: 48637 L: 48589 D: 94066
Ptnml(0-2): 97, 21061, 53276, 21121, 91
https://tests.stockfishchess.org/tests/view/675f08c686d5ee47d9542be3

closes https://github.com/official-stockfish/Stockfish/pull/5724

Bench: 1286274
2025-01-12 21:11:27 +01:00
Daniel MonroeandDisservin c76c179361 Remove non-functional std::min()
closes https://github.com/official-stockfish/Stockfish/pull/5749

No functional change
2025-01-06 00:48:05 +01:00
Daniel MonroeandDisservin 1611b9c940 Corrplexity for futility pruning
Add corrhist-based term to futility margin

Inspired by a recent patch of Shawn Xu, this tweak increases the margin
over beta needed to futility prune based on the correction history, with
an offset.

Passed STC
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 545504 W: 141957 L: 140885 D: 262662
Ptnml(0-2): 1829, 64226, 139551, 65336, 1810
https://tests.stockfishchess.org/tests/view/67634a8386d5ee47d95439db

Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 125994 W: 32199 L: 31695 D: 62100
Ptnml(0-2): 97, 13742, 34798, 14280, 80
https://tests.stockfishchess.org/tests/view/6765cf9986d5ee47d9544217

closes https://github.com/official-stockfish/Stockfish/pull/5748

Bench: 999324
2025-01-06 00:46:30 +01:00
Shawn XuandDisservin 5488dd2f91 Update Copyright Year
closes https://github.com/official-stockfish/Stockfish/pull/5747

No functional change
2025-01-06 00:45:28 +01:00
Shawn XuandDisservin 78b5733939 Simplify post-lmr conthist bonus
Passed Non-regression STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 49184 W: 12735 L: 12528 D: 23921
Ptnml(0-2): 134, 5746, 12647, 5909, 156
https://tests.stockfishchess.org/tests/view/6765cd2e86d5ee47d954420e

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 177270 W: 45227 L: 45166 D: 86877
Ptnml(0-2): 132, 19498, 49302, 19583, 120
https://tests.stockfishchess.org/tests/view/676721fd86d5ee47d9544489

closes https://github.com/official-stockfish/Stockfish/pull/5734

Bench: 1042099
2025-01-06 00:43:37 +01:00
Michael ChalyandDisservin 03e4cde729 Allow Pv nodes at certain conditions to spawn zero window searches deeper than default
In current case it's allowed if there is no best move.

Passed STC:
https://tests.stockfishchess.org/tests/view/67640fd586d5ee47d9543d5a
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 392480 W: 102038 L: 101192 D: 189250
Ptnml(0-2): 1303, 46287, 100253, 47055, 1342

Passed LTC:
https://tests.stockfishchess.org/tests/view/67671a4686d5ee47d9544476
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 128616 W: 32941 L: 32433 D: 63242
Ptnml(0-2): 84, 13997, 35634, 14513, 80

closes https://github.com/official-stockfish/Stockfish/pull/5733

Bench: 1095871
2025-01-06 00:40:05 +01:00
Michael ChalyandDisservin 79261bec59 Simplify away reductions adjustment for multithreaded search
Seem to no longer bring measurable benefit.

Passed STC SMP simplification:
https://tests.stockfishchess.org/tests/view/6753561a86d5ee47d954151f
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 38000 W: 9864 L: 9656 D: 18480
Ptnml(0-2): 53, 4177, 10320, 4409, 41

Passed LTC SMP simplification:
https://tests.stockfishchess.org/tests/view/6753d75f86d5ee47d9541669
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 258674 W: 66314 L: 66335 D: 126025
Ptnml(0-2): 77, 26957, 75303, 26910, 90

Passed 16 threads LTC simplification:
https://tests.stockfishchess.org/tests/view/675a066286d5ee47d9542296
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 221804 W: 56950 L: 56936 D: 107918
Ptnml(0-2): 34, 21491, 67839, 21503, 35

closes https://github.com/official-stockfish/Stockfish/pull/5729

Bench: 1294909
2024-12-22 15:28:15 +01:00
Disservin 4bc2a24245 Workaround for clang-format bug
closes https://github.com/official-stockfish/Stockfish/pull/5728

No functional change
2024-12-22 15:27:40 +01:00
Shawn XuandDisservin e7e78aa09e Adjust LMR with correction history
A positive constant increase in base reduction is applied to counter the
decrease in average reduction from this tweak.

Passed STC:
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 109216 W: 28415 L: 27989 D: 52812
Ptnml(0-2): 310, 12848, 27911, 13184, 355
https://tests.stockfishchess.org/tests/view/6760bb0e86d5ee47d9542f26

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 66918 W: 17073 L: 16694 D: 33151
Ptnml(0-2): 33, 7175, 18666, 7550, 35
https://tests.stockfishchess.org/tests/view/6761e10f86d5ee47d95431fa

closes https://github.com/official-stockfish/Stockfish/pull/5727

Bench: 1294909
2024-12-22 15:26:39 +01:00
FauziAkramandDisservin a04b07265f Make reductionScale smoother
Making the second part of the formula smoother, changing it to a linear
function, increasing steadily as reductionScale increases and at the
same time, it should be a little bit simpler, therefore the
simplification bounds.

Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 83040 W: 21493 L: 21322 D: 40225
Ptnml(0-2): 252, 9848, 21209, 9899, 312
https://tests.stockfishchess.org/tests/view/6762145486d5ee47d9543242

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 230124 W: 58485 L: 58478 D: 113161
Ptnml(0-2): 175, 25620, 63484, 25589, 194
https://tests.stockfishchess.org/tests/view/6762d4ef86d5ee47d9543367

closes https://github.com/official-stockfish/Stockfish/pull/5725

Bench: 1204658
2024-12-22 15:24:09 +01:00
Disservin 2dc47e4345 Cleanup Evaluate Calls
Makes code a bit easier to read as well.

closes https://github.com/official-stockfish/Stockfish/pull/5722

No functional change
2024-12-22 15:19:53 +01:00
Daniel MonroeandDisservin ba145332c9 Remove time reduction for recaptures
Passed simplification STC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 54016 W: 14098 L: 13902 D: 26016
Ptnml(0-2): 165, 5797, 14919, 5931, 196
https://tests.stockfishchess.org/tests/view/6758a90486d5ee47d954201e

Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 296940 W: 75631 L: 75689 D: 145620
Ptnml(0-2): 145, 28928, 90384, 28866, 147
https://tests.stockfishchess.org/tests/view/6758df7a86d5ee47d9542091

closes https://github.com/official-stockfish/Stockfish/pull/5719

Bench: 1148169
2024-12-22 15:17:55 +01:00
Shawn XuandDisservin e770b55f7f Remove Extraneous Parenthesis
No longer needed after
https://github.com/official-stockfish/Stockfish/pull/5667.

closes https://github.com/official-stockfish/Stockfish/pull/5717

No functional change
2024-12-22 15:17:33 +01:00
Shawn XuandDisservin b822fdf2f2 Tune histories
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 268736 W: 70080 L: 69421 D: 129235
Ptnml(0-2): 831, 31795, 68460, 32448, 834
https://tests.stockfishchess.org/tests/view/6750778886d5ee47d9540e7c

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 505356 W: 129145 L: 127868 D: 248343
Ptnml(0-2): 307, 54901, 140959, 56230, 281
https://tests.stockfishchess.org/tests/view/675367de86d5ee47d9541536

closes https://github.com/official-stockfish/Stockfish/pull/5712

Bench: 1148169
2024-12-22 15:14:22 +01:00
Nonlinear2andGitHub cf10644d6e Fix duplicate code (#5711)
closes https://github.com/official-stockfish/Stockfish/pull/5711

No functional change
2024-12-08 22:24:29 +01:00
Michael ChalyandDisservin afaf3a0f2a Refine statscore for captures
Continuation of previous attempts there.
Now instead of using capture history with a static offset also add the
value of the captured piece in the same way at it is used in movepicker.

Passed STC:
https://tests.stockfishchess.org/tests/view/674aa3d386d5ee47d95404aa
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 116480 W: 30433 L: 29999 D: 56048
Ptnml(0-2): 361, 13720, 29662, 14118, 379

Passed LTC:
https://tests.stockfishchess.org/tests/view/674c4b2d86d5ee47d954073f
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 133542 W: 34365 L: 33847 D: 65330
Ptnml(0-2): 78, 14585, 36934, 15089, 85

closes https://github.com/official-stockfish/Stockfish/pull/5706

Bench: 934447
2024-12-08 19:57:59 +01:00
Shawn XuandDisservin 6a8478c6ad Simplify Prior Capture Countermove Bonus
Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 184032 W: 47626 L: 47568 D: 88838
Ptnml(0-2): 590, 21808, 47238, 21714, 666
https://tests.stockfishchess.org/tests/view/67412c7686d5ee47d953f743

Passed Non-regression LTC:
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 169218 W: 43395 L: 43323 D: 82500
Ptnml(0-2): 302, 18567, 46791, 18655, 294
https://tests.stockfishchess.org/tests/view/6743b7e086d5ee47d953f9a6

closes https://github.com/official-stockfish/Stockfish/pull/5701

Bench: 1130692
2024-12-08 19:55:10 +01:00
pb00067andDisservin 713000c517 Same weight for black and white nonPawnCorrection history
Since we don't have color dependent parameters in NNUE eval, it also has
no sense IMO to have color dependent parameters in correction histories.

Ideally a fixed depth search on a single thread should be determistic,
so delivering the same result (move) if we just flip colors on the
board.

Patch replaces 2 parameters (122 and 185) with just one value 154 (= the avg of the two).

Passed STC-non regression
https://tests.stockfishchess.org/tests/view/6740a63286d5ee47d953f656
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 122336 W: 31499 L: 31372 D: 59465
Ptnml(0-2): 336, 14535, 31301, 14658, 338

Passed LTC-non regression
https://tests.stockfishchess.org/tests/view/67419bae86d5ee47d953f7b6
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 101400 W: 25870 L: 25731 D: 49799
Ptnml(0-2): 78, 11109, 28166, 11290, 57

closes https://github.com/official-stockfish/Stockfish/pull/5698

Bench: 1215483
2024-12-08 19:52:16 +01:00
FauziAkramandDisservin d5a36a3c92 Simplify probCutBeta formula
After recent changes to the improving definition, seems like there is no
need anymore to keep opponentWorsening in the probCutBeta formula.

Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 214272 W: 55566 L: 55541 D: 103165
Ptnml(0-2): 620, 25540, 54817, 25513, 646
https://tests.stockfishchess.org/tests/view/6735243d86d5ee47d953eaea

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 126708 W: 32329 L: 32216 D: 62163
Ptnml(0-2): 68, 13986, 35123, 14119, 58
https://tests.stockfishchess.org/tests/view/67393cf686d5ee47d953ef99

closes https://github.com/official-stockfish/Stockfish/pull/5697

Bench: 983067
2024-12-08 19:49:01 +01:00
Nonlinear2andDisservin da82942b54 Add functions to check for decisive scores
Thanks to peregrineshahin and robbyrobbyrob for their suggestions.

closes https://github.com/official-stockfish/Stockfish/pull/5696

No functional change
2024-12-08 19:48:49 +01:00
Nonlinear2andDisservin 57e06be71f Add functions to check for decisive scores
Thanks to peregrineshahin and robbyrobbyrob for their suggestions.

closes https://github.com/official-stockfish/Stockfish/pull/5696

No functional change
2024-12-08 19:47:02 +01:00
Daniel MonroeandDisservin 70bb317afe Bonus for a prior capture that causes a fail low.
This tweak adds a bonus equal to twice the stat_bonus for the current depth for a prior capture that caused a fail high, similar to the prior countermove bonus we currently have.

Passed STC
https://tests.stockfishchess.org/tests/view/673bc14b86d5ee47d953f1f2
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 105824 W: 27538 L: 27118 D: 51168
Ptnml(0-2): 358, 12370, 27024, 12814, 346

Passed LTC
https://tests.stockfishchess.org/tests/view/673ccbff86d5ee47d953f2d9
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 134502 W: 34340 L: 33820 D: 66342
Ptnml(0-2): 102, 14634, 37229, 15214, 72

closes https://github.com/official-stockfish/Stockfish/pull/5695

Bench: 1107054
2024-12-08 19:46:07 +01:00
Daniel MonroeandDisservin fb6be17ad4 Simplify statscore at captures
Simplify statscores for captures, setting them to 0

A recent tweak of Vizvezdenec finds substantial elo gain from giving
captures a separate statscore, which is used mainly for reductions. The
idea is that the old combination of quiet histories was inappropriate
and that a value based on the capture history is more suitable. This
simplification sets the statscore for captures to 0, suggesting that the
elo gain came from rectifying the quiet history/capture mismatch.

Passed STC (against a slightly older version of Viz's patch)
https://tests.stockfishchess.org/tests/view/673ac6e286d5ee47d953f0ec
LR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 57312 W: 14872 L: 14672 D: 27768
Ptnml(0-2): 152, 6761, 14649, 6923, 171

Passed LTC (against Viz's newest patch)
https://tests.stockfishchess.org/tests/view/673cd00686d5ee47d953f2db
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 88236 W: 22510 L: 22358 D: 43368
Ptnml(0-2): 70, 9530, 24745, 9724, 49

closes https://github.com/official-stockfish/Stockfish/pull/5691

Bench: 959947
2024-11-22 23:34:15 +01:00
Shawn XuandDisservin 4fcd78ceb4 Simplify Probcut Bonus
Passed STC:
LLR: 2.99 (-2.94,2.94) <-1.75,0.25>
Total: 172288 W: 44656 L: 44580 D: 83052
Ptnml(0-2): 507, 20650, 43782, 20670, 535
https://tests.stockfishchess.org/tests/view/673b74f986d5ee47d953f1a3

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 94596 W: 24098 L: 23953 D: 46545
Ptnml(0-2): 57, 10322, 26393, 10471, 55
https://tests.stockfishchess.org/tests/view/673d191886d5ee47d953f337

closes https://github.com/official-stockfish/Stockfish/pull/5688

Bench: 1031022
2024-11-22 23:31:34 +01:00
Michael ChalyandDisservin cd3c13a883 Further tweak statscore for captures
Even lower offset.

Passed STC:
https://tests.stockfishchess.org/tests/view/673a66d786d5ee47d953f070
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 63776 W: 16570 L: 16216 D: 30990
Ptnml(0-2): 178, 7371, 16478, 7641, 220

Passed LTC:
https://tests.stockfishchess.org/tests/view/673b2e2a86d5ee47d953f14b
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 156960 W: 39999 L: 39435 D: 77526
Ptnml(0-2): 96, 16965, 43803, 17511, 105

closes https://github.com/official-stockfish/Stockfish/pull/5686

Bench: 867931
2024-11-22 23:29:37 +01:00
Guenther DemetzandDisservin d29c8bd5d4 Rewrite of 'Adjust correction history' condition
Current condition is convoluted and hard to understand because of
several negations. Also added 2 comments to make the concept behind the
condition better understandable.

closes https://github.com/official-stockfish/Stockfish/pull/5685

No functional change
2024-11-22 23:24:15 +01:00
FauziAkramandDisservin 0282edc0b0 Simplify bonus formula
Give full bonus instead of half.

Passed STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 23872 W: 6254 L: 6018 D: 11600
Ptnml(0-2): 80, 2691, 6152, 2939, 74
https://tests.stockfishchess.org/tests/view/673b709686d5ee47d953f19d

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 42894 W: 10924 L: 10725 D: 21245
Ptnml(0-2): 30, 4592, 12011, 4777, 37
https://tests.stockfishchess.org/tests/view/673bb50386d5ee47d953f1eb

closes https://github.com/official-stockfish/Stockfish/pull/5683

Bench: 836558
2024-11-22 23:23:42 +01:00