Stockfish Development Versions are build automatically if there are changes on the master branch in the git repository (https://github.com/official-stockfish/Stockfish). Use it at your own risk.
They are compiled with gcc 11.2/mingw 10 on Ubuntu 22.04.

Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: cj5716
Date: Sat Dec 2 11:45:38 2023 +0100
Timestamp: 1701513938

Remove recaptures stage in qsearch

Simplify an old commit
https://github.com/official-stockfish/Stockfish/commit/72760c05c64d1fb2bb71c2ac54acfbeecf513b87.

Search is not stuck on the test position given
r1n1n1b1/1P1P1P1P/1N1N1N2/2RnQrRq/2pKp3/3BNQbQ/k7/4Bq2 w - - 0 1

Passed STC:
https://tests.stockfishchess.org/tests/view/6567050d136acbc573550919
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 236160 W: 59475 L: 59475 D: 117210 Elo +0.00
Ptnml(0-2): 841, 28266, 59816, 28366, 791

Passed LTC:
https://tests.stockfishchess.org/tests/view/6567d133136acbc573551c78
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 201690 W: 49630 L: 49593 D: 102467 Elo +0.06
Ptnml(0-2): 128, 23214, 54122, 23255, 126

closes https://github.com/official-stockfish/Stockfish/pull/4896

Bench: 1604361
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Taras Vuk
Date: Sat Dec 2 11:41:31 2023 +0100
Timestamp: 1701513691

Skip LMR for 2nd move at the root only

This patch reverts commit by Vizvezdenec:
https://github.com/official-stockfish/Stockfish/commit/27139dedac14af400f5b18e2ab50aca3f8cf0e33

Passed STC:
https://tests.stockfishchess.org/tests/view/65660b4a136acbc57354f13d
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 301952 W: 76271 L: 76344 D: 149337 Elo -0.08
Ptnml(0-2): 1053, 36293, 76348, 36238, 1044

Passed LTC:
https://tests.stockfishchess.org/tests/view/656738ab136acbc573550e39
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 25050 W: 6283 L: 6063 D: 12704 Elo +3.05
Ptnml(0-2): 10, 2756, 6775, 2972, 12

closes https://github.com/official-stockfish/Stockfish/pull/4895

Bench: 1722961
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Sat Dec 2 11:40:36 2023 +0100
Timestamp: 1701513636

Simplify quietMoveMalus malus

Use a simple depth instead of depth + 1 in the quietMoveMalus formula.

Passed STC:
https://tests.stockfishchess.org/tests/view/65636bf0136acbc57354b662
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 105248 W: 26680 L: 26532 D: 52036 Elo +0.49
Ptnml(0-2): 409, 12590, 26481, 12732, 412

Passed LTC:
https://tests.stockfishchess.org/tests/view/6563b5db136acbc57354bcab
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 204204 W: 50200 L: 50166 D: 103838 Elo +0.06
Ptnml(0-2): 123, 23331, 55145, 23395, 108

closes https://github.com/official-stockfish/Stockfish/pull/4893

Bench: 1717495
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: cj5716
Date: Sat Dec 2 11:38:18 2023 +0100
Timestamp: 1701513498

Simplify promotion move generation

closes https://github.com/official-stockfish/Stockfish/pull/4892

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Sat Dec 2 11:35:28 2023 +0100
Timestamp: 1701513328

Simplify doDeeperSearch

Removing dependence on d simplifies the doDeeperSearch formula and eliminates a
variable that is not necessary in this context.

Passed STC:
https://tests.stockfishchess.org/tests/view/65647980136acbc57354c9f6
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 37440 W: 9558 L: 9334 D: 18548 Elo +2.08
Ptnml(0-2): 127, 4439, 9375, 4641, 138

Passed LTC:
https://tests.stockfishchess.org/tests/view/6564c3f0136acbc57354d126
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 113946 W: 27993 L: 27864 D: 58089 Elo +0.39
Ptnml(0-2): 67, 12975, 30783, 13058, 90

closes https://github.com/official-stockfish/Stockfish/pull/4888

Bench: 1427733
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Muzhen Gaming
Date: Sat Dec 2 11:30:47 2023 +0100
Timestamp: 1701513047

Simplify move history reduction

Recent VLTC search tuning has suggested that the depth limit can be increased
by a lot. This patch simplifies away the depth-based bonus from statScore
reduction, making the divisor a constant.

Passed STC:
https://tests.stockfishchess.org/tests/view/656201f5136acbc573549791
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 91520 W: 23130 L: 22967 D: 45423 Elo +0.62
Ptnml(0-2): 282, 10947, 23141, 11106, 284

Passed LTC:
https://tests.stockfishchess.org/tests/view/6562b43a136acbc57354a581
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 352902 W: 86796 L: 86917 D: 179189 Elo -0.12
Ptnml(0-2): 190, 40227, 95741, 40100, 193

closes https://github.com/official-stockfish/Stockfish/pull/4886

Bench: 1297179
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Stefan Geschwentner
Date: Sat Dec 2 11:23:15 2023 +0100
Timestamp: 1701512595

Simplify history update.

Removal of the slowdown factor from the history update formula with
corresponding adjustment of the stat bonus used in the search.

Passed STC:
https://tests.stockfishchess.org/tests/view/655e1079136acbc573544744
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 128096 W: 32355 L: 32235 D: 63506 Elo +0.33
Ptnml(0-2): 466, 15187, 32573, 15405, 417

Passed LTC:
https://tests.stockfishchess.org/tests/view/655f4e60136acbc573546266
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 50652 W: 12653 L: 12459 D: 25540 Elo +1.33
Ptnml(0-2): 28, 5666, 13751, 5846, 35

closes https://github.com/official-stockfish/Stockfish/pull/4883

Bench: 1303857
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Mon Nov 20 19:10:38 2023 +0100
Timestamp: 1700503838

Reformat some comments

Tests used to derive some Elo worth comments:

https://tests.stockfishchess.org/tests/view/653cf6b7cc309ae83956263a
https://tests.stockfishchess.org/tests/view/655250b7136acbc573534711
https://tests.stockfishchess.org/tests/view/65525767136acbc5735347b9
https://tests.stockfishchess.org/tests/view/65525aa1136acbc573534801

closes https://github.com/official-stockfish/Stockfish/pull/4879

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Mon Nov 20 19:00:47 2023 +0100
Timestamp: 1700503247

Remove doEvenDeeperSearch

Passed STC:
LLR: 2.98 (-2.94,2.94) <-1.75,0.25>
Total: 51040 W: 13014 L: 12804 D: 25222 Elo +1.43
Ptnml(0-2): 166, 6032, 12917, 6236, 169
https://tests.stockfishchess.org/tests/view/65525aa1136acbc573534801

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 165168 W: 40863 L: 40789 D: 83516 Elo +0.16
Ptnml(0-2): 73, 18783, 44792, 18869, 67
https://tests.stockfishchess.org/tests/view/65535af5136acbc573535c84

closes https://github.com/official-stockfish/Stockfish/pull/4880

Bench: 1477007
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Mon Nov 20 18:59:01 2023 +0100
Timestamp: 1700503141

Change depth - 1 to newDepth

Replacing 'depth - 1' with 'newDepth' in the singularbeta formula
utilizes existing variables more succinctly.

closes https://github.com/official-stockfish/Stockfish/pull/4876

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Stefan Geschwentner
Date: Thu Nov 16 09:10:20 2023 +0100
Timestamp: 1700122220

Fix undefined behavior in search.

We use following line to clamp the search depth in some range:
Depth d = std::clamp(newDepth - r, 1, newDepth + 1);

Through negative extension its possible that the maximum value becomes smaller than the minimum value but then the behavior is undefined (see https://en.cppreference.com/w/cpp/algorithm/clamp). So replace this line with a safe implementation.

Remark:
We have in recent master already one line where up to 3 negative extensions are possible which could trigger this undefined behavior but this can only be happen for completed depth > 24 so its not discovered by our default bench. Recent negative extension tests by @fauzi shows then this undefined behavior with wrong bench numbers.

closes https://github.com/official-stockfish/Stockfish/pull/4877

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Joost VandeVondele
Date: Thu Nov 16 09:01:57 2023 +0100
Timestamp: 1700121717

CI updates

- updates the SDE action to v2.2
- removes the linux x86-32 builds, which were almost unused,
and the build process under SDE started failing recently,
possibly related to glibc update (The futex facility returned an unexpected error code.)

closes https://github.com/official-stockfish/Stockfish/pull/4875

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Joost VandeVondele
Date: Wed Nov 15 19:35:14 2023 +0100
Timestamp: 1700073314

Symmetrize optimism

Removes some additional parameters, making the term more logical at the same
time.

Passed STC:
https://tests.stockfishchess.org/tests/view/6550e896136acbc5735328ed
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 271104 W: 68441 L: 68480 D: 134183 Elo -0.05
Ptnml(0-2): 827, 32590, 68816, 32433, 886

Passed LTC:
https://tests.stockfishchess.org/tests/view/65523858136acbc5735344f7
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 198954 W: 49250 L: 49211 D: 100493 Elo +0.07
Ptnml(0-2): 93, 22565, 54117, 22614, 88

closes https://github.com/official-stockfish/Stockfish/pull/4874

Bench: 1334248
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Taras Vuk
Date: Wed Nov 15 19:32:59 2023 +0100
Timestamp: 1700073179

Introduce recapture extensions

When in a PV-node this patch extends ttMove if it is a recapture and has a good
history.

Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 83840 W: 21560 L: 21166 D: 41114 Elo +1.63
Ptnml(0-2): 343, 9905, 21027, 10305, 340
https://tests.stockfishchess.org/tests/view/654f4b02136acbc5735308ab

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 165318 W: 41068 L: 40476 D: 83774 Elo +1.24
Ptnml(0-2): 98, 18670, 44517, 19290, 84
https://tests.stockfishchess.org/tests/view/654fde04136acbc5735314e0

closes https://github.com/official-stockfish/Stockfish/pull/4872

Bench: 1393911
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Linmiao Xu
Date: Sat Nov 11 15:26:56 2023 +0100
Timestamp: 1699712816

Simplify away optimism average score offset params

Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/654abf6b136acbc57352ac4b
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 49664 W: 12687 L: 12477 D: 24500 Elo +1.47
Ptnml(0-2): 138, 5840, 12703, 5976, 175

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/654b638e136acbc57352b961
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 347166 W: 85561 L: 85676 D: 175929 Elo -0.12
Ptnml(0-2): 206, 39569, 94150, 39450, 208

closes https://github.com/official-stockfish/Stockfish/pull/4871

bench 1257641
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Stefan Geschwentner
Date: Tue Nov 7 08:28:43 2023 +0100
Timestamp: 1699342123

Double weight of pawn history for quiet move ordering.

I measured on my 1000 position bench the average additional added pawn history per depth.
This shows on average negative value with even smaller values with increaing depth.

A linear regression against depth get following formula:

-1960 - 130 * depth

For compensation add this to the used sort limit to maintain roughly the same proportion of sorted quiet moves.

Remarks:
1. using no compensation failed here https://tests.stockfishchess.org/tests/view/6547664f136acbc5735265f0
2. using only the compensation failed at LTC:
passed STC: https://tests.stockfishchess.org/tests/view/65477457136acbc5735266f8
failed LTC: https://tests.stockfishchess.org/tests/view/65487fc8136acbc573527d1c

STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 98528 W: 25109 L: 24699 D: 48720 Elo +1.45
Ptnml(0-2): 334, 11586, 25009, 12006, 329
https://tests.stockfishchess.org/tests/view/65475873136acbc5735264f7

LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 69726 W: 17467 L: 17073 D: 35186 Elo +1.96
Ptnml(0-2): 39, 7814, 18769, 8196, 45
https://tests.stockfishchess.org/tests/view/6547e759136acbc573527071

closes https://github.com/official-stockfish/Stockfish/pull/4866

Bench: 1379422
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Taras Vuk
Date: Tue Nov 7 08:23:11 2023 +0100
Timestamp: 1699341791

Remove pawn history from ProbCut constructor

use same style as other history tables

Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 184672 W: 46953 L: 46896 D: 90823 Elo +0.11
Ptnml(0-2): 604, 21095, 48887, 21140, 610
https://tests.stockfishchess.org/tests/view/654766b4136acbc573526602

closes https://github.com/official-stockfish/Stockfish/pull/4865

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Taras Vuk
Date: Sun Nov 5 19:54:59 2023 +0100
Timestamp: 1699210499

Use stat_malus when decreasing stats

This patch applies stat_bonus when increasing and stat_malus when decreasing stats.

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 133792 W: 34221 L: 33758 D: 65813 Elo +1.20
Ptnml(0-2): 477, 15764, 33959, 16211, 485
https://tests.stockfishchess.org/tests/view/654699f3136acbc5735256b2

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 67374 W: 16912 L: 16523 D: 33939 Elo +2.01
Ptnml(0-2): 42, 7528, 18171, 7891, 55
https://tests.stockfishchess.org/tests/view/65474558136acbc5735263ab

closes https://github.com/official-stockfish/Stockfish/pull/4864

bench: 1114417
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Sun Nov 5 19:53:15 2023 +0100
Timestamp: 1699210395

Set reduction to 0 if the move is a TT move

The reduction formula currently decreases by 1 if the move is a TT move.
This changes this by just setting the reduction to 0 instead.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 83136 W: 21145 L: 20758 D: 41233 Elo +1.62
Ptnml(0-2): 279, 9772, 21090, 10137, 290
https://tests.stockfishchess.org/tests/view/653c0fbacc309ae839561584

Passed LTC:
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 273150 W: 67987 L: 67171 D: 137992 Elo +1.04
Ptnml(0-2): 155, 30730, 73966, 31592, 132
https://tests.stockfishchess.org/tests/view/653d9d02cc309ae839562fdf

closes https://github.com/official-stockfish/Stockfish/pull/4863

bench: 1110556
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Shahin M. Shahin
Date: Sun Nov 5 19:51:02 2023 +0100
Timestamp: 1699210262

Enhance some comments

This documents some code and makes some hard code easier to understand for new developers.

closes https://github.com/official-stockfish/Stockfish/pull/4862

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Sat Nov 4 17:34:35 2023 +0100
Timestamp: 1699115675

Tweaking the futility pruning formula

Huge credit goes also to candirufish,
as the idea was first tried by him, and then tuned by me at multiple phases.

Tweaking the futility pruning formula to be a bit more selective about when pruning is applied.
Adjust the value added to the static eval based on the bestValue relative to ss->staticEval. If bestValue is significantly lower, we add a larger value.

Passed STC:
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 37120 W: 9590 L: 9266 D: 18264 Elo +3.03
Ptnml(0-2): 130, 4301, 9385, 4603, 141
https://tests.stockfishchess.org/tests/view/6544cf90136acbc573523247

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 49632 W: 12381 L: 12033 D: 25218 Elo +2.44
Ptnml(0-2): 30, 5429, 13549, 5779, 29
https://tests.stockfishchess.org/tests/view/65453bc1136acbc573523a3c

closes https://github.com/official-stockfish/Stockfish/pull/4861

bench: 1107118
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Michael Chaly
Date: Fri Nov 3 22:50:05 2023 +0100
Timestamp: 1699048205

Update pawn history based on static eval difference

Use the same logic as in main history but with 1/4 multiplier.

Passed STC:
https://tests.stockfishchess.org/tests/view/653c1282cc309ae8395615bf
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 306624 W: 77811 L: 77094 D: 151719 Elo +0.81
Ptnml(0-2): 975, 36411, 77830, 37114, 982

Passed LTC:
https://tests.stockfishchess.org/tests/view/654258e2cc309ae83956818d
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 99150 W: 24681 L: 24228 D: 50241 Elo +1.59
Ptnml(0-2): 56, 11107, 26792, 11568, 52

closes https://github.com/official-stockfish/Stockfish/pull/4859

bench 1330590
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Stefan Geschwentner
Date: Fri Nov 3 22:47:31 2023 +0100
Timestamp: 1699048051

Remove razoring history update.

The recently commit 'Rewarding Quiet Moves that Enable Razoring' add a history update if razoring. But its contains also many tuned values all over the search. Following tests shows that the tuned values and not the added history update is responsible for the elo gain. So remove later.

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 29376 W: 7641 L: 7410 D: 14325 Elo +2.73
Ptnml(0-2): 100, 3411, 7451, 3610, 116
https://tests.stockfishchess.org/tests/view/653c9fe1cc309ae839562070

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 242922 W: 59879 L: 59885 D: 123158 Elo -0.01
Ptnml(0-2): 129, 27764, 65688, 27744, 136
https://tests.stockfishchess.org/tests/view/653d06cbcc309ae839562735

closes https://github.com/official-stockfish/Stockfish/pull/4858

Bench: 1286104
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Fri Nov 3 22:40:43 2023 +0100
Timestamp: 1699047643

Simplifying two formulas

by eliminating two multiplication operations.

Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 60000 W: 15193 L: 14996 D: 29811 Elo +1.14
Ptnml(0-2): 199, 7100, 15215, 7277, 209
https://tests.stockfishchess.org/tests/view/653beb69cc309ae83956129d

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 122910 W: 30471 L: 30353 D: 62086 Elo +0.33
Ptnml(0-2): 68, 13961, 33271, 14095, 60
https://tests.stockfishchess.org/tests/view/653c5848cc309ae839561ae7

closes https://github.com/official-stockfish/Stockfish/pull/4857

bench: 1216779
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: cj5716
Date: Fri Nov 3 22:39:04 2023 +0100
Timestamp: 1699047544

Prefetch TT entries in probcut

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 101344 W: 25893 L: 25491 D: 49960 Elo +1.38
Ptnml(0-2): 303, 11350, 26991, 11698, 330
https://tests.stockfishchess.org/tests/view/6540daa6cc309ae83956669b

slight speedup:
```
Result of 100 runs
==================
base (./stockfish.master ) = 1170705 +/- 3133
test (./stockfish.patch ) = 1174545 +/- 2895
diff = +3841 +/- 3196

speedup = +0.0033
P(speedup > 0) = 0.9907
```

closes https://github.com/official-stockfish/Stockfish/pull/4856

No functional change
see source

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