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 modern computers + AVX2
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: Shawn Xu
Date: Tue Sep 17 20:50:30 2024 +0200
Timestamp: 1726599030

Simplify Fail Low Bonus

Passed Non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 302528 W: 78190 L: 78264 D: 146074 Elo -0.08
Ptnml(0-2): 1029, 35797, 77551, 35993, 894
https://tests.stockfishchess.org/tests/view/66dcebdedc53972b68218c7e

Passed Non-regression LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 122754 W: 31025 L: 30907 D: 60822 Elo +0.33
Ptnml(0-2): 74, 13597, 33908, 13733, 65
https://tests.stockfishchess.org/tests/view/66e0c38686d5ee47d953a481

closes https://github.com/official-stockfish/Stockfish/pull/5594

Bench: 1646373
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
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: Tue Sep 17 20:47:24 2024 +0200
Timestamp: 1726598844

VVLTC Search Tune

Tuned with 115k games at VVLTC:
https://tests.stockfishchess.org/tests/view/66c80e09bf8c9d8780fda62a

Passed VVLTC 1st sprt:
https://tests.stockfishchess.org/tests/view/66d69ade9de3e7f9b33d14f9
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 54270 W: 13935 L: 13647 D: 26688 Elo +1.84
Ptnml(0-2): 2, 4907, 17032, 5189, 5

Passed VVLTC 2nd sprt:
https://tests.stockfishchess.org/tests/view/66dcf9c1dc53972b68218c84
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 136696 W: 34941 L: 34462 D: 67293 Elo +1.22
Ptnml(0-2): 8, 12659, 42535, 13138, 8

closes https://github.com/official-stockfish/Stockfish/pull/5592

Bench: 1644273
see source
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Disservin
Date: Tue Sep 17 20:24:17 2024 +0200
Timestamp: 1726597457

Port instrumented testing to python

Since an unknown amount of time the instrumented CI has been a bit
flawed, explained here
https://github.com/official-stockfish/Stockfish/issues/5185. It also
experiences random timeout issues where restarting the workflow fixes it
or very long run times (more than other workflows) and is not very
portable.

The intention of this commit is to port the instrumented.sh to python
which also works on other operating systems. It should also be
relatively easy for beginners to add new tests to assert stockfish's
output and to run it.
From the source directory the following command can be run.

`python3 ../tests/instrumented.py --none ./stockfish`

A test runner will go over the test suites and run the test cases.

All instrumented tests should have been ported over.
The required python version for this is should be 3.7 (untested) + the
requests package, testing.py includes some infrastructure code which
setups the testing.

fixes https://github.com/official-stockfish/Stockfish/issues/5185
closes https://github.com/official-stockfish/Stockfish/pull/5583

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: MinetaS
Date: Tue Sep 10 23:00:41 2024 +0200
Timestamp: 1726002041

Fix net downloading script

The recent commit introduced a bug in the net downloading script that
the file is not downloaded correctly and the content is redirected to
stdout.

closes https://github.com/official-stockfish/Stockfish/pull/5585

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
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: Nonlinear2
Date: Tue Sep 10 22:59:27 2024 +0200
Timestamp: 1726001967

Remove the `moveCount` increase in the LMR condition.

Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 87104 W: 22630 L: 22464 D: 42010 Elo +0.66
Ptnml(0-2): 316, 10295, 22132, 10525, 284
https://tests.stockfishchess.org/tests/view/66dccd00dc53972b68218c60

Passed non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 94050 W: 23869 L: 23722 D: 46459 Elo +0.54
Ptnml(0-2): 49, 10400, 25985, 10537, 54
https://tests.stockfishchess.org/tests/view/66dd69c7dc53972b68218ca5

closes https://github.com/official-stockfish/Stockfish/pull/5582

Bench: 1281840
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: MinetaS
Date: Tue Sep 10 22:58:47 2024 +0200
Timestamp: 1726001927

Remove statScore condition in NMP

Eliminate the condition that is nearly 100% likelihood of being true.

Passed non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 208832 W: 54053 L: 54022 D: 100757 Elo +0.05
Ptnml(0-2): 753, 24987, 52901, 25026, 749
https://tests.stockfishchess.org/tests/view/66cddb50bf8c9d8780fdabaf

Passed non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 154344 W: 39132 L: 39047 D: 76165 Elo +0.19
Ptnml(0-2): 115, 17231, 42403, 17300, 123
https://tests.stockfishchess.org/tests/view/66cfafe39de3e7f9b33d1050

closes https://github.com/official-stockfish/Stockfish/pull/5558

Bench: 1393697
see source
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: MinetaS
Date: Mon Sep 9 18:02:32 2024 +0200
Timestamp: 1725897752

Small speedup in incremental accumulator updates

Instead of updating at most two accumulators, update all accumluators
during incremental updates. Tests have shown that this change yields a
small speedup of at least 0.5%, and up to 1% with shorter TC.

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 54368 W: 14179 L: 13842 D: 26347 Elo +2.15
Ptnml(0-2): 173, 6122, 14262, 6449, 178
https://tests.stockfishchess.org/tests/view/66db038a9de3e7f9b33d1ad9

Passed 5+0.05:
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 55040 W: 14682 L: 14322 D: 26036 Elo +2.27
Ptnml(0-2): 303, 6364, 13856, 6664, 333
https://tests.stockfishchess.org/tests/view/66dbc325dc53972b68218ba7

Passed non-regression LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 57390 W: 14555 L: 14376 D: 28459 Elo +1.08
Ptnml(0-2): 37, 5876, 16683, 6069, 30
https://tests.stockfishchess.org/tests/view/66dbc30adc53972b68218ba5

closes https://github.com/official-stockfish/Stockfish/pull/5576

No functional change
see source
Windows x64 for Haswell CPUs
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: Disservin
Date: Mon Sep 9 18:02:32 2024 +0200
Timestamp: 1725897752

Use optional for the engine path

- A small quality of file change is to change the type of engine path
from a string to an optional string, skips the binary directory
lookup, which is commonly disabled by people who create wasm builds or
include stockfish as a library.

closes https://github.com/official-stockfish/Stockfish/pull/5575

No functional change
see source
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: Mon Sep 9 18:02:32 2024 +0200
Timestamp: 1725897752

Simplify ttmove reduction

Remove condition that clamps reductions for tt move.

Passed STC:
https://tests.stockfishchess.org/tests/view/66d5f1239de3e7f9b33d14b0
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 91136 W: 23805 L: 23646 D: 43685 Elo +0.61
Ptnml(0-2): 334, 10328, 24066, 10525, 315

Passed LTC:
https://tests.stockfishchess.org/tests/view/66d7c5889de3e7f9b33d1721
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 139242 W: 35130 L: 35030 D: 69082 Elo +0.25
Ptnml(0-2): 78, 15200, 38986, 15258, 99

closes https://github.com/official-stockfish/Stockfish/pull/5574

Bench: 1268715
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
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: xu-shawn
Date: Mon Sep 9 18:02:32 2024 +0200
Timestamp: 1725897752

Remove ARCH=... from README.md

closes https://github.com/official-stockfish/Stockfish/pull/5570

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
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: MinetaS
Date: Mon Sep 9 18:02:27 2024 +0200
Timestamp: 1725897747

Export and clean up net downloading script

Fixes https://github.com/official-stockfish/Stockfish/issues/5564

This patch extracts the net downloading script in Makefile into an
external script file. Also the script is moderately rewritten for
improved readability and speed.

* Use wget preferentially over curl, as curl is known to have slight
overhead.
* Use command instead of hash to check if command exists. Reportedly,
hash always returns zero in some POSIX shells even when the command
fails.
* Command existence checks (wget/curl, sha256sum) are performed only
once at the beginning.
* Each of common patterns is encapsulated in a function
(get_nnue_filename, validate_network).
* Print out error/warning messages to stderr.

closes https://github.com/official-stockfish/Stockfish/pull/5563

No functional change

Co-authored-by: Disservin <>
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: xu-shawn
Date: Mon Sep 9 17:54:27 2024 +0200
Timestamp: 1725897267

Copy scripts directory in distributed packages

closes https://github.com/official-stockfish/Stockfish/pull/5571

No functional change
see source
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: Daniel Monroe
Date: Mon Sep 9 17:48:26 2024 +0200
Timestamp: 1725896906

Reduce on ttcaptures if not capture

Tweak ttcapture reduction.
Reduce on ttcaptures only if the current move is a capture

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 94912 W: 24896 L: 24492 D: 45524 Elo +1.48
Ptnml(0-2): 301, 11197, 24087, 11539, 332
https://tests.stockfishchess.org/tests/view/66cd2264bf8c9d8780fdab34

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 60738 W: 15465 L: 15096 D: 30177 Elo +2.11
Ptnml(0-2): 42, 6573, 16775, 6932, 47
https://tests.stockfishchess.org/tests/view/66cf356d9de3e7f9b33d0fde

closes https://github.com/official-stockfish/Stockfish/pull/5562

Bench: 1268700
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: Shawn Xu
Date: Mon Sep 9 17:43:05 2024 +0200
Timestamp: 1725896585

Introduce Material Correction History

Idea from Caissa (https://github.com/Witek902/Caissa) chess engine.

Add a secondary correction history indexed by the material key of a position.
The material key is the zobrist hash representing the number of pieces left in a
position.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 189472 W: 49360 L: 48813 D: 91299 Elo +1.00
Ptnml(0-2): 666, 22453, 47953, 22996, 668
https://tests.stockfishchess.org/tests/view/66cbddafbf8c9d8780fda9f1

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 224190 W: 57022 L: 56312 D: 110856 Elo +1.10
Ptnml(0-2): 197, 24723, 61540, 25443, 192
https://tests.stockfishchess.org/tests/view/66cd529bbf8c9d8780fdab4c

closes https://github.com/official-stockfish/Stockfish/pull/5556

Bench: 1462697
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 Sep 9 17:34:31 2024 +0200
Timestamp: 1725896071

Simplify history bonus

After we recently added the disallowance for negative bonuses, it is no
longer necessary to keep the max comparison in the previous step.

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 72000 W: 18820 L: 18637 D: 34543 Elo +0.88
Ptnml(0-2): 267, 8489, 18276, 8730, 238
https://tests.stockfishchess.org/tests/view/66ce132cbf8c9d8780fdabe7

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 67452 W: 17136 L: 16961 D: 33355 Elo +0.90
Ptnml(0-2): 35, 7489, 18519, 7632, 51
https://tests.stockfishchess.org/tests/view/66cf6ad49de3e7f9b33d1010

closes https://github.com/official-stockfish/Stockfish/pull/5554

Bench: 1147012
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Disservin
Date: Mon Sep 9 17:21:14 2024 +0200
Timestamp: 1725895274

Restore development

closes https://github.com/official-stockfish/Stockfish/pull/5580

No functional change
see source
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: Fri Sep 6 16:53:45 2024 +0200
Timestamp: 1725634425

Stockfish 17

Official release version of Stockfish 17

Bench: 1484730

---

Stockfish 17

Today we have the pleasure to announce a new major release of Stockfish. As
always, you can freely download it at https://stockfishchess.org/download and
use it in the GUI of your choice.

Don’t forget to join our Discord server[1] to get in touch with the community
of developers and users of the project!

*Quality of chess play*

In tests against Stockfish 16, this release brings an Elo gain of up to 46
points[2] and wins up to 4.5 times more game pairs[3] than it loses. In
practice, high-quality moves are now found in less time, with a user upgrading
from Stockfish 14 being able to analyze games at least 6 times[4] faster with
Stockfish 17 while maintaining roughly the same quality.

During this development period, Stockfish won its 9th consecutive first place
in the main league of the Top Chess Engine Championship (TCEC)[5], and the 24th
consecutive first place in the main events (bullet, blitz, and rapid) of the
Computer Chess Championship (CCC)[6].

*Update highlights*

*Improved engine lines*

This release introduces principal variations (PVs) that are more informative
for mate and decisive table base (TB) scores. In both cases, the PV will
contain all moves up to checkmate. For mate scores, the PV shown is the best
variation known to the engine at that point, while for table base wins, it
follows, based on the TB, a sequence of moves that preserves the game outcome
to checkmate.

*NUMA performance optimization*

For high-end computers with multiple CPUs (typically a dual-socket architecture
with 100+ cores), this release automatically improves performance with a
`NumaPolicy` setting that optimizes non-uniform memory access (NUMA). Although
typical consumer hardware will not benefit, speedups of up to 2.8x[7] have been
measured.

*Shoutouts*

*ChessDB*

During the past 1.5 years, hundreds of cores have been continuously running
Stockfish to grow a database of analyzed positions. This chess cloud
database[8] now contains well over 45 billion positions, providing excellent
coverage of all openings and commonly played lines. This database is already
integrated into GUIs such as En Croissant[9] and Nibbler[10], which access it
through the public API.

*Leela Chess Zero*

Generally considered to be the strongest GPU engine, it continues to provide
open data which is essential for training our NNUE networks. They released
version 0.31.1[11] of their engine a few weeks ago, check it out!

*Website redesign*

Our website has undergone a redesign in recent months, most notably in our home
page[12], now featuring a darker color scheme and a more modern aesthetic,
while still maintaining its core identity. We hope you'll like it as much as we
do!

*Thank you*

The Stockfish project builds on a thriving community of enthusiasts (thanks
everybody!) who contribute their expertise, time, and resources to build a free
and open-source chess engine that is robust, widely available, and very strong.

We would like to express our gratitude for the 11k stars[13] that light up our
GitHub project! Thank you for your support and encouragement – your recognition
means a lot to us.

We invite our chess fans to join the Fishtest testing framework[14] to
contribute compute resources needed for development. Programmers can contribute
to the project either directly to Stockfish[15] (C++), to Fishtest[16] (HTML,
CSS, JavaScript, and Python), to our trainer nnue-pytorch[17] (C++ and Python),
or to our website[18] (HTML, CSS/SCSS, and JavaScript).

The Stockfish team

[1] https://discord.gg/GWDRS3kU6R
[2] https://tests.stockfishchess.org/tests/view/66d738ba9de3e7f9b33d159a
[3] https://tests.stockfishchess.org/tests/view/66d738f39de3e7f9b33d15a0
[4] https://github.com/official-stockfish/Stockfish/wiki/Useful-data#equivalent-time-odds-and-normalized-game-pair-elo
[5] https://en.wikipedia.org/wiki/Stockfish_(chess)#Top_Chess_Engine_Championship
[6] https://en.wikipedia.org/wiki/Stockfish_(chess)#Chess.com_Computer_Chess_Championship
[7] https://github.com/official-stockfish/Stockfish/pull/5285
[8] https://chessdb.cn/queryc_en/
[9] https://encroissant.org/
[10] https://github.com/rooklift/nibbler
[11] https://github.com/LeelaChessZero/lc0/releases/tag/v0.31.1
[12] https://stockfishchess.org/
[13] https://github.com/official-stockfish/Stockfish/stargazers
[14] https://github.com/official-stockfish/fishtest/wiki/Running-the-worker
[15] https://github.com/official-stockfish/Stockfish
[16] https://github.com/official-stockfish/fishtest
[17] https://github.com/official-stockfish/nnue-pytorch
[18] https://github.com/official-stockfish/stockfish-web
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: Tue Sep 3 17:53:23 2024 +0200
Timestamp: 1725378803

Update Top CPU Contributors

to the status as of Aug 31st 2024.

closes https://github.com/official-stockfish/Stockfish/pull/5561

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Robert Nurnberg @ elitebook
Date: Tue Sep 3 17:53:23 2024 +0200
Timestamp: 1725378803

Update the WDL model

updates the internal WDL model, using data from 2.6M games played by the revisions since 9fb5832.

https://github.com/official-stockfish/Stockfish/pull/5565

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: Tue Sep 3 17:48:58 2024 +0200
Timestamp: 1725378538

Fix some of the tests

due to https://github.com/official-stockfish/Stockfish/issues/5185 some CI tests are skipped.
This patch fixes a few tests that need updating.

closes https://github.com/official-stockfish/Stockfish/pull/5560

No functional change
see source
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Wed Aug 28 09:35:21 2024 +0200
Timestamp: 1724830521

Simpler formula for ss->cutoffCnt update

closes https://github.com/official-stockfish/Stockfish/pull/5548

No functional change
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
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 Aug 28 09:34:09 2024 +0200
Timestamp: 1724830449

rename !(PvNode || cutNode) to allNode

Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 108992 W: 28178 L: 28039 D: 52775 Elo +0.44
Ptnml(0-2): 356, 12428, 28762, 12621, 329
https://tests.stockfishchess.org/tests/view/66c73a51bf8c9d8780fda532

closes https://github.com/official-stockfish/Stockfish/pull/5549

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: Tomasz Sobczyk
Date: Wed Aug 28 08:52:24 2024 +0200
Timestamp: 1724827944

Forcibly split NUMA nodes on Windows

split by processor groups due to Window's thread scheduler issues.

fixes #5551
closes https://github.com/official-stockfish/Stockfish/pull/5552

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: Tue Aug 20 21:37:25 2024 +0200
Timestamp: 1724182645

Tweak late move extensions

Allow late move extensions only for PV and cut nodes.

Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 44512 W: 11688 L: 11355 D: 21469 Elo +2.60
Ptnml(0-2): 167, 5180, 11229, 5513, 167
https://tests.stockfishchess.org/tests/view/66c0509d4ff211be9d4ef10e

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 152970 W: 39026 L: 38466 D: 75478 Elo +1.27
Ptnml(0-2): 102, 16792, 42164, 17298, 129
https://tests.stockfishchess.org/tests/view/66c0994d21503a509c13b2b6

closes https://github.com/official-stockfish/Stockfish/pull/5541

bench: 1484730
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Shawn Xu
Date: Tue Aug 20 21:34:19 2024 +0200
Timestamp: 1724182459

Introduce Fail Low History Bonus

When a node fails low, give TT move a small bonus 1/4 of normal value.

Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 92384 W: 24094 L: 23691 D: 44599 Elo +1.52
Ptnml(0-2): 323, 10852, 23465, 11203, 349
https://tests.stockfishchess.org/tests/view/66be80794ff211be9d4eed68

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 114660 W: 29260 L: 28778 D: 56622 Elo +1.46
Ptnml(0-2): 97, 12506, 31653, 12966, 108
https://tests.stockfishchess.org/tests/view/66bf63ee4ff211be9d4eeef0

closes https://github.com/official-stockfish/Stockfish/pull/5539

bench 1463003
see source

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