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: FauziAkram
Date: Mon Jun 3 23:12:13 2024 +0200
Timestamp: 1717449133

Simplify continuation histories

Functional simplification.

Simplify continuation histories, therefore increasing the effect of
stats updates and movepicker bonuses for continuation history 3 plies
deep.

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 229184 W: 59087 L: 59080 D: 111017 Elo +0.01
Ptnml(0-2): 554, 27248, 59002, 27213, 575
https://tests.stockfishchess.org/tests/view/665c7a09fd45fb0f907c223b

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 44532 W: 11419 L: 11223 D: 21890 Elo +1.53
Ptnml(0-2): 18, 4787, 12457, 4989, 15
https://tests.stockfishchess.org/tests/view/665c8842fd45fb0f907c23ec

closes https://github.com/official-stockfish/Stockfish/pull/5339

Bench: 1326444
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: Disservin
Date: Mon Jun 3 23:11:59 2024 +0200
Timestamp: 1717449119

Add helpers for managing aligned memory

Previously, we had two type aliases, LargePagePtr and AlignedPtr, which
required manually initializing the aligned memory for the pointer.

The new helpers:

- make_unique_aligned
- make_unique_large_page

are now available for allocating aligned memory (with large pages). They
behave similarly to std::make_unique, ensuring objects allocated with
these functions follow RAII.

The old approach had issues with initializing non-trivial types or
arrays of objects. The evaluation function of the network is now a
unique pointer to an array instead of an array of unique pointers.

Memory related functions have been moved into memory.h

Passed High Hash Pressure Test Non-Regression STC:
https://tests.stockfishchess.org/tests/view/665b2b36586058766677cfd2
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 476992 W: 122426 L: 122677 D: 231889 Elo -0.18
Ptnml(0-2): 1145, 51027, 134419, 50744, 1161

Failed Normal Non-Regression STC:
https://tests.stockfishchess.org/tests/view/665b2997586058766677cfc8
LLR: -2.94 (-2.94,2.94) <-1.75,0.25>
Total: 877312 W: 225233 L: 226395 D: 425684 Elo -0.46
Ptnml(0-2): 2110, 94642, 246239, 93630, 2035

Probably a fluke since there shouldn't be a real slowndown and it has also
passed the high hash pressure test.

closes https://github.com/official-stockfish/Stockfish/pull/5332

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: Mon Jun 3 08:54:24 2024 +0200
Timestamp: 1717397664

Fix GetProcessGroupAffinity call

`GetProcessGroupAffinity` appears to require 4 byte alignment for `GroupArray` memory.

See https://stackoverflow.com/q/78567676 for further information

closes https://github.com/official-stockfish/Stockfish/pull/5340

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: Sun Jun 2 09:23:28 2024 +0200
Timestamp: 1717313008

Revert "Adjust return bonus from tt cutoffs at fail highs"

This reverts commit 783dfc2eb235236ff799618436d68d0c1a3f3807.

could lead to a division by zero for:

ttValue = (ttValue * tte->depth() + beta) / (tte->depth() + 1)

as other threads can overwrite the tte with a QS depth of -1.

closes https://github.com/official-stockfish/Stockfish/pull/5338

Bench: 1280020
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 Jun 1 20:17:38 2024 +0200
Timestamp: 1717265858

Simplify statScore divisor into a constant

Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/665b392ff4a1fd0c208ea864
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 114752 W: 29628 L: 29495 D: 55629 Elo +0.40
Ptnml(0-2): 293, 13694, 29269, 13827, 293

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/665b588c11645bd3d3fac467
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 65322 W: 16549 L: 16373 D: 32400 Elo +0.94
Ptnml(0-2): 30, 7146, 18133, 7322, 30

closes https://github.com/official-stockfish/Stockfish/pull/5337

bench 1241443
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: xoto10
Date: Sat Jun 1 20:12:36 2024 +0200
Timestamp: 1717265556

Simplify tm, removing faster 1st move and 1.13 extraTime.

Passed STC 10+0.1 :
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 349760 W: 90112 L: 90231 D: 169417 Elo -0.12
Ptnml(0-2): 784, 37970, 97496, 37841, 789
https://tests.stockfishchess.org/tests/view/665aeee00223e235f05b7d21

Passed LTC 60+0.6 :
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 140082 W: 35463 L: 35370 D: 69249 Elo +0.23
Ptnml(0-2): 59, 13492, 42851, 13575, 64
https://tests.stockfishchess.org/tests/view/665b15e78da109e362924e5a

closes https://github.com/official-stockfish/Stockfish/pull/5334

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: Sat Jun 1 20:09:47 2024 +0200
Timestamp: 1717265387

Simplify 50 move rule dampening

Refactor the logic of 50 move rule dampening by removing a constant.

Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 35232 W: 9214 L: 8992 D: 17026 Elo +2.19
Ptnml(0-2): 114, 4081, 8999, 4313, 109
https://tests.stockfishchess.org/tests/view/665a329013d08af3c1725610

Passed non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 38406 W: 9732 L: 9530 D: 19144 Elo +1.83
Ptnml(0-2): 14, 4132, 10708, 4336, 13
https://tests.stockfishchess.org/tests/view/665a370913d08af3c1725651

https://github.com/official-stockfish/Stockfish/pull/5327

Bench: 1059739
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 Jun 1 20:08:08 2024 +0200
Timestamp: 1717265288

Simplify histories movepick formula

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 81440 W: 21100 L: 20929 D: 39411 Elo +0.73
Ptnml(0-2): 248, 9659, 20718, 9864, 231
https://tests.stockfishchess.org/tests/view/6659a8b7ea624d64ea5f3208

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 85758 W: 21763 L: 21607 D: 42388 Elo +0.63
Ptnml(0-2): 34, 9606, 23463, 9722, 54
https://tests.stockfishchess.org/tests/view/6659d7bff426908fcc6b692c

closes https://github.com/official-stockfish/Stockfish/pull/5326

bench: 1280472
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: Sat Jun 1 20:04:30 2024 +0200
Timestamp: 1717265070

Avoid changing bestvalue

in the case the ttValue contains mate scores, do not return them as bestValue, since they are not proven.

passed STC
https://tests.stockfishchess.org/tests/view/665b1ea5586058766677cfa3
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 58912 W: 15319 L: 15130 D: 28463 Elo +1.11
Ptnml(0-2): 141, 6562, 15854, 6765, 134

passed LTC:
https://tests.stockfishchess.org/tests/view/665b2712586058766677cfc4
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 141666 W: 35976 L: 35879 D: 69811 Elo +0.24
Ptnml(0-2): 61, 15513, 39584, 15618, 57

closes https://github.com/official-stockfish/Stockfish/pull/5335

Bench: 1336115
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: Sat Jun 1 20:02:09 2024 +0200
Timestamp: 1717264929

Adjust return bonus from tt cutoffs at fail highs

This is reintroduction of the recently simplified logic - if positive tt cutoff
occurs return not a tt value but smth between it and beta. Difference is that
instead of static linear combination there we use basically the same formula as
we do in the main search - with the only difference being using tt depth
instead of depth, which makes a lot of sense.

Passed STC:
https://tests.stockfishchess.org/tests/view/665b3a34f4a1fd0c208ea870
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 54944 W: 14239 L: 13896 D: 26809 Elo +2.17
Ptnml(0-2): 151, 6407, 14008, 6760, 146

Passed LTC:
https://tests.stockfishchess.org/tests/view/665b520011645bd3d3fac341
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 90540 W: 23070 L: 22640 D: 44830 Elo +1.65
Ptnml(0-2): 39, 9903, 24965, 10315, 48

closes https://github.com/official-stockfish/Stockfish/pull/5336

bench 1381237
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 Jun 1 19:59:07 2024 +0200
Timestamp: 1717264747

Update default smallnet to nn-37f18f62d772.nnue

Created by training L1-128 from scratch with:
- skipping based on simple eval in the trainer, for compatibility with
regular binpacks without requiring pre-filtering all binpacks
- minimum simple eval of 950, lower than 1000 previously
- usage of some hse-v1 binpacks with minimum simple eval 1000
- addition of hse-v6 binpacks with minimum simple eval 500
- permuting the FT with 10k positions from fishpack32.binpack
- torch.compile to speed up smallnet training

Training is significantly slower when using non-pre-filtered binpacks due to
the increased skipping required.

This net was reached at epoch 339.

```
experiment-name: 128--S1-hse-1k-T80-v6-unfilt-less-sf--se-gt950-no-wld-skip

training-dataset:
/data/:
- dfrc99-16tb7p.v2.min.binpack

/data/hse-v1/:
- leela96-filt-v2.min.high-simple-eval-1k.min-v2.binpack

- test60-novdec2021-12tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack

- test77-nov2021-2tb7p.no-db.min.high-simple-eval-1k.min-v2.binpack
- test77-dec2021-16tb7p.no-db.min.high-simple-eval-1k.min-v2.binpack
- test77-jan2022-2tb7p.high-simple-eval-1k.min-v2.binpack

- test78-jantomay2022-16tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack
- test78-juntosep2022-16tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack

- test79-apr2022-16tb7p.min.high-simple-eval-1k.min-v2.binpack
- test79-may2022-16tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack

- test80-apr2022-16tb7p.min.high-simple-eval-1k.min-v2.binpack
- test80-may2022-16tb7p.high-simple-eval-1k.min-v2.binpack
- test80-jun2022-16tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack
- test80-jul2022-16tb7p.v6-dd.min.high-simple-eval-1k.min-v2.binpack
- test80-sep2022-16tb7p-filter-v6-dd.min-mar2023.unmin.high-simple-eval-1k.min-v2.binpack
- test80-nov2022-16tb7p-v6-dd.min.high-simple-eval-1k.min-v2.binpack

/data/S11-mar2024/:
- test80-2022-08-aug-16tb7p.v6-dd.min.binpack
- test80-2022-10-oct-16tb7p.v6-dd.binpack
- test80-2022-12-dec-16tb7p.min.binpack

- test80-2023-01-jan-16tb7p.v6-sk20.min.binpack
- test80-2023-02-feb-16tb7p.v6-sk20.min.binpack
- test80-2023-03-mar-2tb7p.v6-sk16.min.binpack
- test80-2023-04-apr-2tb7p.v6-sk16.min.binpack
- test80-2023-05-may-2tb7p.v6.min.binpack
- test80-2023-06-jun-2tb7p.binpack.min-v2.binpack
- test80-2023-07-jul-2tb7p.binpack.min-v2.binpack
- test80-2023-08-aug-2tb7p.v6.min.binpack
- test80-2023-09-sep-2tb7p.binpack.hse-v6.binpack
- test80-2023-10-oct-2tb7p.binpack.hse-v6.binpack
- test80-2023-11-nov-2tb7p.binpack.hse-v6.binpack
- test80-2023-12-dec-2tb7p.binpack.hse-v6.binpack

- test80-2024-01-jan-2tb7p.binpack.hse-v6.binpack
- test80-2024-02-feb-2tb7p.binpack.hse-v6.binpack
- test80-2024-03-mar-2tb7p.binpack

wld-fen-skipping: False

nnue-pytorch-branch: linrock/nnue-pytorch/128-skipSimpleEval-lt950-torch-compile
engine-test-branch: linrock/Stockfish/L1-128-nolazy
engine-base-branch: linrock/Stockfish/L1-128
start-from-engine-test-net: False

num-epochs: 500
start-lambda: 1.0
end-lambda: 1.0
```

Training data can be found at:
https://robotmoon.com/nnue-training-data/

Passed STC:
https://tests.stockfishchess.org/tests/view/66549c16a86388d5e27daff5
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 196608 W: 51254 L: 50697 D: 94657 Elo +0.98
Ptnml(0-2): 722, 23244, 49796, 23839, 703

Passed LTC:
https://tests.stockfishchess.org/tests/view/6658d1aa6b0e318cefa90122
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 122538 W: 31332 L: 30835 D: 60371 Elo +1.41
Ptnml(0-2): 69, 13407, 33811, 13922, 60

closes https://github.com/official-stockfish/Stockfish/pull/5333

bench
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: rn5f107s2
Date: Sat Jun 1 19:58:20 2024 +0200
Timestamp: 1717264700

MCP more after a bad singular search

The idea is, that if we have the information that the singular search failed low and therefore produced an upperbound score, we can use the score from singularsearch as approximate upperbound as to what bestValue our non ttMoves will produce. If this value is well below alpha, we assume that all non-ttMoves will score below alpha and therfore can skip more moves.
This patch also sets up variables for future patches wanting to use teh singular search result outside of singular extensions, in singularBound and singularValue, meaning further patches using this search result to affect various pruning techniques can be tried.

Passed STC:
https://tests.stockfishchess.org/tests/view/6658d13e6b0e318cefa90120
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 85632 W: 22112 L: 21725 D: 41795 Elo +1.57
Ptnml(0-2): 243, 10010, 21947, 10349, 267

Passed LTC:
https://tests.stockfishchess.org/tests/view/6658dd356b0e318cefa9016a
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 243978 W: 62014 L: 61272 D: 120692 Elo +1.06
Ptnml(0-2): 128, 26598, 67791, 27348, 124

closes https://github.com/official-stockfish/Stockfish/pull/5325

bench 1397172
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 Jun 1 19:56:05 2024 +0200
Timestamp: 1717264565

Quadratic smallnet threshold with re-evaluation

The threshold now decreases more quickly as pawn count decreases,
using the smallnet more compared to before.

Combo of two eval patches:
https://tests.stockfishchess.org/tests/view/66576c5f6b0e318cefa8d26e
https://tests.stockfishchess.org/tests/view/664ced40830eb9f886616a77

Passed STC:
https://tests.stockfishchess.org/tests/view/66588c136b0e318cefa8ff21
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 112608 W: 29336 L: 28908 D: 54364 Elo +1.32
Ptnml(0-2): 344, 13223, 28718, 13699, 320

Passed LTC:
https://tests.stockfishchess.org/tests/view/6658c8786b0e318cefa900f5
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 108288 W: 27493 L: 27026 D: 53769 Elo +1.50
Ptnml(0-2): 54, 11821, 29930, 12282, 57

closes https://github.com/official-stockfish/Stockfish/pull/5323

bench 1728074
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 Jun 1 19:53:13 2024 +0200
Timestamp: 1717264393

Tweak first picked move (ttMove) reduction rule

Tweak first picked move (ttMove) reduction rule:

Instead of always resetting the reduction to 0, we now only do so if the current reduction is less than 2.
If the current reduction is 2 or more, we decrease it by 2 instead.

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 109504 W: 28340 L: 27919 D: 53245 Elo +1.34
Ptnml(0-2): 305, 12848, 28028, 13263, 308
https://tests.stockfishchess.org/tests/view/6658c2fa6b0e318cefa900c2

Passed LTC:
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 130410 W: 33248 L: 32738 D: 64424 Elo +1.36
Ptnml(0-2): 53, 14139, 36328, 14615, 70
https://tests.stockfishchess.org/tests/view/6658dd8a6b0e318cefa90173

closes https://github.com/official-stockfish/Stockfish/pull/5321

bench: 1224588
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 May 30 23:07:25 2024 +0200
Timestamp: 1717103245

Fix cross from Linux to Windows

specifies Windows 7 required

https://learn.microsoft.com/en-us/cpp/porting/modifying-winver-and-win32-winnt?view=msvc-170

closes https://github.com/official-stockfish/Stockfish/pull/5319

No functional change
see source
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: Thu May 30 23:05:25 2024 +0200
Timestamp: 1717103125

On linux use sysfs instead of lscpu

Use sysfs (https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-devices-node)
to determine processor to NUMA node mapping.

Avoids problems on some machines with high core count where lscpu was showing high cpu utilization.

closes https://github.com/official-stockfish/Stockfish/pull/5315

No functional change
see source
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: Thu May 30 23:05:21 2024 +0200
Timestamp: 1717103121

Replace std::from_chars with std::stoull

the former was not widely supported, requiring newer compiler versions.

closes https://github.com/official-stockfish/Stockfish/pull/5313

No functional change
see source
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: Thu May 30 23:05:16 2024 +0200
Timestamp: 1717103116

Fix process' processor affinity determination on Windows.

Specialize and privatize NumaConfig::get_process_affinity.
Only enable NUMA capability for 64-bit Windows.

Following #5307 and some more testing it was determined that the way affinity
was being determined on Windows was incorrect, based on incorrect assumptions
about GetNumaProcessorNodeEx.

This patch fixes the issue by attempting to retrieve the actual process'
processor affinity using Windows API. However one issue persists that is not
addressable due to limitations of Windows, and will have to be considered a
limitation. If affinities were set using SetThreadAffinityMask instead of
SetThreadSelectedCpuSetMasks and GetProcessGroupAffinity returns more than 1
group it is NOT POSSIBLE to determine the affinity programmatically on Windows.
In such case the implementation assumes no affinites are set and will consider
all processors available for execution.

closes https://github.com/official-stockfish/Stockfish/pull/5312

No functional change
see source
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Disservin
Date: Thu May 30 23:05:01 2024 +0200
Timestamp: 1717103101

NUMA: Fix concurrency counting for windows systems

If there is more than 1 processor group, std::thread::hardware_concurrency should not be used.

fixes #5307

closes https://github.com/official-stockfish/Stockfish/pull/5311

No functional change
see source
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Thu May 30 23:00:22 2024 +0200
Timestamp: 1717102822

Simplifying the malus for putting piece en prise formula

Simplifying the malus for putting piece en prise
formula by merging the minor pieces and pawns
(removing the pawn exclusion from the formula).

Passed STC:
https://tests.stockfishchess.org/tests/view/66578d9c6b0e318cefa8d441
LLR: 2.99 (-2.94,2.94) <-1.75,0.25>
Total: 314272 W: 80705 L: 80786 D: 152781 Elo -0.09
Ptnml(0-2): 873, 37577, 80366, 37398, 922

Passed LTC (before rebasing):
https://tests.stockfishchess.org/tests/view/6657b5ee6b0e318cefa8d6ab
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 117000 W: 29447 L: 29324 D: 58229 Elo +0.37
Ptnml(0-2): 47, 12877, 32535, 12988, 53

Passed LTC (also after rebasing):
https://tests.stockfishchess.org/tests/view/6658803d6b0e318cefa8fd99
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 244992 W: 61807 L: 61814 D: 121371 Elo -0.01
Ptnml(0-2): 125, 27420, 67414, 27411, 126

closes https://github.com/official-stockfish/Stockfish/pull/5316

Bench: 1484840
see source
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: Thu May 30 22:54:23 2024 +0200
Timestamp: 1717102463

Allow tt cutoffs for shallower depths in certain conditions

Current master allows tt cutoffs only when depth
from tt is strictly greater than current node
depth. This patch also allows them when it's equal
and if tt value is lower or equal to beta.

Passed STC:
https://tests.stockfishchess.org/tests/view/66578e2e6b0e318cefa8d447
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 26592 W: 6944 L: 6645 D: 13003 Elo +3.91
Ptnml(0-2): 67, 3039, 6795, 3318, 77

Passed LTC:
https://tests.stockfishchess.org/tests/view/6657f46b6b0e318cefa8d7e9
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 142572 W: 36315 L: 35776 D: 70481 Elo +1.31
Ptnml(0-2): 70, 15666, 39288, 16179, 83

closes https://github.com/official-stockfish/Stockfish/pull/5314

Bench: 1368486
see source
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: FauziAkram
Date: Thu May 30 22:53:20 2024 +0200
Timestamp: 1717102400

Functional simplification in the transposition table

Passed STC:
LLR: 2.98 (-2.94,2.94) <-1.75,0.25>
Total: 154848 W: 39838 L: 39750 D: 75260 Elo +0.20
Ptnml(0-2): 404, 16214, 44087, 16328, 391
https://tests.stockfishchess.org/tests/view/664892b088b8c6a2bbe430fc

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 68172 W: 17296 L: 17137 D: 33739 Elo +0.81
Ptnml(0-2): 23, 6349, 21185, 6504, 25
https://tests.stockfishchess.org/tests/view/6648aabfa0781149e383e526

closes https://github.com/official-stockfish/Stockfish/pull/5263

Bench: 1623228
see source
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Viren6
Date: Thu May 30 14:34:24 2024 +0200
Timestamp: 1717072464

Add extension condition to cutoffCnt

Decrease cutoffCnt increment by 1 if extension is 2 or greater.

Passed STC:
https://tests.stockfishchess.org/tests/view/66577a696b0e318cefa8d34d
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 99200 W: 25703 L: 25297 D: 48200 Elo +1.42
Ptnml(0-2): 253, 11660, 25390, 12022, 275

Passed LTC:
https://tests.stockfishchess.org/tests/view/665787ab6b0e318cefa8d411
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 124530 W: 31659 L: 31161 D: 61710 Elo +1.39
Ptnml(0-2): 58, 13578, 34489, 14088, 52

closes https://github.com/official-stockfish/Stockfish/pull/5310

bench 1623228
see source
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: Thu May 30 14:29:31 2024 +0200
Timestamp: 1717072171

Tweak and update the WDL model

This PR updates the internal WDL model, using data from 2.5M games played by SF-dev (3c62ad7).
Note that the normalizing constant has increased from 329 to 368.

Changes to the fitting procedure:

* the value for --materialMin was increased from 10 to 17: including data with less material leads to less accuracy for larger material count values
* the data was filtered to only include single thread LTC games at 60+0.6
* the data was filtered to only include games from master against patches that are (approximatively) within 5 nElo of master

For more information and plots of the model see PR#5309

closes https://github.com/official-stockfish/Stockfish/pull/5309

No functional change
see source
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: Thu May 30 14:28:07 2024 +0200
Timestamp: 1717072087

Update default main net to nn-ddcfb9224cdb.nnue

Created by further tuning the spsa-tuned main net `nn-c721dfca8cd3.nnue`
with the same methods described in https://github.com/official-stockfish/Stockfish/pull/5254

This net was reached at 61k / 120k spsa games at 70+0.7 th 7:
https://tests.stockfishchess.org/tests/view/665639d0a86388d5e27dd259

Passed STC:
https://tests.stockfishchess.org/tests/view/6657d44e6b0e318cefa8d771
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 114688 W: 29775 L: 29344 D: 55569 Elo +1.31
Ptnml(0-2): 274, 13633, 29149, 13964, 324

Passed LTC:
https://tests.stockfishchess.org/tests/view/6657e1e46b0e318cefa8d7a6
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 88152 W: 22412 L: 21988 D: 43752 Elo +1.67
Ptnml(0-2): 56, 9560, 24409, 10006, 45

closes https://github.com/official-stockfish/Stockfish/pull/5308

Bench: 1434678
see source

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