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
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: mstembera
Date: Thu Feb 27 20:30:10 2025 +0100
Timestamp: 1740684610

Handle updating the small accumulator the same way as the big one

https://tests.stockfishchess.org/tests/view/67abfe1ca04df5eb8dbebf0b
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 153088 W: 40072 L: 39979 D: 73037 Elo +0.21
Ptnml(0-2): 619, 16728, 41764, 16807, 626

closes https://github.com/official-stockfish/Stockfish/pull/5901

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 Feb 24 19:16:26 2025 +0100
Timestamp: 1740420986

Simplify bestvalue update formula

Passed STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 124960 W: 32598 L: 32472 D: 59890 Elo +0.35
Ptnml(0-2): 480, 14852, 31694, 14970, 484
https://tests.stockfishchess.org/tests/view/67b348bae00eea114cdba37d

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 150306 W: 38220 L: 38132 D: 73954 Elo +0.20
Ptnml(0-2): 98, 16430, 42005, 16526, 94
https://tests.stockfishchess.org/tests/view/67b5e37918a66624a7a3f751

closes https://github.com/official-stockfish/Stockfish/pull/5898

Bench: 2146010
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: Joost VandeVondele
Date: Mon Feb 24 19:15:32 2025 +0100
Timestamp: 1740420932

Check maximum time every iteration

This fixes a TCEC timeloss, where slow DTZ TB7 access, in combination
with syzygy PV extension, led to a timeloss.

While the extension code correctly aborted after spending moveOverhead/2
time, the mainThread did not search sufficient nodes (512 in > 1s) to
trigger the stop in check_time. At the same time, totalTime exceeded
tm.maximum() due to the factors multiplying tm.optimum().

This corner case is fixed by checking also against the tm.maximum() at
each iteration.

Even though this problem can't be triggered on fishtest, the patch was
verified there.

Passed STC:
https://tests.stockfishchess.org/tests/view/67b99e1be99f8640b318810d
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 136832 W: 35625 L: 35518 D: 65689 Elo +0.27
Ptnml(0-2): 499, 14963, 37431, 14978, 545

closes https://github.com/official-stockfish/Stockfish/pull/5896

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: Michael Chaly
Date: Mon Feb 24 19:14:04 2025 +0100
Timestamp: 1740420844

Make Pv search shallower in some cases

Conditions are the same as they are for doShallowerSearch, just that
they also apply for cases where LMR wasn't reducing anything - if result
is bad enough reduce search depth of PV search by 1.

Passed STC:
https://tests.stockfishchess.org/tests/view/67b9d2aca49c651c2caac818
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 29216 W: 7731 L: 7424 D: 14061 Elo +3.65
Ptnml(0-2): 87, 3345, 7473, 3580, 123

Passed LTC:
https://tests.stockfishchess.org/tests/view/67ba538c01f3463ae1d35e69
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 33168 W: 8529 L: 8219 D: 16420 Elo +3.25
Ptnml(0-2): 12, 3505, 9262, 3771, 34

closes https://github.com/official-stockfish/Stockfish/pull/5895

Bench: 2290732
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: Myself
Date: Mon Feb 24 19:12:35 2025 +0100
Timestamp: 1740420755

Add risk tolerance calculation

https://tests.stockfishchess.org/tests/view/67b1db2188b11e2400eb06ae
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 123552 W: 32388 L: 31938 D: 59226 Elo +1.27
Ptnml(0-2): 487, 14520, 31345, 14904, 520

Passed LTC:
https://tests.stockfishchess.org/tests/view/67b3d53f154c4df4fc4b1f43
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 206928 W: 52916 L: 52246 D: 101766 Elo +1.12
Ptnml(0-2): 159, 22546, 57394, 23196, 169

closes https://github.com/official-stockfish/Stockfish/pull/5893

Bench: 2705449
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: Disservin
Date: Mon Feb 24 19:10:38 2025 +0100
Timestamp: 1740420638

Remove duplicated info string printing

Currently "info string" is being printed twice for the network arch

```
info string info string NNUE evaluation using nn-1c0000000000.nnue (133MiB, (22528, 3072, 15, 32, 1))
info string info string NNUE evaluation using nn-37f18f62d772.nnue (6MiB, (22528, 128, 15, 32, 1))
```

closes https://github.com/official-stockfish/Stockfish/pull/5889

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: Shawn Xu
Date: Mon Feb 24 19:09:52 2025 +0100
Timestamp: 1740420592

Add scaling note to futility pruning

Note that both patches below effectively reduces the frequency of futility pruning.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 51680 W: 13599 L: 13253 D: 24828 Elo +2.33
Ptnml(0-2): 217, 6056, 12959, 6380, 228
https://tests.stockfishchess.org/tests/view/67ac218fa04df5eb8dbebf26

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 51798 W: 13338 L: 12986 D: 25474 Elo +2.36
Ptnml(0-2): 42, 5584, 14310, 5906, 57
https://tests.stockfishchess.org/tests/view/67acf04152879dfd14d7e846

Regression at STC SMP:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 231552 W: 60226 L: 59642 D: 111684 Elo +0.88
Ptnml(0-2): 565, 25994, 62031, 26664, 522
https://tests.stockfishchess.org/tests/view/67ae390c1a4c73ae1f930dbf

Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 22560 W: 6022 L: 5725 D: 10813 Elo +4.57
Ptnml(0-2): 87, 2524, 5762, 2819, 88
https://tests.stockfishchess.org/tests/view/67ac202aa04df5eb8dbebf22

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 66138 W: 16953 L: 16572 D: 32613 Elo +2.00
Ptnml(0-2): 62, 7103, 18360, 7480, 64
https://tests.stockfishchess.org/tests/view/67ad47d852879dfd14d7e899

Regression at VVLTC SMP:
LLR: -2.94 (-2.94,2.94) <-1.75,0.25>
Total: 29138 W: 7408 L: 7655 D: 14075 Elo -2.95
Ptnml(0-2): 0, 2816, 9189, 2559, 5
https://tests.stockfishchess.org/tests/view/67b159ce6c6b9e172ad1598f

closes https://github.com/official-stockfish/Stockfish/pull/5888

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: Nonlinear2
Date: Mon Feb 24 19:09:28 2025 +0100
Timestamp: 1740420568

se separate parameters for stat values

The code has been refactored to remove the `stat_bonus` and `stat_malus`
functions, as the code for each bonus/malus is now different. This
allows for future tests to modify these formulas individually.

Passed LTC with STC bounds:
https://tests.stockfishchess.org/tests/view/67b115dd6c6b9e172ad1592f
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 75756 W: 19393 L: 19044 D: 37319 Elo +1.60
Ptnml(0-2): 60, 8251, 20913, 8588, 66

Passed LTC with LTC bounds:
https://tests.stockfishchess.org/tests/view/67af5f5d6c6b9e172ad15765
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 108126 W: 27880 L: 27412 D: 52834 Elo +1.50
Ptnml(0-2): 85, 11786, 29866, 12228, 98

closes https://github.com/official-stockfish/Stockfish/pull/5887

Bench: 2809143
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: Daniel Monroe
Date: Mon Feb 24 19:07:58 2025 +0100
Timestamp: 1740420478

Use same term for small and large net for nnue complexity adjustment

Passed simplification STC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 386496 W: 100682 L: 100850 D: 184964 Elo -0.15
Ptnml(0-2): 1686, 46399, 97218, 46287, 1658
https://tests.stockfishchess.org/tests/view/67a9cc6d851bb0f25324449e

Passed rebased simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 160884 W: 41090 L: 41012 D: 78782 Elo +0.17
Ptnml(0-2): 133, 17883, 44321, 17983, 122
https://tests.stockfishchess.org/tests/view/67aef2e91a4c73ae1f930e85

closes https://github.com/official-stockfish/Stockfish/pull/5886

Bench: 2962718
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: FauziAkram
Date: Mon Feb 24 19:07:29 2025 +0100
Timestamp: 1740420449

Use neon_m128_reduce_add_epi32 for NEON vector reduction

Accomplishing the entire horizontal addition in a single NEON instruction

closes https://github.com/official-stockfish/Stockfish/pull/5885

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: FauziAkram
Date: Mon Feb 24 19:04:59 2025 +0100
Timestamp: 1740420299

Small code cleanup

Use std::is_arithmetic_v as it is the more modern and concise way to
check for arithmetic types. While at it, fixing a static assert in
misc.h, thanks to Shawn and Disservin for helping.

closes https://github.com/official-stockfish/Stockfish/pull/5883

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: Daniel Monroe
Date: Mon Feb 24 19:03:19 2025 +0100
Timestamp: 1740420199

Simplify ttcut depth condition

Simplify ttcut depth condition in a recent tweak of Nonlinear (PR #5876)

Passed simplification STC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 235328 W: 61646 L: 61644 D: 112038 Elo +0.00
Ptnml(0-2): 1039, 27947, 59676, 27977, 1025
https://tests.stockfishchess.org/tests/view/67abc7fba04df5eb8dbeb442

Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 63744 W: 16306 L: 16128 D: 31310 Elo +0.97
Ptnml(0-2): 58, 6918, 17748, 7084, 64
https://tests.stockfishchess.org/tests/view/67abd776a04df5eb8dbeb9c1

closes https://github.com/official-stockfish/Stockfish/pull/5877

Bench: 2667779
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: Carlos Esparza
Date: Mon Feb 24 19:01:23 2025 +0100
Timestamp: 1740420083

Replace hint_common_parent_position() by backwards accumulator updates

Only calls to `evaluate()` now trigger NNUE accumulator updates. To make
sure that we are likely to find parent positions from which to update
the accumulators we perform a backwards NNUE update whenever we compute
the accumulator from scratch for some position.

passed STC
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 39680 W: 10474 L: 10164 D: 19042 Elo +2.71
Ptnml(0-2): 171, 4068, 11042, 4398, 161
https://tests.stockfishchess.org/tests/view/67a27f26eb183d11c65945be

passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 337308 W: 86408 L: 85550 D: 165350 Elo +0.88
Ptnml(0-2): 276, 30551, 106126, 31441, 260
https://tests.stockfishchess.org/tests/view/67a287efeb183d11c65945ee

then simplified:
STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 28608 W: 7641 L: 7413 D: 13554 Elo +2.77
Ptnml(0-2): 132, 3036, 7744, 3256, 136
https://tests.stockfishchess.org/tests/view/67a4703719f522d3866d3345

LTC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 200226 W: 51026 L: 50990 D: 98210 Elo +0.06
Ptnml(0-2): 170, 18468, 62799, 18508, 168
https://tests.stockfishchess.org/tests/view/67a4f255229c1a170cc08964

The version in this PR is a bit different from the simplified version,
but it's compile-time changes only.

closes https://github.com/official-stockfish/Stockfish/pull/5870

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: Thu Feb 13 20:18:35 2025 +0100
Timestamp: 1739474315

FutilityValue formula tweak

Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 29600 W: 7979 L: 7662 D: 13959 Elo +3.72
Ptnml(0-2): 138, 3446, 7324, 3745, 147
https://tests.stockfishchess.org/tests/view/67ac7dff52879dfd14d7e7da

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 49662 W: 12850 L: 12502 D: 24310 Elo +2.43
Ptnml(0-2): 41, 5354, 13689, 5710, 37
https://tests.stockfishchess.org/tests/view/67acc1b252879dfd14d7e81d

closes https://github.com/official-stockfish/Stockfish/pull/5879

Bench: 2581469
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: Daniel Monroe
Date: Thu Feb 13 20:17:26 2025 +0100
Timestamp: 1739474246

Decrease lmr depth if static eval decreases a lot

This tweak originally had some more conditions which have been simplified away.

Passed STC
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 60064 W: 15797 L: 15439 D: 28828 Elo +2.07
Ptnml(0-2): 236, 7080, 15106, 7310, 300
https://tests.stockfishchess.org/tests/view/67a2af9cfedef70e42ac3325

Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 76794 W: 19740 L: 19337 D: 37717 Elo +1.82
Ptnml(0-2): 61, 8327, 21236, 8694, 79
https://tests.stockfishchess.org/tests/view/67a2c904fedef70e42ac374d

Passed Non-Regression VVLTC scaling check
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 29046 W: 7581 L: 7389 D: 14076 Elo +2.30
Ptnml(0-2): 2, 2557, 9213, 2749, 2
https://tests.stockfishchess.org/tests/view/67a54b591c4a3ea87241cb83

Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 212448 W: 55244 L: 55217 D: 101987 Elo +0.04
Ptnml(0-2): 932, 25283, 53707, 25430, 872
https://tests.stockfishchess.org/tests/view/67aaacb02554387b116f698f

Passed simplification LTC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 185736 W: 47270 L: 47217 D: 91249 Elo +0.10
Ptnml(0-2): 141, 20568, 51394, 20627, 138
https://tests.stockfishchess.org/tests/view/67ab8efa133d55b1d3bc1397

closes https://github.com/official-stockfish/Stockfish/pull/5878

Bench: 2512420
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: Nonlinear2
Date: Thu Feb 13 19:52:06 2025 +0100
Timestamp: 1739472726

Tweak the cutnode depth condition for TT cutoffs

Passed STC:
https://tests.stockfishchess.org/tests/view/67ab396ab5c93ee812d851f3
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 83648 W: 21964 L: 21571 D: 40113 Elo +1.63
Ptnml(0-2): 339, 9779, 21217, 10128, 361

Passed LTC:
https://tests.stockfishchess.org/tests/view/67ab9647133d55b1d3bc171e
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 68160 W: 17551 L: 17166 D: 33443 Elo +1.96
Ptnml(0-2): 62, 7353, 18870, 7728, 67

closes https://github.com/official-stockfish/Stockfish/pull/5876

Bench: 3087275
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: Thu Feb 13 19:49:54 2025 +0100
Timestamp: 1739472594

Do more reductions for cut nodes without a tt move

Logic is somewhat similar to IIR but in LMR.
Usually things like reducing more in IIR scale badly but this patch does
this in LMR where reducing more for cutNodes is in general good, so I
believe there is no non-linear scaling.

Passed STC:
https://tests.stockfishchess.org/tests/view/67abc9aaa04df5eb8dbeb452
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 42304 W: 11223 L: 10892 D: 20189 Elo +2.72
Ptnml(0-2): 184, 4904, 10669, 5187, 208

Passed LTC:
https://tests.stockfishchess.org/tests/view/67abcd7ba04df5eb8dbeb96c
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 32334 W: 8386 L: 8074 D: 15874 Elo +3.35
Ptnml(0-2): 26, 3446, 8916, 3748, 31

closes https://github.com/official-stockfish/Stockfish/pull/5875

Bench: 2612849
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: Stefan Geschwentner
Date: Thu Feb 13 19:46:53 2025 +0100
Timestamp: 1739472413

Refactor reduction rules

Refactor reduction rules so that all ttPv/Pv related stuff is in one
rule and the scaling becomes more clear. No functional change

closes https://github.com/official-stockfish/Stockfish/pull/5871

No functional change
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: Daniel Monroe
Date: Thu Feb 13 19:45:55 2025 +0100
Timestamp: 1739472355

Simplify opponent worsening

Passed simplification STC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 57120 W: 14712 L: 14526 D: 27882 Elo +1.13
Ptnml(0-2): 53, 6241, 15796, 6407, 63
https://tests.stockfishchess.org/tests/view/67a26153eb183d11c659454d

Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 313452 W: 79893 L: 79973 D: 153586 Elo -0.09
Ptnml(0-2): 279, 35053, 86156, 34945, 293
https://tests.stockfishchess.org/tests/view/67a29fe0fedef70e42ac32ae

closes https://github.com/official-stockfish/Stockfish/pull/5867

Bench: 2582245
see source
Windows x64 for modern computers + AVX2
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: Carlos Esparza
Date: Thu Feb 13 19:44:53 2025 +0100
Timestamp: 1739472293

Remove two xors by setting the hash keys for unreachable squares to zero

performance before:
3.6714 +- 0.20% Gcycles
3.6620 +- 0.12% Gcycles
3.6704 +- 0.26% Gcycles
3.6602 +- 0.27% Gcycles
3.6799 +- 0.37% Gcycles

after:
3.6540 +- 0.30% Gcycles
3.6388 +- 0.25% Gcycles
3.6557 +- 0.17% Gcycles
3.6449 +- 0.15% Gcycles
3.6460 +- 0.26% Gcycles

(every line is a different `profile-build` and shows the number of
cycles needed for `./stockfish bench`, measured with `perf stat -r 10`)

closes https://github.com/official-stockfish/Stockfish/pull/5754

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: Shawn Xu
Date: Wed Feb 5 19:00:25 2025 +0100
Timestamp: 1738778425

Increase PCM bonus when cutOffCnt is low

Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 36832 W: 9763 L: 9438 D: 17631 Elo +3.07
Ptnml(0-2): 159, 4267, 9254, 4562, 174
https://tests.stockfishchess.org/tests/view/67a29dbafedef70e42ac329a

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 19728 W: 5124 L: 4839 D: 9765 Elo +5.02
Ptnml(0-2): 18, 2029, 5485, 2314, 18
https://tests.stockfishchess.org/tests/view/67a2a1abfedef70e42ac32b7

closes https://github.com/official-stockfish/Stockfish/pull/5865

Bench: 3197798
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: Daniel Monroe
Date: Wed Feb 5 18:56:12 2025 +0100
Timestamp: 1738778172

Remove non-pawn material check in qsearch pruning

Passed simplification STC
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 47712 W: 12621 L: 12409 D: 22682 Elo +1.54
Ptnml(0-2): 224, 5349, 12480, 5597, 206
https://tests.stockfishchess.org/tests/view/67a1b4fb612069de394afc37

Passed rebased simplification LTC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 188274 W: 47727 L: 47677 D: 92870 Elo +0.09
Ptnml(0-2): 171, 20429, 52867, 20519, 151
https://tests.stockfishchess.org/tests/view/67a2a761fedef70e42ac3300

closes https://github.com/official-stockfish/Stockfish/pull/5866

bench 2654242
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Disservin
Date: Wed Feb 5 18:52:28 2025 +0100
Timestamp: 1738777948

Show stdout/stderr in CI/CD tests

makes it easier to fix based on warnings shown with e.g. valgrind

closes https://github.com/official-stockfish/Stockfish/pull/5862

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: Tue Feb 4 23:08:43 2025 +0100
Timestamp: 1738706923

Fixes a wrongly combined merge conflict from the previous merge wave.

Passed STC:
https://tests.stockfishchess.org/tests/view/67a288aaeb183d11c65945f1
LLR: 2.99 (-2.94,2.94) <0.00,2.00>
Total: 51424 W: 13588 L: 13237 D: 24599 Elo +2.37
Ptnml(0-2): 223, 6039, 12860, 6344, 246

Passed LTC:
https://tests.stockfishchess.org/tests/view/67a28c0aeb183d11c6594609
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 54144 W: 13900 L: 13543 D: 26701 Elo +2.29
Ptnml(0-2): 42, 5881, 14870, 6236, 43

closes https://github.com/official-stockfish/Stockfish/pull/5863

Bench: 2345723
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: Michael Chaly
Date: Tue Feb 4 21:37:11 2025 +0100
Timestamp: 1738701431

Reduce less for positions without tt move

Continuation of work on scaling.
In line with previous scaling patches this one massively reduces
reduction for moves that don't go thru lmr for position without a tt
move.

Passed VVLTC with STC bounds:
https://tests.stockfishchess.org/tests/view/679fd2450774dfd78deb12b2
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 74718 W: 19354 L: 19042 D: 36322 Elo +1.45
Ptnml(0-2): 5, 6724, 23595, 7024, 11

Passed VVLTC with LTC bounds:
https://tests.stockfishchess.org/tests/view/67a009930774dfd78deb2346
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 82638 W: 21587 L: 21212 D: 39839 Elo +1.58
Ptnml(0-2): 15, 7476, 25953, 7869, 6

closes https://github.com/official-stockfish/Stockfish/pull/5860

Bench: 2887850
see source

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