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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Vizvezdenec
Date: Fri Dec 25 10:21:00 2020 +0100
Timestamp: 1608888060

Do more LMR for captures

This patch enables LMR for all captures at allNodes that were not in PV.
Currently we do LMR for all captures at cutNodes so this is an expansion of this logic:
now we do LMR for all captures almost at all non-pv nodes,
excluding only allNodes that were in PV.

passed STC
https://tests.stockfishchess.org/tests/view/5fe50b9d3932f79192d3973c
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 83128 W: 7606 L: 7368 D: 68154 Elo +0.99
Ptnml(0-2): 292, 5905, 28939, 6129, 299

passed LTC
https://tests.stockfishchess.org/tests/view/5fe552e43932f79192d39744
LLR: 2.92 (-2.94,2.94) {0.25,1.25}
Total: 13968 W: 568 L: 466 D: 12934 Elo +2.54
Ptnml(0-2): 5, 418, 6043, 506, 12

closes https://github.com/official-stockfish/Stockfish/pull/3273

Bench: 4194835
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Moez Jellouli
Date: Wed Dec 23 20:20:24 2020 +0100
Timestamp: 1608751224

Correct Outflanking calculations in classical eval

Take signed value of rank difference between kings squares instead absolute value in outflanking calculation. This change correct evaluation of endgames with one king invading opponent last ranks.

Passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 122240 W: 24326 L: 23896 D: 74018 Elo +1.22
Ptnml(0-2): 2101, 14139, 28236, 14517, 2127
https://tests.stockfishchess.org/tests/view/5fdfc33a3932f79192d394b8

Passed LTC:
LLR: 2.97 (-2.94,2.94) {0.25,1.25}
Total: 157416 W: 20870 L: 20292 D: 116254 Elo +1.28
Ptnml(0-2): 973, 13954, 48333, 14418, 1030
https://tests.stockfishchess.org/tests/view/5fe07a453932f79192d39502

closes https://github.com/official-stockfish/Stockfish/pull/3271

Bench: 4162769
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
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 Dec 23 20:17:57 2020 +0100
Timestamp: 1608751077

Tweak the formulas for unsafeSquares

We give more bonus for a special case: If there are some enemy squares occupied
or attacked by the enemy on the passed pawn span,
but if they are all attacked by our pawn, use new intermediate factor 30.

The main credit goes to Rocky for the idea, with additional tuning and tests.

Passed STC:
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 96464 W: 19233 L: 18834 D: 58397 Elo +1.44
Ptnml(0-2): 1683, 11327, 21950, 11452, 1820
https://tests.stockfishchess.org/tests/view/5fdd21ab3932f79192d39357

Passed LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 81320 W: 10784 L: 10352 D: 60184 Elo +1.85
Ptnml(0-2): 602, 7524, 24044, 7820, 670
https://tests.stockfishchess.org/tests/view/5fddec983932f79192d393a4

closes https://github.com/official-stockfish/Stockfish/pull/3268

Bench: 4338972
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: pb00067
Date: Fri Dec 18 21:19:46 2020 +0100
Timestamp: 1608322786

Simplify condition for assigning static-eval based bonus

for quiet move ordering and simplify bonus formula.

Due to clamping the bonus to relative low values the impact on high
depths is minimal, thus the restriction to low depths seems not
necessary.
Also the condition of movecount in previous node seems to be not
determinant.

Passed STC:
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 14600 W: 1424 L: 1323 D: 11853 Elo +2.40
Ptnml(0-2): 55, 1033, 5020, 1140, 52
https://tests.stockfishchess.org/tests/view/5fd67b381ac16912018885ec

Passed LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 85008 W: 3218 L: 3206 D: 78584 Elo +0.05
Ptnml(0-2): 49, 2840, 36700, 2880, 35
https://tests.stockfishchess.org/tests/view/5fd6af041ac16912018885f8

closes https://github.com/official-stockfish/Stockfish/pull/3265

bench: 4524994
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
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 Dec 18 21:17:34 2020 +0100
Timestamp: 1608322654

Adjust definition of unsafeSquares

and adjust related bonus values. The bonus is now not given whenever
there is an enemy piece in front of the pawn.

Passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 109472 W: 22097 L: 21673 D: 65702 Elo +1.35
Ptnml(0-2): 2111, 12800, 24482, 13240, 2103
https://tests.stockfishchess.org/tests/view/5fd8d3740c5870924361ffad

Passed LTC:
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 39384 W: 5334 L: 4990 D: 29060 Elo +3.03
Ptnml(0-2): 279, 3648, 11535, 3910, 320
https://tests.stockfishchess.org/tests/view/5fd971ab0c5870924361fff0

closes https://github.com/official-stockfish/Stockfish/pull/3266

Bench: 4488955
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Vizvezdenec
Date: Mon Dec 14 07:52:02 2020 +0100
Timestamp: 1607928722

Increase reduction in case of stable best move

The idea of this patch is pretty simple - we already do more reductions
for non-PV and root nodes in case of stable best move for depth > 10.
This patch makes us do so if root depth if > 10 instead, which
is logical since best move changes (thus instability of it) is
counted at root, so it makes a lot of sense to use depth of the root.

passed STC
https://tests.stockfishchess.org/tests/view/5fd643271ac16912018885c5
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 13232 W: 1308 L: 1169 D: 10755 Elo +3.65
Ptnml(0-2): 39, 935, 4535, 1062, 45

passed LTC
https://tests.stockfishchess.org/tests/view/5fd68db11ac16912018885f0
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 14024 W: 565 L: 463 D: 12996 Elo +2.53
Ptnml(0-2): 3, 423, 6062, 517, 7

closes https://github.com/official-stockfish/Stockfish/pull/3263

Bench: 4050630
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: pb00067
Date: Mon Dec 14 07:48:48 2020 +0100
Timestamp: 1607928528

Merge static history into main history,

thus simplifying and reducing the memory footprint.
I believe using static diff for better move ordering is more suited for
low depths, so restrict writing to low depths.

Todo: probably the condition for writing can be simplified

LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 18752 W: 768 L: 705 D: 17279 Elo +1.17
Ptnml(0-2): 7, 635, 8034, 688, 12
https://tests.stockfishchess.org/tests/view/5fd631791ac169120188859e

STC:
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 36504 W: 3380 L: 3313 D: 29811 Elo +0.64
Ptnml(0-2): 116, 2667, 12645, 2682, 142
https://tests.stockfishchess.org/tests/view/5fd5ed861ac1691201888569

closes https://github.com/official-stockfish/Stockfish/pull/3262

bench: 4018036
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: mstembera
Date: Mon Dec 14 07:46:15 2020 +0100
Timestamp: 1607928375

AVX512, AVX2 and SSSE3 speedups

Improves throughput by summing 2 intermediate dot products using 16 bit addition before upconverting to 32 bit.

Potential saturation is detected and the code-path is avoided in this case.
The saturation can't happen with the current nets,
but nets can be constructed that trigger this check.

STC https://tests.stockfishchess.org/tests/view/5fd40a861ac1691201888479
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 25544 W: 2451 L: 2296 D: 20797 Elo +2.11
Ptnml(0-2): 92, 1761, 8925, 1888, 106

about 5% speedup

closes https://github.com/official-stockfish/Stockfish/pull/3261

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
Windows 32
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 12 09:31:28 2020 +0100
Timestamp: 1607761888

New Imbalance Tables Tweak

Imbalance tables tweaked to contain MiddleGame and Endgame values, instead of a single value.

The idea started from Fisherman, which requested my help to tune the values back in June/July,
so I tuned the values back then, and we were able to accomplish good results,
but not enough to pass both STC and LTC tests.

So after the recent changes, I decided to give it another shot, and I am glad that it was a successful attempt.

A special thanks goes also to mstembera, which notified me a simple way to let the patch perform a little better.

Passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 115976 W: 23124 L: 22695 D: 70157 Elo +1.29
Ptnml(0-2): 2074, 13652, 26285, 13725, 2252
https://tests.stockfishchess.org/tests/view/5fc92d2d42a050a89f02ccc8

Passed LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 156304 W: 20617 L: 20024 D: 115663 Elo +1.32
Ptnml(0-2): 1138, 14647, 46084, 15050, 1233
https://tests.stockfishchess.org/tests/view/5fc9fee142a050a89f02cd3e

closes https://github.com/official-stockfish/Stockfish/pull/3255

Bench: 4278746
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Fanael Linithien
Date: Sat Dec 12 09:20:15 2020 +0100
Timestamp: 1607761215

Use arithmetic right shift for sign extension in MMX and SSE2 paths

This appears to be slightly faster than using a comparison against zero
to compute the high bits, on both old (like Pentium III) and new (like
Zen 2) hardware.

closes https://github.com/official-stockfish/Stockfish/pull/3254

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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Vizvezdenec
Date: Sat Dec 5 16:58:42 2020 +0100
Timestamp: 1607183922

Add comments to uncommented parts of code

https://github.com/official-stockfish/Stockfish/pull/3250

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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Vizvezdenec
Date: Sat Dec 5 16:48:33 2020 +0100
Timestamp: 1607183313

Introduce static history

The idea of this patch can be described as following: we update static
history stats based on comparison of the static evaluations of the
position before and after the move. If the move increases static evaluation
it's assigned positive bonus, if it decreases static evaluation
it's assigned negative bonus. These stats are used in movepicker
to sort quiet moves.

passed STC
https://tests.stockfishchess.org/tests/view/5fca4c0842a050a89f02cd66
LLR: 3.00 (-2.94,2.94) {-0.25,1.25}
Total: 78152 W: 7409 L: 7171 D: 63572 Elo +1.06
Ptnml(0-2): 303, 5695, 26873, 5871, 334

passed LTC
https://tests.stockfishchess.org/tests/view/5fca6be442a050a89f02cd75
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 40240 W: 1602 L: 1441 D: 37197 Elo +1.39
Ptnml(0-2): 19, 1306, 17305, 1475, 15

closes https://github.com/official-stockfish/Stockfish/pull/3253

bench 3845156
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: SFisGOD
Date: Sun Nov 29 16:54:06 2020 +0100
Timestamp: 1606665246

Update default net to nn-62ef826d1a6d.nnue

Include scaling change as suggested by Dietrich Kappe,
the one who trained net for Komodo. According to him,
some nets may require different scaling in order to utilize its full strength.

STC:
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 99856 W: 9669 L: 9401 D: 80786 Elo +0.93
Ptnml(0-2): 374, 7468, 34037, 7614, 435
https://tests.stockfishchess.org/tests/view/5fc2697642a050a89f02c8ec

LTC:
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 29840 W: 1220 L: 1081 D: 27539 Elo +1.62
Ptnml(0-2): 10, 969, 12827, 1100, 14
https://tests.stockfishchess.org/tests/view/5fc2ea5142a050a89f02c957

Bench: 3561701
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Unai Corzo
Date: Sun Nov 29 16:52:51 2020 +0100
Timestamp: 1606665171

Reductions simplification

Simplify increase reduction for captures/promotions if late move and at low depth.

STC https://tests.stockfishchess.org/tests/view/5fbff65067cbf42301d6b3ae
LLR: 2.97 (-2.94,2.94) {-1.25,0.25}
Total: 49088 W: 4607 L: 4555 D: 39926 Elo +0.37
Ptnml(0-2): 177, 3615, 16932, 3619, 201

LTC https://tests.stockfishchess.org/tests/view/5fc0902967cbf42301d6b3fc
LLR: 2.99 (-2.94,2.94) {-0.75,0.25}
Total: 160944 W: 6153 L: 6193 D: 148598 Elo -0.09
Ptnml(0-2): 90, 5525, 69294, 5461, 102

closes https://github.com/official-stockfish/Stockfish/pull/3248

bench: 3834568
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: syzygy1
Date: Sun Nov 29 16:51:01 2020 +0100
Timestamp: 1606665061

Remove piece lists

This patch removes the incrementally updated piece lists from the Position object.

This has been tried before but always failed. My reasons for trying again are:

* 32-bit systems (including phones) are now much less important than they were some years ago (and are absent from fishtest);
* NNUE may have made SF less finely tuned to the order in which moves were generated.

STC:
LLR: 2.94 (-2.94,2.94) {-1.25,0.25}
Total: 55272 W: 5260 L: 5216 D: 44796 Elo +0.28
Ptnml(0-2): 208, 4147, 18898, 4159, 224
https://tests.stockfishchess.org/tests/view/5fc2986a42a050a89f02c926

LTC:
LLR: 2.96 (-2.94,2.94) {-0.75,0.25}
Total: 16600 W: 673 L: 608 D: 15319 Elo +1.36
Ptnml(0-2): 14, 533, 7138, 604, 11
https://tests.stockfishchess.org/tests/view/5fc2f98342a050a89f02c95c

closes https://github.com/official-stockfish/Stockfish/pull/3247

Bench: 3940967
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Unai Corzo
Date: Sun Nov 29 16:47:00 2020 +0100
Timestamp: 1606664820

Update README.md

fix a few typos

closes https://github.com/official-stockfish/Stockfish/pull/3245

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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Unai Corzo
Date: Sun Nov 29 16:42:40 2020 +0100
Timestamp: 1606664560

Search simplification

STC https://tests.stockfishchess.org/tests/view/5fc2083942a050a89f02c8bb
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 23200 W: 2251 L: 2160 D: 18789 Elo +1.36
Ptnml(0-2): 86, 1726, 7895, 1797, 96

LTC https://tests.stockfishchess.org/tests/view/5fc22d7b42a050a89f02c8d0
LLR: 2.92 (-2.94,2.94) {-0.75,0.25}
Total: 15832 W: 653 L: 590 D: 14589 Elo +1.38
Ptnml(0-2): 7, 521, 6795, 588, 5

closes https://github.com/official-stockfish/Stockfish/pull/3244/files

bench: 3827317

Simplify search.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: lonfom169
Date: Sun Nov 29 16:40:06 2020 +0100
Timestamp: 1606664406

Remove bonus for killers.

Passed non-regression STC:
LLR: 2.94 (-2.94,2.94) {-1.25,0.25}
Total: 14712 W: 1416 L: 1315 D: 11981 Elo +2.39
Ptnml(0-2): 59, 1029, 5082, 1124, 62
https://tests.stockfishchess.org/tests/view/5fbfa31f67cbf42301d6b36e

Passed non-regression LTC:
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 27536 W: 1099 L: 1044 D: 25393 Elo +0.69
Ptnml(0-2): 11, 929, 11838, 974, 16
https://tests.stockfishchess.org/tests/view/5fbfac9167cbf42301d6b371

closes https://github.com/official-stockfish/Stockfish/pull/3241

Bench: 3887644
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Lolligerhans
Date: Sun Nov 29 16:38:03 2020 +0100
Timestamp: 1606664283

Refine rook penalty on closed files

+-----------------+
| . . . . . . . . | All files are closed. Some files are
| . . . . . o o . | more valuable for rooks, because
| . . . . o . . o | they might open in the future.
| . . . o x . . x |
| o . o x . x x . |
| x o x . . . . . | x our pawns
| . x . . . . . . | o their pawns
| . . . . . . . . | ^ rooks are scored higher on these files
+-----------------+
^ ^

Files containing none of our own pawns are open or half-open (otherwise
they are closed). Rooks on (half-)open files recieve a bonus for the
future potential to act along all ranks.

This commit refines the (relative) penalty of rooks on closed files.
Files that contain one of our blocked pawns are considered less likely
to open in the future; rooks on these files are now penalized stronger.

This bonus does not generally correlate with mobility. If the condition
is sufficiently refined in the future, it may be beneficial to adjust or
override mobility scores in some cases.

LTC
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 494384 W: 71565 L: 70231 D: 352588 Elo +0.94
Ptnml(0-2): 3907, 48050, 142118, 49036, 4081
https://tests.stockfishchess.org/tests/view/5fb9312e67cbf42301d6afb9

LTC (non-regression w/ book noob_3moves.epd)
LLR: 2.95 (-2.94,2.94) {-0.75,0.25}
Total: 208520 W: 27044 L: 26937 D: 154539 Elo +0.18
Ptnml(0-2): 1557, 19850, 61391, 19853, 1609
https://tests.stockfishchess.org/tests/view/5fc01ced67cbf42301d6b3df

STC
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 98392 W: 20269 L: 19868 D: 58255 Elo +1.42
Ptnml(0-2): 1804, 11297, 22589, 11706, 1800
https://tests.stockfishchess.org/tests/view/5fb7f88a67cbf42301d6af10

closes https://github.com/official-stockfish/Stockfish/pull/3242

Bench: 3682630
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: mstembera
Date: Sun Nov 29 16:36:49 2020 +0100
Timestamp: 1606664209

Cleaned up MakeIndex()

The index order in kpp_board_index[][] is reversed to be more optimal for the access pattern

STC https://tests.stockfishchess.org/tests/view/5fbd74f967cbf42301d6b24f
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 27504 W: 2686 L: 2607 D: 22211 Elo +1.00
Ptnml(0-2): 84, 2001, 9526, 2034, 107

closes https://github.com/official-stockfish/Stockfish/pull/3233

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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Vizvezdenec
Date: Thu Nov 26 08:20:06 2020 +0100
Timestamp: 1606375206

use classical for certain endgames.

STC https://tests.stockfishchess.org/tests/view/5fbc64c067cbf42301d6b1d6
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 53360 W: 5223 L: 5024 D: 43113 Elo +1.30
Ptnml(0-2): 184, 3877, 18390, 4014, 215

LTC https://tests.stockfishchess.org/tests/view/5fbc97f267cbf42301d6b1ee
LLR: 2.96 (-2.94,2.94) {0.25,1.25}
Total: 126472 W: 5111 L: 4766 D: 116595 Elo +0.95
Ptnml(0-2): 50, 4032, 54749, 4333, 72

closes https://github.com/official-stockfish/Stockfish/pull/3240

bench: 3820648
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: MaximMolchanov
Date: Wed Nov 25 21:10:13 2020 +0100
Timestamp: 1606335013

Calculate sum from first elements

in affine transform for AVX512/AVX2/SSSE3

The idea is to initialize sum with the first element instead of zero.
Reduce one add_epi32 and one set_zero SIMD instructions for each output dimension.

sum = 0; for i = 1 to n sum += a[i] ->
sum = a[1]; for i = 2 to n sum += a[i]

STC:
LLR: 2.95 (-2.94,2.94) {-0.25,1.25}
Total: 69048 W: 7024 L: 6799 D: 55225 Elo +1.13
Ptnml(0-2): 260, 5175, 23458, 5342, 289
https://tests.stockfishchess.org/tests/view/5faf2cf467cbf42301d6aa06

closes https://github.com/official-stockfish/Stockfish/pull/3227

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
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Unai Corzo
Date: Wed Nov 25 21:05:08 2020 +0100
Timestamp: 1606334708

Assorted search and eval parameter tune

Search and eval parameter tune.

STC https://tests.stockfishchess.org/tests/view/5fba850a67cbf42301d6b07d
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 24312 W: 2388 L: 2228 D: 19696 Elo +2.29
Ptnml(0-2): 85, 1800, 8241, 1930, 100

LTC https://tests.stockfishchess.org/tests/view/5fbad5ea67cbf42301d6b0fa
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 88376 W: 3619 L: 3351 D: 81406 Elo +1.05
Ptnml(0-2): 56, 2977, 37849, 3255, 51

closes https://github.com/official-stockfish/Stockfish/pull/3232

bench: 3600361
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers + AVX2
Windows x64 for modern computers
Windows x64 + SSSE3
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers + AVX2
Linux x64 for modern computers
Linux x64 + SSSE3
Linux x64
Author: Stéphane Nicolet
Date: Mon Nov 23 22:20:32 2020 +0100
Timestamp: 1606166432

Small cleanups 13

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
Windows 32
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 15 13:23:19 2020 +0100
Timestamp: 1605442999

Rook Mobility Tweak

Passed STC:
LLR: 2.94 (-2.94,2.94) {-0.25,1.25}
Total: 171152 W: 34715 L: 34202 D: 102235 Elo +1.04
Ptnml(0-2): 3278, 20155, 38228, 20606, 3309
https://tests.stockfishchess.org/tests/view/5fa861f467cbf42301d6a68e

Passed LTC:
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 149616 W: 20471 L: 19882 D: 109263 Elo +1.37
Ptnml(0-2): 1172, 14434, 43102, 14833, 1267
https://tests.stockfishchess.org/tests/view/5fa9c8ff67cbf42301d6a74f

closes https://github.com/official-stockfish/Stockfish/pull/3226

Bench: 3597730
see source

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