OpenChess

Author: yl25946
Date: Thu Jul 11 07:29:49 2024 +0200
Timestamp: 1720675789

removed second killer move

STC with movepicker rewrite:

LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 46656 W: 12208 L: 11995 D: 22453 Elo +1.59
Ptnml(0-2): 203, 5461, 11777, 5694, 193
https://tests.stockfishchess.org/tests/ ... 1ae5999e68

Earlier version passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 468896 W: 120999 L: 120054 D: 227843 Elo +0.70
Ptnml(0-2): 1207, 55209, 120639, 56218, 1175
https://tests.stockfishchess.org/tests/ ... 30fca58630

Earlier version passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 550524 W: 139553 L: 139877 D: 271094 Elo -0.20
Ptnml(0-2): 333, 61646, 151616, 61346, 321
https://tests.stockfishchess.org/tests/ ... 30fca586b1

closes https://github.com/official-stockfish/S ... /pull/5472

bench 1234309

Co-authored-by: rn5f107s2 <>

https://abrok.eu/stockfish/

Homayoun wrote: Thu Jul 11, 2024 8:34 pm Author: yl25946
Date: Thu Jul 11 07:29:49 2024 +0200
Timestamp: 1720675789

removed second killer move

STC with movepicker rewrite:

LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 46656 W: 12208 L: 11995 D: 22453 Elo +1.59
Ptnml(0-2): 203, 5461, 11777, 5694, 193
https://tests.stockfishchess.org/tests/ ... 1ae5999e68

Earlier version passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 468896 W: 120999 L: 120054 D: 227843 Elo +0.70
Ptnml(0-2): 1207, 55209, 120639, 56218, 1175
https://tests.stockfishchess.org/tests/ ... 30fca58630

Earlier version passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 550524 W: 139553 L: 139877 D: 271094 Elo -0.20
Ptnml(0-2): 333, 61646, 151616, 61346, 321
https://tests.stockfishchess.org/tests/ ... 30fca586b1

closes https://github.com/official-stockfish/S ... /pull/5472

bench 1234309

Co-authored-by: rn5f107s2 <>

https://abrok.eu/stockfish/

Many thanks

Best regards, Sedat.

Author: Linmiao Xu
Date: Mon Jul 15 13:38:14 2024 +0200
Timestamp: 1721043494

Separate eval params for smallnet and main net

Values found with spsa around 80% of 120k games at 60+0.6:
https://tests.stockfishchess.org/tests/ ... fcdcee3ea4

Passed STC:
https://tests.stockfishchess.org/tests/ ... be9d4e98a9
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 313696 W: 81107 L: 80382 D: 152207 Elo +0.80
Ptnml(0-2): 934, 36942, 80363, 37683, 926

Passed LTC:
https://tests.stockfishchess.org/tests/ ... be9d4e9915
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 228420 W: 57903 L: 57190 D: 113327 Elo +1.08
Ptnml(0-2): 131, 25003, 63243, 25688, 145

closes https://github.com/official-stockfish/S ... /pull/5486

bench 1319322

https://abrok.eu/stockfish/

Author: Michael Chaly
Date: Fri Jul 19 08:41:38 2024 +0200
Timestamp: 1721371298

Adjust bonus to move that caused a fail low

This is an elo gainer and simultaneously a minor logical fix to bonuses that caused a fail low.
It increases maximum of statscore based subtraction - but disallows negative bonuses.

Passed STC:
https://tests.stockfishchess.org/tests/ ... be9d4ec063
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 44640 W: 11805 L: 11472 D: 21363 Elo +2.59
Ptnml(0-2): 166, 5178, 11335, 5439, 202

Passed LTC:
https://tests.stockfishchess.org/tests/ ... be9d4ec190
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 72288 W: 18478 L: 18082 D: 35728 Elo +1.90
Ptnml(0-2): 50, 7919, 19825, 8285, 65

closes https://github.com/official-stockfish/S ... /pull/5494

Bench: 1477054

https://abrok.eu/stockfish/

Author: Linmiao Xu
Date: Tue Jul 23 19:34:27 2024 +0200
Timestamp: 1721756067

Update default main net to nn-31337bea577c.nnue

Created by updating output weights (256) and biases (8)
of the previous main net with values found with spsa around
101k / 120k games at 140+1.4.

264 spsa params: output weights and biases in nn-e8bac1c07a5a.nnue
A: 6000, alpha: 0.602, gamma: 0.101
weights: [-127, 127], c_end = 6
biases: [-8192, 8192], c_end = 64

Among the 264 params, 189 weights and all 8 biases were changed.

Changes in the weights:
- mean: -0.111 +/- 3.57
- range: [-8, 8]

Found with the same method as:
https://github.com/official-stockfish/S ... /pull/5459

Due to the original name (nn-ea8c9128c325.nnue) being too similar
to the previous main net (nn-e8bac1c07a5a.nnue) and creating confusion,
it was renamed by making non-functional changes to the .nnue file
the same way as past nets with:
https://github.com/linrock/nnue-namer

To verify that bench is the same and view the modified non-functional bytes:
```
echo -e "setoption name EvalFile value nn-ea8c9128c325.nnue\nbench" | ./stockfish
echo -e "setoption name EvalFile value nn-31337bea577c.nnue\nbench" | ./stockfish

cmp -l nn-ea8c9128c325.nnue nn-31337bea577c.nnue

diff <(xxd nn-ea8c9128c325.nnue) <(xxd nn-31337bea577c.nnue)
```

Passed STC:
https://tests.stockfishchess.org/tests/ ... be9d4ec080
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 57280 W: 15139 L: 14789 D: 27352 Elo +2.12
Ptnml(0-2): 209, 6685, 14522, 6995, 229

Passed LTC:
https://tests.stockfishchess.org/tests/ ... be9d4ec1b4
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 63030 W: 16093 L: 15720 D: 31217 Elo +2.06
Ptnml(0-2): 47, 6766, 17516, 7139, 47

closes https://github.com/official-stockfish/S ... /pull/5509

bench 1371485

Author: Shawn Xu
Date: Sun Jul 28 22:22:50 2024 +0200
Timestamp: 1722198170

Remove Killers

The removal of killers on line 1774 resulted in a substantial decrease
in pre-LMR history average, so a negative history fill is applied to
counter it.

Passed Non-regression STC (vs #5513):
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 21984 W: 5886 L: 5645 D: 10453 Elo +3.81
Ptnml(0-2): 80, 2492, 5628, 2691, 101
https://tests.stockfishchess.org/tests/ ... be9d4ecb9d

Passed Non-regression LTC (vs #5513):
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 95430 W: 24141 L: 23995 D: 47294 Elo +0.53
Ptnml(0-2): 97, 10537, 26298, 10689, 94
https://tests.stockfishchess.org/tests/ ... be9d4ecbf8

closes https://github.com/official-stockfish/S ... /pull/5517

Bench: 1660869

https://abrok.eu/stockfish/

Author: Shawn Xu
Date: Sat Aug 3 09:42:54 2024 +0200
Timestamp: 1722670974

Simplify Cutnode Reduction

Passed Non-regression STC:
LR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 143968 W: 37439 L: 37333 D: 69196 Elo +0.26
Ptnml(0-2): 521, 17228, 36456, 17182, 597
https://tests.stockfishchess.org/tests/ ... be9d4ed27f

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 198954 W: 50384 L: 50345 D: 98225 Elo +0.07
Ptnml(0-2): 201, 22360, 54347, 22337, 232
https://tests.stockfishchess.org/tests/ ... be9d4ed423

closes https://github.com/official-stockfish/S ... /pull/5526

bench 1277466
https://abrok.eu/stockfish/

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/ ... be9d4ef10e

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/ ... 509c13b2b6

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

https://abrok.eu/stockfish/?

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/S ... /pull/5548

No functional change

https://abrok.eu/stockfish/?