Stockfish

[Homayoun]

Author: Muzhen Gaming
Date: Mon Oct 30 07:51:27 2023 +0100
Timestamp: 1698648687

Introduce asymmetric optimism

Introduce asymmetric optimism for both side to move and opponent. Parameter tuning was done with 200k LTC games.

STC: https://tests.stockfishchess.org/tests/ ... e8395622b3
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 98336 W: 25074 L: 24661 D: 48601 Elo +1.46
Ptnml(0-2): 339, 11612, 24890, 11951, 376

LTC: https://tests.stockfishchess.org/tests/ ... e839563140
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 83244 W: 20760 L: 20339 D: 42145 Elo +1.76
Ptnml(0-2): 51, 9306, 22498, 9705, 62

closes https://github.com/official-stockfish/S ... /pull/4853

Bench: 1371690

https://abrok.eu/stockfish/

[OrgZ]

[Homayoun]

[Homayoun]

Author: Michael Chaly
Date: Fri Nov 3 22:50:05 2023 +0100
Timestamp: 1699048205

Update pawn history based on static eval difference

Use the same logic as in main history but with 1/4 multiplier.

Passed STC:
https://tests.stockfishchess.org/tests/ ... e8395615bf
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 306624 W: 77811 L: 77094 D: 151719 Elo +0.81
Ptnml(0-2): 975, 36411, 77830, 37114, 982

Passed LTC:
https://tests.stockfishchess.org/tests/ ... e83956818d
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 99150 W: 24681 L: 24228 D: 50241 Elo +1.59
Ptnml(0-2): 56, 11107, 26792, 11568, 52

closes https://github.com/official-stockfish/S ... /pull/4859

bench 1330590
https://abrok.eu/stockfish/

[Sedat Canbaz]

Author: Michael Chaly
Date: Fri Nov 3 22:50:05 2023 +0100
Timestamp: 1699048205

Update pawn history based on static eval difference

Use the same logic as in main history but with 1/4 multiplier.

Passed STC:
https://tests.stockfishchess.org/tests/ ... e8395615bf
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 306624 W: 77811 L: 77094 D: 151719 Elo +0.81
Ptnml(0-2): 975, 36411, 77830, 37114, 982

Passed LTC:
https://tests.stockfishchess.org/tests/ ... e83956818d
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 99150 W: 24681 L: 24228 D: 50241 Elo +1.59
Ptnml(0-2): 56, 11107, 26792, 11568, 52

closes https://github.com/official-stockfish/S ... /pull/4859

bench 1330590
https://abrok.eu/stockfish/

Dear Mr. Homayoun,

Many thanks for all the news updates...

Greetings )

[Homayoun]

Dear Mr. Homayoun,

Many thanks for all the news updates...

Greetings )
[/quote]
Thanks , too. Mr. Sedat.

[STUDENT_MASTER]

BOOM!

Author: FauziAkram
Date: Sat Nov 4 17:34:35 2023 +0100
Timestamp: 1699115675

Tweaking the futility pruning formula

Huge credit goes also to candirufish,
as the idea was first tried by him, and then tuned by me at multiple phases.

Tweaking the futility pruning formula to be a bit more selective about when pruning is applied.
Adjust the value added to the static eval based on the bestValue relative to ss->staticEval. If bestValue is significantly lower, we add a larger value.

Passed STC:
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 37120 W: 9590 L: 9266 D: 18264 Elo +3.03
Ptnml(0-2): 130, 4301, 9385, 4603, 141
https://tests.stockfishchess.org/tests/ ... c573523247

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 49632 W: 12381 L: 12033 D: 25218 Elo +2.44
Ptnml(0-2): 30, 5429, 13549, 5779, 29
https://tests.stockfishchess.org/tests/ ... c573523a3c

closes https://github.com/official-stockfish/S ... /pull/4861

bench: 1107118
see source

[Homayoun]

Thanks

[Homayoun]

Author: Stefan Geschwentner
Date: Tue Nov 7 08:28:43 2023 +0100
Timestamp: 1699342123

Double weight of pawn history for quiet move ordering.

I measured on my 1000 position bench the average additional added pawn history per depth.
This shows on average negative value with even smaller values with increaing depth.

A linear regression against depth get following formula:

-1960 - 130 * depth

For compensation add this to the used sort limit to maintain roughly the same proportion of sorted quiet moves.

Remarks:
1. using no compensation failed here https://tests.stockfishchess.org/tests/ ... c5735265f0
2. using only the compensation failed at LTC:
passed STC: https://tests.stockfishchess.org/tests/ ... c5735266f8
failed LTC: https://tests.stockfishchess.org/tests/ ... c573527d1c

STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 98528 W: 25109 L: 24699 D: 48720 Elo +1.45
Ptnml(0-2): 334, 11586, 25009, 12006, 329
https://tests.stockfishchess.org/tests/ ... c5735264f7

LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 69726 W: 17467 L: 17073 D: 35186 Elo +1.96
Ptnml(0-2): 39, 7814, 18769, 8196, 45

Bench: 1379422
https://abrok.eu/stockfish/

[Homayoun]

Author: Linmiao Xu
Date: Sat Nov 11 15:26:56 2023 +0100
Timestamp: 1699712816

Simplify away optimism average score offset params

Passed non-regression STC:
https://tests.stockfishchess.org/tests/ ... c57352ac4b
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 49664 W: 12687 L: 12477 D: 24500 Elo +1.47
Ptnml(0-2): 138, 5840, 12703, 5976, 175

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/ ... c57352b961
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 347166 W: 85561 L: 85676 D: 175929 Elo -0.12
Ptnml(0-2): 206, 39569, 94150, 39450, 208

closes https://github.com/official-stockfish/S ... /pull/4871

bench 1257641
https://abrok.eu/stockfish/