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Author SHA1 Message Date
FauziAkram
a615efb19f Simplify Time Management 
Instead of having a formula for using extra time with larger increments.
Simply set it to 1 when the increment is lower than 0.5s and to 1.1 when
the increment is higher.

The values can later on be further improved.

Passed STC:
https://tests.stockfishchess.org/tests/view/65d25d3c1d8e83c78bfd9293
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 27488 W: 7077 L: 6848 D: 13563
Ptnml(0-2): 96, 3041, 7267, 3218, 122

Passed LTC:
https://tests.stockfishchess.org/tests/view/65d2a72c1d8e83c78bfd97fa
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 137568 W: 34612 L: 34512 D: 68444
Ptnml(0-2): 60, 14672, 39221, 14770, 61

Passed VLTC:
https://tests.stockfishchess.org/tests/view/65d7d7d39b2da0226a5a205b
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 139650 W: 35229 L: 35134 D: 69287
Ptnml(0-2): 33, 14227, 41218, 14306, 41

Passed also the TCEC TC style suggested by vondele:
https://tests.stockfishchess.org/tests/view/65e4ca73416ecd92c162a57d
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 134150 W: 34278 L: 34163 D: 65709
Ptnml(0-2): 561, 15727, 34444, 15722, 621

closes https://github.com/official-stockfish/Stockfish/pull/5076

Bench: 1553115
 2024-03-07 19:49:01 +01:00
Gahtan Nahdi
b0ac8a4e3b Simplify extension when ttMove is assumed to fail high over current beta 
Simplify extension value to -3 when ttMove is assumed to fail high over current beta.

Passed non-reg STC:
https://tests.stockfishchess.org/tests/view/65d66ed81d8e83c78bfddcba
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 235136 W: 60711 L: 60708 D: 113717
Ptnml(0-2): 969, 27904, 59874, 27797, 1024

Passed non-reg LTC:
https://tests.stockfishchess.org/tests/view/65da2994944f2a78d4733107
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 662850 W: 166161 L: 166602 D: 330087
Ptnml(0-2): 394, 74895, 181274, 74482, 380

closes https://github.com/official-stockfish/Stockfish/pull/5088

Bench: 1553115
 2024-03-03 15:45:13 +01:00
Gahtan Nahdi
6d0d430860 Simplify IIR 
Simplified depth reduction for PV nodes without a ttMove to 3.

Passed STC non-reg:
https://tests.stockfishchess.org/tests/view/65d1a90a1d8e83c78bfd855a
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 363168 W: 93648 L: 93791 D: 175729
Ptnml(0-2): 1557, 43692, 91221, 43565, 1549

Passed LTC non-reg:
https://tests.stockfishchess.org/tests/view/65d5612d1d8e83c78bfdc8e2
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 58818 W: 14946 L: 14761 D: 29111
Ptnml(0-2): 36, 6595, 15962, 6780, 36

closes https://github.com/official-stockfish/Stockfish/pull/5062

Bench: 1505827
 2024-03-03 15:42:17 +01:00
mstembera
7831131591 Only evaluate the PSQT part of the small net for large evals. 
Thanks to Viren6 for suggesting to set complexity to 0.

STC https://tests.stockfishchess.org/tests/view/65d7d6709b2da0226a5a203f
LLR: 2.92 (-2.94,2.94) <0.00,2.00>
Total: 328384 W: 85316 L: 84554 D: 158514
Ptnml(0-2): 1414, 39076, 82486, 39766, 1450

LTC https://tests.stockfishchess.org/tests/view/65dce6d290f639b028a54d2e
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 165162 W: 41918 L: 41330 D: 81914
Ptnml(0-2): 102, 18332, 45124, 18922, 101

closes https://github.com/official-stockfish/Stockfish/pull/5083

bench: 1504003
 2024-03-03 15:29:58 +01:00
Disservin
0a3eb1d8fa Document TT code more 
Slight refactor of the TT code with the goal to make it easier to understand / tweak.

Passed Non-Regression STC:
https://tests.stockfishchess.org/tests/view/65d51e401d8e83c78bfdc427
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 56416 W: 14750 L: 14550 D: 27116
Ptnml(0-2): 227, 6386, 14796, 6558, 241

closes https://github.com/official-stockfish/Stockfish/pull/5061

No functional change
 2024-03-03 15:21:57 +01:00
Gahtan Nahdi
f77eddfa2f Join conditions for move sorting heuristics 
closes https://github.com/official-stockfish/Stockfish/pull/5078

No functional change.
 2024-03-03 15:18:13 +01:00
Disservin
abcc090a62 Restore development 
closes https://github.com/official-stockfish/Stockfish/pull/5073

No functional change
 2024-03-03 15:01:29 +01:00
Disservin
e67cc979fd Stockfish 16.1 
Official release version of Stockfish 16.1

Bench: 1303971

---

Stockfish 16.1

Today, we have the pleasure to announce Stockfish 16.1. As always, you can
freely download it at https://stockfishchess.org/download and use it in the GUI
of your choice[1].

Don't forget to join our Discord server[2] to get in touch with the community of
developers and users of the project!

*Quality of chess play*

In our testing against its predecessor, Stockfish 16.1 shows a notable
improvement in performance, with an Elo gain of up to 27 points and winning over
2 times more game pairs[3] than it loses.

*Update highlights*

*Improved evaluation*

- Updated neural network architecture: The neural network architecture has
  undergone two updates and is currently in its 8th version[4].
- Removal of handcrafted evaluation (HCE): This release marks the removal of the
  traditional handcrafted evaluation and the transition to a fully neural
  network-based approach[5].
- Dual NNUE: For the first time, Stockfish includes a secondary neural
  network[6], used to quickly evaluate positions that are easily decided.

*UCI Options removed*

`Use NNUE` and `UCI_AnalyseMode`[7] have been removed as they no longer had any
effect. `SlowMover`[8] has also been removed in favor of `Move Overhead`.

*More binaries*

We now offer 13 new binaries. These new binaries include `avx512`, `vnni256`,
`vnni512`, `m1-apple-silicon`, and `armv8-dotprod`, which take advantage of
specific CPU instructions for improved performance.
For most users, using `sse41-popcnt` (formerly `modern`), `avx2`, or `bmi2`
should be enough, but if your CPU supports these new instructions, feel free to
try them!

*Development changes*

- Updated testing book: This new book[9], now derived exclusively from the open
  Lichess database[10], is 10 times larger than its predecessor, and has been
  used to test potential improvements to Stockfish over the past few months.
- Consolidation of repositories: Aiming to simplify access to our resources, we
  have moved most Stockfish-related repositories into the official Stockfish
  organization[11] on GitHub.
- Growing maintainer team: We welcome Disservin[12] to the team of maintainers
  of the project! This extra pair of hands will ensure the lasting success of
  Stockfish.

*Thank you*

The Stockfish project builds on a thriving community of enthusiasts (thanks
everybody!) who contribute their expertise, time, and resources to build a free
and open-source chess engine that is robust, widely available, and very strong.

We would like to express our gratitude for the 10k stars[13] that light up our
GitHub project! Thank you for your support and encouragement – your recognition
means a lot to us.

We invite our chess fans to join the Fishtest testing framework[14], and
programmers to contribute to the project either directly to Stockfish[15] (C++),
to Fishtest[16] (HTML, CSS, JavaScript, and Python), to our trainer
nnue-pytorch[17] (C++ and Python), or to our website[18] (HTML, CSS/SCSS, and
JavaScript).

The Stockfish team

[1] https://github.com/official-stockfish/Stockfish/wiki/Download-and-usage#download-a-chess-gui
[2] https://discord.gg/GWDRS3kU6R
[3] https://tests.stockfishchess.org/tests/view/65d666051d8e83c78bfddbd8
[4] https://github.com/official-stockfish/nnue-pytorch/blob/master/docs/nnue.md#sfnnv8-architecture
[5] https://github.com/official-stockfish/Stockfish/commit/af110e0
[6] https://github.com/official-stockfish/Stockfish/commit/584d9ef
[7] https://github.com/official-stockfish/Stockfish/commit/c53d2ec
[8] https://github.com/official-stockfish/Stockfish/commit/536d692
[9] https://github.com/official-stockfish/books/commit/426eca4
[10] https://database.lichess.org/
[11] https://github.com/official-stockfish/
[12] https://github.com/Disservin
[13] https://github.com/official-stockfish/Stockfish/stargazers
[14] https://github.com/official-stockfish/fishtest/wiki/Running-the-worker
[15] https://github.com/official-stockfish/Stockfish
[16] https://github.com/official-stockfish/fishtest
[17] https://github.com/official-stockfish/nnue-pytorch
[18] https://github.com/official-stockfish/stockfish-web
 2024-02-24 18:15:04 +01:00
Robert Nurnberg @ elitebook
5c2b385957 Update the WDL model 
Based on 130M positions from 2.1M games.

```
Look recursively in directory pgns for games from SPRT tests using books
matching "UHO_4060_v..epd|UHO_Lichess_4852_v1.epd" for SF revisions
between 8e75548f2a (from 2024-02-17
17:11:46 +0100) and HEAD (from 2024-02-17 17:13:07 +0100). Based on
127920843 positions from 2109240 games, NormalizeToPawnValue should
change from 345 to 356.
```

The patch only affects the UCI-reported cp and wdl values.

closes https://github.com/official-stockfish/Stockfish/pull/5070

No functional change
 2024-02-24 17:59:41 +01:00
Disservin
d07033d5da Expose EvalFileSmall option for small net 
Since https://github.com/official-stockfish/fishtest/pull/1870 has been merged
it's time for this update.

5k Fixed Games showed no problems.
https://tests.stockfishchess.org/tests/view/65d9cc274c0e22b904f574d7

closes https://github.com/official-stockfish/Stockfish/pull/5068

No functional change
 2024-02-24 17:57:49 +01:00
cj5716
fc41f64dfd Simplify PV node reduction 
Reduce less on PV nodes even with an upperbound TT entry.

Passed STC:
https://tests.stockfishchess.org/tests/view/65cb3a861d8e83c78bfd0497
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 118752 W: 30441 L: 30307 D: 58004
Ptnml(0-2): 476, 14179, 29921, 14335, 465

Passed LTC:
https://tests.stockfishchess.org/tests/view/65cd3b951d8e83c78bfd2b0d
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 155058 W: 38549 L: 38464 D: 78045
Ptnml(0-2): 85, 17521, 42219, 17632, 72

closes https://github.com/official-stockfish/Stockfish/pull/5057

Bench: 1303971
 2024-02-17 17:13:07 +01:00
Linmiao Xu
8e75548f2a Update default main net to nn-b1a57edbea57.nnue 
Created by retraining the previous main net `nn-baff1edbea57.nnue` with:
- some of the same options as before: ranger21, more WDL skipping
- the addition of T80 nov+dec 2023 data
- increasing loss by 15% when prediction is too high, up from 10%
- use of torch.compile to speed up training by over 25%

```yaml
experiment-name: 2560--S9-514G-T80-augtodec2023-more-wdl-skip-15p-more-loss-high-q-sk28

training-dataset:
  # https://github.com/official-stockfish/Stockfish/pull/4782
  - /data/S6-514G-1ee1aba5ed.binpack
  - /data/test80-aug2023-2tb7p.v6.min.binpack
  - /data/test80-sep2023-2tb7p.binpack
  - /data/test80-oct2023-2tb7p.binpack
  - /data/test80-nov2023-2tb7p.binpack
  - /data/test80-dec2023-2tb7p.binpack
early-fen-skipping: 28

start-from-engine-test-net: True
nnue-pytorch-branch: linrock/nnue-pytorch/r21-more-wdl-skip-15p-more-loss-high-q-torch-compile

num-epochs: 1000
lr: 4.375e-4
gamma: 0.995
start-lambda: 1.0
end-lambda: 0.7
```

Epoch 819 trained with the above config led to this PR. Use of torch.compile
decorators in nnue-pytorch model.py was found to speed up training by at least
25% on Ampere gpus when using recent pytorch compiled with cuda 12:
https://catalog.ngc.nvidia.com/orgs/nvidia/containers/pytorch

See recent main net PRs for more info on
- ranger21 and more WDL skipping: https://github.com/official-stockfish/Stockfish/pull/4942
- increasing loss when Q is too high: https://github.com/official-stockfish/Stockfish/pull/4972

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

Passed STC:
https://tests.stockfishchess.org/tests/view/65cd76151d8e83c78bfd2f52
LLR: 2.98 (-2.94,2.94) <0.00,2.00>
Total: 78336 W: 20504 L: 20115 D: 37717
Ptnml(0-2): 317, 9225, 19721, 9562, 343

Passed LTC:
https://tests.stockfishchess.org/tests/view/65ce5be61d8e83c78bfd43e9
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 41016 W: 10492 L: 10159 D: 20365
Ptnml(0-2): 22, 4533, 11071, 4854, 28

closes https://github.com/official-stockfish/Stockfish/pull/5056

Bench: 1351997
 2024-02-17 17:11:46 +01:00
cj5716
f3df0cfb84 Simplify TT PV reduction 
This also removes some incorrect fail-high logic.

Passed STC:
https://tests.stockfishchess.org/tests/view/65cb3b641d8e83c78bfd04a9
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 87968 W: 22634 L: 22468 D: 42866
Ptnml(0-2): 315, 10436, 22323, 10588, 322

Passed LTC:
https://tests.stockfishchess.org/tests/view/65cccee21d8e83c78bfd222c
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 70794 W: 17846 L: 17672 D: 35276
Ptnml(0-2): 44, 7980, 19189, 8126, 58

closes https://github.com/official-stockfish/Stockfish/pull/5055

Bench: 1474424
 2024-02-17 17:10:13 +01:00
Gahtan Nahdi
9d61822b5d Remove penalty for quiet ttMove that fails low 
Passed STC non-reg:
https://tests.stockfishchess.org/tests/view/65c691a7c865510db0286e6e
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 234336 W: 60258 L: 60255 D: 113823
Ptnml(0-2): 966, 28141, 58918, 28210, 933

Passed LTC non-reg:
https://tests.stockfishchess.org/tests/view/65c8d0d31d8e83c78bfcd4a6
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 235206 W: 59134 L: 59132 D: 116940
Ptnml(0-2): 135, 26908, 63517, 26906, 137

https://github.com/official-stockfish/Stockfish/pull/5054

Bench: 1287996
 2024-02-17 17:08:01 +01:00
Disservin
bf2c7306ac Use node counting to early stop search 
This introduces a form of node counting which can
be used to further tweak the usage of our search
time.
The current approach stops the search when almost
all nodes are searched on a single move.

The idea originally came from Koivisto, but the
implemention is a bit different, Koivisto scales
the optimal time by the nodes effort and then
determines if the search should be stopped.
We just scale down the `totalTime` and stop the
search if we exceed it and the effort is large
enough.

Passed STC:
https://tests.stockfishchess.org/tests/view/65c8e0661d8e83c78bfcd5ec
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 88672 W: 22907 L: 22512 D: 43253
Ptnml(0-2): 310, 10163, 23041, 10466, 356

Passed LTC:
https://tests.stockfishchess.org/tests/view/65ca632b1d8e83c78bfcf554
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 170856 W: 42910 L: 42320 D: 85626
Ptnml(0-2): 104, 18337, 47960, 18919, 108

closes https://github.com/official-stockfish/Stockfish/pull/5053

Bench: 1198939
 2024-02-14 21:39:31 +01:00
Tierynn Byrnes
f4f0b32d55 Refactor timeman.cpp 
Move optExtra, optConstant and maxConstant into lower scope.

closes https://github.com/official-stockfish/Stockfish/pull/5052

No functional change
 2024-02-14 21:38:17 +01:00
Muzhen Gaming
5c03883107 VVLTC search tune 
Search parameters were tuned using 16k games at
VVLTC. They were tuned starting with the new
parameters (in search only) of PR #5039.

Passed VVLTC:
https://tests.stockfishchess.org/tests/view/65c8a8fc1d8e83c78bfcd163
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 20826 W: 5355 L: 5100 D: 10371
Ptnml(0-2): 1, 1941, 6275, 2194, 2

Passed 2nd VVLTC:
https://tests.stockfishchess.org/tests/view/65cadc2d1d8e83c78bfcfdaf
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 17710 W: 4611 L: 4352 D: 8747
Ptnml(0-2): 1, 1586, 5422, 1845, 1

STC Elo estimate:
https://tests.stockfishchess.org/tests/view/65cb6aed1d8e83c78bfd0802
Elo: -1.46 ± 1.8 (95%) LOS: 5.5%
Total: 40000 W: 10267 L: 10435 D: 19298
Ptnml(0-2): 200, 4860, 10023, 4742, 175
nElo: -2.77 ± 3.4 (95%) PairsRatio: 0.97

Bench: 1198939
 2024-02-14 21:27:55 +01:00
Disservin
7ccde25baf Format code using clang-format 
No functional change
 2024-02-11 20:13:19 +01:00
Gahtan Nahdi
c115e5171e Remove quiet tt move extensions 
Passed STC:
https://tests.stockfishchess.org/tests/view/65c6934cc865510db0286e90
LLR: 2.99 (-2.94,2.94) <-1.75,0.25>
Total: 54016 W: 14065 L: 13854 D: 26097
Ptnml(0-2): 231, 6381, 13581, 6576, 239

Passed LTC:
https://tests.stockfishchess.org/tests/view/65c72b91c865510db0287a1a
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 55098 W: 13850 L: 13658 D: 27590
Ptnml(0-2): 37, 6257, 14777, 6433, 45

closes https://github.com/official-stockfish/Stockfish/pull/5049

Bench: 1027182
 2024-02-11 19:58:35 +01:00
mstembera
531747ee78 Improve thread voting inefficiencies 
Initialize the unordered map to a reasonable
number of buckets and make the move hashes well
distributed. For more see
https://github.com/official-stockfish/Stockfish/pull/4958#issuecomment-1937351190
Also make bestThreadPV and newThreadPV references
so we don't copy entire vectors.

closes https://github.com/official-stockfish/Stockfish/pull/5048

No functional change
 2024-02-11 19:55:26 +01:00
Michael Chaly
91a4cea437 Adjust best value in main search depending on depth 
This patch does similar thing to how it's done for
qsearch - in case of fail high adjust result to
lower value. Difference is that it is done only
for non-pv nodes and it's depth dependent - so
lower depth entries will have bigger adjustment
and higher depth entries will have smaller
adjustment.

Passed STC:
https://tests.stockfishchess.org/tests/view/65c3c0cbc865510db0283b21
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 112032 W: 29142 L: 28705 D: 54185
Ptnml(0-2): 479, 13152, 28326, 13571, 488

Passed LTC:
https://tests.stockfishchess.org/tests/view/65c52e62c865510db02855d5
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 132480 W: 33457 L: 32936 D: 66087
Ptnml(0-2): 67, 14697, 36222, 15156, 98

closes https://github.com/official-stockfish/Stockfish/pull/5047

Bench: 1168241
 2024-02-11 19:53:45 +01:00
Disservin
9068fdc57b Assorted cleanups 
Assorted cleanups

closes https://github.com/official-stockfish/Stockfish/pull/5046

No functional change

Co-Authored-By: Shahin M. Shahin <41402573+peregrineshahin@users.noreply.github.com>
Co-Authored-By: cj5716 <125858804+cj5716@users.noreply.github.com>
 2024-02-11 19:52:00 +01:00
GoldenRare
3d5b16df7c Remove unnecessary assignments related to adjusted static evaluation 
In both search and qsearch, there are instances
where we do unadjustedStaticEval = ss->staticEval
= eval/bestValue = tte->eval(), but immediately
after re-assign ss-static and eval/bestValue to
some new value, which makes the initial assignment
redundant.

closes https://github.com/official-stockfish/Stockfish/pull/5045

No functional change
 2024-02-11 19:46:55 +01:00
mstembera
9699f4f79a Fix the alignment of the transformer buffer 
Fixes the issue mentioned in
584d9efedc (r138417600).
Thanks to @cj5716 and @peregrineshahin for
spotting this!

closes https://github.com/official-stockfish/Stockfish/pull/5042

No functional change
 2024-02-09 19:06:25 +01:00
Muzhen Gaming
96837bc439 Remove check extension 
Passed simplification STC:
https://tests.stockfishchess.org/tests/view/65c38d2ac865510db02836cf
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 52288 W: 13578 L: 13371 D: 25339
Ptnml(0-2): 197, 6171, 13265, 6250, 261

Passed simplification LTC:
https://tests.stockfishchess.org/tests/view/65c4470ec865510db0284473
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 44958 W: 11255 L: 11055 D: 22648
Ptnml(0-2): 37, 4962, 12274, 5176, 30

closes https://github.com/official-stockfish/Stockfish/pull/5041

Bench: 1116591
 2024-02-09 19:06:25 +01:00
gahtan-syarif
15093d43c4 Simplify opponent movecount reduction 
This removes the reduction decrease that occured
when the previous ply had a movecount greater than
7.

Passed STC:
https://tests.stockfishchess.org/tests/view/65c3f6dac865510db0283ef6
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 11968 W: 3205 L: 2953 D: 5810
Ptnml(0-2): 38, 1310, 3064, 1506, 66

Passed LTC:
https://tests.stockfishchess.org/tests/view/65c42377c865510db0284217
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 35676 W: 9113 L: 8905 D: 17658
Ptnml(0-2): 22, 3893, 9802, 4097, 24

closes https://github.com/official-stockfish/Stockfish/pull/5040

Bench: 1148379
 2024-02-09 19:06:25 +01:00
cj5716
c0107b3c27 Remove simple eval 
With the recent introduction of the dual NNUE, the
need for simple eval is no longer there.

Passed STC:
https://tests.stockfishchess.org/tests/view/65c1f735c865510db0281652
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 85312 W: 22009 L: 21837 D: 41466
Ptnml(0-2): 334, 10155, 21567, 10205, 395

Passed LTC:
https://tests.stockfishchess.org/tests/view/65c2d64bc865510db0282810
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 49956 W: 12596 L: 12402 D: 24958
Ptnml(0-2): 28, 5553, 13624, 5743, 30

closes https://github.com/official-stockfish/Stockfish/pull/5037

Bench 1213676
 2024-02-09 19:06:25 +01:00
Stefan Geschwentner
f2984471c9 Tweak capture scoring for move ordering 
Move divisor from capture scoring to good capture
check and sligthly increase it.

This has several effects:
- its a speedup because for quience and probcut
  search the division now never happens. For main
  search its delayed and can be avoided if a good
  capture triggers a cutoff
- through the higher resolution of scores we have
  a more granular sorting

STC: https://tests.stockfishchess.org/tests/view/65bf2a93c865510db027dc27
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 470016 W: 122150 L: 121173 D: 226693
Ptnml(0-2): 2133, 55705, 118374, 56644, 2152

LTC: https://tests.stockfishchess.org/tests/view/65c1d16dc865510db0281339
LLR: 2.96 (-2.94,2.94) <0.50,2.50>
Total: 98988 W: 25121 L: 24667 D: 49200
Ptnml(0-2): 77, 10998, 26884, 11464, 71

closes https://github.com/official-stockfish/Stockfish/pull/5036

Bench: 1233867
 2024-02-09 19:06:25 +01:00
FauziAkram
59691d46a1 Assorted trivial cleanups 
Renaming doubleExtensions variable to multiExtensions, since now we have also triple extensions.

Some extra cleanups.

Recent tests used to measure the elo worth:
https://tests.stockfishchess.org/tests/view/659fd0c379aa8af82b96abc3
https://tests.stockfishchess.org/tests/view/65a8f3da79aa8af82b9751e3
https://tests.stockfishchess.org/tests/view/65b51824c865510db0272740
https://tests.stockfishchess.org/tests/view/65b58fbfc865510db0272f5b

closes https://github.com/official-stockfish/Stockfish/pull/5032

No functional change
 2024-02-09 19:06:24 +01:00
Muzhen Gaming
ededadcd6f VVLTC search tune 
Search parameters were tuned at 60+0.6 8-thread.
Link to the tuning attempt: https://tests.stockfishchess.org/tests/view/65b84e8dc865510db0276030

The most significant change is the triple extension parameter, from 200 to 78. This presumably improves scaling.
Additionally, the value < singularBeta - 2 condition for double extensions was removed.
This can simply be considered a parameter tweak from 2 to 0.

Passed VVLTC: https://tests.stockfishchess.org/tests/view/65baec69c865510db0278f19
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 26136 W: 6564 L: 6305 D: 13267
Ptnml(0-2): 2, 2413, 7977, 2676, 0

Passed VVLTC vs passed PR #5027: https://tests.stockfishchess.org/tests/view/65bc2adfc865510db027a561
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 52968 W: 13372 L: 13046 D: 26550
Ptnml(0-2): 4, 4944, 16265, 5264, 7

STC Elo estimate: https://tests.stockfishchess.org/tests/view/65be5514c865510db027cbc5

closes https://github.com/official-stockfish/Stockfish/pull/5029

Bench: 1478189
 2024-02-03 17:40:07 +01:00
gab8192
e815227c30 Simplify LMR condition 
Apply LMR on captures the same way it is applied on quiets

Passed Non-Reg STC:
https://tests.stockfishchess.org/tests/view/65bbf39bc865510db027a14a
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 77152 W: 19970 L: 19791 D: 37391
Ptnml(0-2): 304, 9159, 19496, 9288, 329

Passed Non-Reg LTC:
https://tests.stockfishchess.org/tests/view/65bc8889c865510db027ac9e
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 103230 W: 25997 L: 25858 D: 51375
Ptnml(0-2): 71, 11687, 27958, 11830, 69

Hit rate of removed condition (!ss->ttPv || !capture || (cutNode && (ss - 1)->moveCount > 1))
Total 1253801 Hits 1228904 Hit Rate (%) 98.0143

Hit rate of previous LMR (depth >= 2 && moveCount > 1 + rootNode && ...)
Total 1253801 Hits 727234 Hit Rate (%) 58.0023

Hit rate of simplified LMR (depth >= 2 && moveCount > 1 + rootNode)
Total 1201839 Hits 713540 Hit Rate (%) 59.3707

closes https://github.com/official-stockfish/Stockfish/pull/5028

Bench: 1438224
 2024-02-03 17:30:41 +01:00
Viren6
f2b6b5cfc9 Introduce Triple Extensions 
This replaces singularquietLMR with triple instead of double extending non-capture ttmoves that have value far below singularBeta. This threshold value is initially set to 200, there is scope for more scaling by reducing it as occured with double extensions.

Passed STC:
https://tests.stockfishchess.org/tests/view/65b683b8c865510db0274074
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 222912 W: 58141 L: 57535 D: 107236
Ptnml(0-2): 1063, 26244, 56154, 27014, 981

Passed LTC:
https://tests.stockfishchess.org/tests/view/65bae6d4c865510db0278eb5
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 66306 W: 16825 L: 16440 D: 33041
Ptnml(0-2): 40, 7374, 17952, 7735, 52

closes https://github.com/official-stockfish/Stockfish/pull/5027

bench 1394701
 2024-02-03 17:26:42 +01:00
FauziAkram
56b342f9b2 Simplify the extension formula 
Simplify the extension formula in the case of cutNode by removing the depth condition and always setting extension to -2.

Passed STC:
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 277280 W: 70760 L: 70802 D: 135718
Ptnml(0-2): 971, 31775, 73153, 31807, 934
https://tests.stockfishchess.org/tests/view/65ad08f779aa8af82b979dd6

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 452976 W: 112992 L: 113215 D: 226769
Ptnml(0-2): 266, 51041, 124112, 50788, 281
https://tests.stockfishchess.org/tests/view/65ae466fc865510db026a760

closes https://github.com/official-stockfish/Stockfish/pull/5021

Bench: 1492957
 2024-02-03 17:09:05 +01:00
Disservin
16afec0582 Refactor pv printing 
Also fix the case which is currently printing depth 0.

fixes #5019
closes https://github.com/official-stockfish/Stockfish/pull/5020

No functional change
 2024-02-03 16:50:31 +01:00
Disservin
13eb023fc0 Simplify array initializations 
also retire a few std::memset calls.

Passed non-regresion STC:
https://tests.stockfishchess.org/tests/view/65b8e162c865510db0276901
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 97504 W: 25294 L: 25140 D: 47070
Ptnml(1-2): 378, 11102, 25667, 11198, 407

closes https://github.com/official-stockfish/Stockfish/pull/5018

No functional change
 2024-02-03 16:43:23 +01:00
Viren6
fcbb02ffde Use ttPv in depth condition of singular extensions 
This replaces the PvNode condition and tte Pv call previously with using
the precomputed ttPv, and also removes the multiplier of 2.  This new
depth condition occurs with approximately equal frequency (47%) to the
old depth condition (measured when the other conditions in the if are
true), so non-linear scaling behaviour isn't expected.

Passed Non-Reg STC:
https://tests.stockfishchess.org/tests/view/65b0e132c865510db026da27
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 243232 W: 62432 L: 62437 D: 118363
Ptnml(0-2): 910, 28937, 61900, 28986, 883

Passed Non-Reg LTC:
https://tests.stockfishchess.org/tests/view/65b2053bc865510db026eea1
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 190596 W: 47666 L: 47618 D: 95312
Ptnml(0-2): 115, 21710, 51596, 21766, 111

closes https://github.com/official-stockfish/Stockfish/pull/5015

Bench: 1492957
 2024-01-26 21:15:07 +01:00
Ahmed Kerimov
c17ec9524d Move OnChange callback in Option ctors 
Parameter 'f' is passed by value and only copied once. Moving it to
avoid unnecessary copies.

closes https://github.com/official-stockfish/Stockfish/pull/5014

No functional change
 2024-01-26 21:00:41 +01:00
Michael Chaly
37bd1e774e Do more double extensions 
Parameter tweak from Black Marlin chess engine. Choose a significantly
lower value that triggers in 95% of cases, compared to the usual 84% in
standard benchmark runs.

Since the introduction by
33a858eaa1
this constant has only decreased in value over time.
2-16-17-18-21-22-25-26-52-71-75-93-140

Failed STC really fast:
https://tests.stockfishchess.org/tests/view/65b11d05c865510db026df7b
LLR: -2.94 (-2.94,2.94) <0.00,2.00>
Total: 13216 W: 3242 L: 3485 D: 6489
Ptnml(0-2): 50, 1682, 3371, 1471, 34

Was reasonable at LTC:

https://tests.stockfishchess.org/tests/view/65b13e20c865510db026e210
Elo: 1.18 ± 1.5 (95%) LOS: 94.3%
Total: 50000 W: 12517 L: 12347 D: 25136
Ptnml(0-2): 31, 5598, 13579, 5754, 38
nElo: 2.45 ± 3.0 (95%) PairsRatio: 1.03

Passed VLTC with STC bounds:
https://tests.stockfishchess.org/tests/view/65b18870c865510db026e769
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 30456 W: 7726 L: 7448 D: 15282
Ptnml(0-2): 6, 3111, 8717, 3387, 7

Passed VVLTC with LTC bounds:
https://tests.stockfishchess.org/tests/view/65b20b95c865510db026eef0
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 36134 W: 9158 L: 8859 D: 18117
Ptnml(0-2): 3, 3455, 10850, 3758, 1

closes https://github.com/official-stockfish/Stockfish/pull/5013

Bench: 1503692
 2024-01-26 20:55:16 +01:00
Disservin
1dfbde2d10 Move perft out of search 
This splits the logic of search and perft. Before, threads were started,
which then constructed a search object, which then started perft and
returned immediately. All of this is unnecessary, instead uci should
start perft right away.

closes https://github.com/official-stockfish/Stockfish/pull/5008

No functional change
 2024-01-26 20:52:26 +01:00
FauziAkram
3d49a99aaf Refactor history score calculation 
Passed STC:
https://tests.stockfishchess.org/tests/view/65ad08b179aa8af82b979dd1
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 161376 W: 41582 L: 41498 D: 78296
Ptnml(0-2): 633, 19354, 40611, 19476, 614

Passed LTC:
https://tests.stockfishchess.org/tests/view/65af966fc865510db026c0f0
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 116526 W: 29269 L: 29143 D: 58114
Ptnml(0-2): 71, 13252, 31509, 13342, 89

closes https://github.com/official-stockfish/Stockfish/pull/5006

Bench: 1317504
 2024-01-26 20:44:16 +01:00
FauziAkram
2b62c4452d Remove redundant max operation on lmrDepth 
Removed a restriction that prohibited history heuristics sum in futility
pruning to exceed some negative value.

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 279040 W: 71095 L: 71143 D: 136802
Ptnml(0-2): 949, 33574, 70474, 33622, 901
https://tests.stockfishchess.org/tests/view/65aaef4c79aa8af82b977631

Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 75156 W: 18884 L: 18715 D: 37557
Ptnml(0-2): 52, 8445, 20408, 8628, 45
https://tests.stockfishchess.org/tests/view/65ae7ef3c865510db026abf5

closes https://github.com/official-stockfish/Stockfish/pull/5004

Bench: 1566543
 2024-01-26 20:40:22 +01:00
Muzhen Gaming
a6fd17f27d VLTC search tune 
Search parameters were tuned using 152k games at 180+1.8.

Passed VLTC:
https://tests.stockfishchess.org/tests/view/65a7a81979aa8af82b973a20
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 117338 W: 29244 L: 28848 D: 59246
Ptnml(0-2): 24, 12474, 33267, 12890, 14

Passed VVLTC:
https://tests.stockfishchess.org/tests/view/65ab246679aa8af82b977982
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 28164 W: 7239 L: 6957 D: 13968
Ptnml(0-2): 3, 2651, 8490, 2937, 1

STC Elo estimate:
https://tests.stockfishchess.org/tests/view/65ac7c0979aa8af82b9792a6
Elo: -0.53 ± 2.0 (95%) LOS: 30.4%
Total: 30000 W: 7688 L: 7734 D: 14578
Ptnml(0-2): 102, 3617, 7614, 3559, 108
nElo: -1.03 ± 3.9 (95%) PairsRatio: 0.99

closes https://github.com/official-stockfish/Stockfish/pull/5003

Bench: 1235377
 2024-01-21 12:49:30 +01:00
Robert Nurnberg @ elitebook
a901474bf9 Update the WDL model 
Update the internal WDL model. After the dual net merge, the internal
evaluations have drifted upwards a bit. With this PR
`NormalizeToPawnValue` changes from `328` to `345`.

The new model was fitted based on about 200M positions extracted from
3.4M fishtest LTC games from the last two weeks, involving SF versions
from 6deb88728f to current master.

Apart from the WDL model parameter update, this PR implements the
following changes:

WDL Model:
- an incorrect 8-move shift in master's WDL model has been fixed
- the polynomials `p_a` and `p_b` are fitted over the move range [8, 120]
- the coefficients for `p_a` and `p_b` are optimized by maximizing the
  probability of predicting the observed outcome (credits to @vondele)

SF code:
- for wdl values, move will be clamped to `max(8, min(120, move))`
- no longer clamp the internal eval to [-4000,4000]
- compute `NormalizeToPawnValue` with `round`, not `trunc`

The PR only affects displayed `cp` and `wdl` values.

closes https://github.com/official-stockfish/Stockfish/pull/5002

No functional change
 2024-01-21 12:45:03 +01:00
Shahin M. Shahin
ad9fcbc496 Refactor get_best_thread 
Make get_best_thread function easier to understand.

Passed non-reg SMP STC:
https://tests.stockfishchess.org/tests/view/65a91c6679aa8af82b975500
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 186000 W: 46379 L: 46325 D: 93296
Ptnml(0-2): 269, 21374, 49634, 21480, 243

closes https://github.com/official-stockfish/Stockfish/pull/5001

No functional change
 2024-01-21 12:42:28 +01:00
rn5f107s2
e860f620aa Reduce futility_margin further when improving 
The idea of this is to unroll the futility_margin calculation to allow
for the improving flag to have a greater effect on the futility margin.
The current factor is 1.5 instead of the previous 1 resulting in a
deduction of an extra margin/2 from futilit_margin if improving. The
chosen value was not tuned, meaning that there is room for tweaking it.
This patch is partially inspired by @Vizvezdenec, who, although quite
different in execution, tested another idea where the futility_margin is
lowered further when improving [1].

[1]: (first take) https://tests.stockfishchess.org/tests/view/65a56b1879aa8af82b97164b

Passed STC:
https://tests.stockfishchess.org/tests/live_elo/65a8bfc179aa8af82b974e3c
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 161152 W: 41321 L: 40816 D: 79015
Ptnml(0-2): 559, 19030, 40921, 19479, 587

Passed rebased LTC:
https://tests.stockfishchess.org/tests/live_elo/65a8b9ef79aa8af82b974dc0
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 96024 W: 24172 L: 23728 D: 48124
Ptnml(0-2): 56, 10598, 26275, 11012, 71

closes https://github.com/official-stockfish/Stockfish/pull/5000

Bench: 1281703
 2024-01-21 12:42:07 +01:00
Viren6
aa15a9179b Refactor ttPv reduction conditions 
closes https://github.com/official-stockfish/Stockfish/pull/4999

No functional change
 2024-01-21 12:33:08 +01:00
Disservin
856e60d12f Refactor NativeThread start_routine 
Removes the free function and fixes the formatting for the function
call.

closes https://github.com/official-stockfish/Stockfish/pull/4995

No functional change
 2024-01-21 12:21:01 +01:00
Viren6
c8bc2ce4fa Improve ttPv reduction 
This patch allows a partial reduction decrease when a node is likely to
fail low, and increases the reduction decrease when a node has failed
high.

Passed STC:
https://tests.stockfishchess.org/tests/view/65a626e779aa8af82b9722bc
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 157824 W: 40332 L: 39835 D: 77657
Ptnml(0-2): 543, 18617, 40098, 19108, 546

Passed LTC:
https://tests.stockfishchess.org/tests/view/65a7290279aa8af82b97328a
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 57228 W: 14475 L: 14111 D: 28642
Ptnml(0-2): 34, 6278, 15633, 6628, 41

closes https://github.com/official-stockfish/Stockfish/pull/4994

Bench: 1364759
 2024-01-17 18:56:37 +01:00
FauziAkram
9a9702d668 Remove threatenedByPawn from rook threat 
Can be simplified away.

Passed STC:
https://tests.stockfishchess.org/tests/view/65a3fa4179aa8af82b96face
LLR: 2.92 (-2.94,2.94) <-1.75,0.25>
Total: 30592 W: 7903 L: 7674 D: 15015
Ptnml(0-2): 96, 3590, 7711, 3787, 112

Passed LTC:
https://tests.stockfishchess.org/tests/view/65a42b9a79aa8af82b96fe88
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 73656 W: 18382 L: 18212 D: 37062
Ptnml(0-2): 47, 8287, 19981, 8475, 38

closes https://github.com/official-stockfish/Stockfish/pull/4993

Bench: 1430061
 2024-01-17 18:55:44 +01:00
pb00067
0fbad56c50 Refactor code for correcting unadjustedStaticEval 
Passed non-regression STC:
https://tests.stockfishchess.org/tests/live_elo/65a4df6a79aa8af82b970ca0
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 43328 W: 11103 L: 10892 D: 21333
Ptnml(0-2): 120, 4920, 11407, 5063, 154

https://github.com/official-stockfish/Stockfish/pull/4992

No functional change
 2024-01-17 18:51:03 +01:00