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
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: Sun Apr 28 21:43:46 2024 +0200
Timestamp: 1714333426

Simplify non-pawn material divisor to a constant

Passed STC:
https://tests.stockfishchess.org/tests/view/662942603fe04ce4cefc7aba
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 272832 W: 70456 L: 70497 D: 131879 Elo -0.05
Ptnml(0-2): 1020, 32619, 69154, 32628, 995

Passed LTC:
https://tests.stockfishchess.org/tests/view/662dfe3b6115ff6764c829eb
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 100254 W: 25446 L: 25303 D: 49505 Elo +0.50
Ptnml(0-2): 121, 11292, 27166, 11419, 129

closes https://github.com/official-stockfish/Stockfish/pull/5198

Bench: 1544645
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: cj5716
Date: Sun Apr 28 21:36:34 2024 +0200
Timestamp: 1714332994

Penalise the TT move in multicut

Passed STC:
LLR: 2.99 (-2.94,2.94) <0.00,2.00>
Total: 185504 W: 48079 L: 47533 D: 89892 Elo +1.02
Ptnml(0-2): 716, 21866, 46988, 22520, 662
https://tests.stockfishchess.org/tests/view/662d9e1d6115ff6764c7f83d

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 75612 W: 19351 L: 18948 D: 37313 Elo +1.85
Ptnml(0-2): 46, 8363, 20592, 8752, 53
https://tests.stockfishchess.org/tests/view/662dc9dc6115ff6764c80fea

closes https://github.com/official-stockfish/Stockfish/pull/5195

Bench: 1415435
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: mstembera
Date: Sun Apr 28 21:35:48 2024 +0200
Timestamp: 1714332948

Combine remove and add in update_accumulator_refresh_cache()

Combine remove and add in update_accumulator_refresh_cache().
Move remove before add to match other parts of the code.

STC:
https://tests.stockfishchess.org/tests/view/662d96dc6115ff6764c7f4ca
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 364032 W: 94421 L: 93624 D: 175987 Elo +0.76
Ptnml(0-2): 1261, 41983, 94811, 42620, 1341

closes https://github.com/official-stockfish/Stockfish/pull/5194

Bench: 1836777
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: mstembera
Date: Sun Apr 28 21:30:19 2024 +0200
Timestamp: 1714332619

Cache small net w/ psqtOnly support

Caching the small net in the same way as the big net allows them to
share the same code path and completely removes
update_accumulator_refresh().

STC:
https://tests.stockfishchess.org/tests/view/662bfb5ed46f72253dcfed85
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 151712 W: 39252 L: 39158 D: 73302 Elo +0.22
Ptnml(0-2): 565, 17474, 39683, 17570, 564

closes https://github.com/official-stockfish/Stockfish/pull/5194

Bench: 1836777
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: Joost VandeVondele
Date: Sun Apr 28 21:27:28 2024 +0200
Timestamp: 1714332448

Output some basic info about the used networks

Adds size in memory as well as layer sizes as in

info string NNUE evaluation using nn-ae6a388e4a1a.nnue (132MiB, (22528, 3072, 15, 32, 1))
info string NNUE evaluation using nn-baff1ede1f90.nnue (6MiB, (22528, 128, 15, 32, 1))

For example, the size in MiB is useful to keep the fishtest memory sizes up-to-date,
the L1-L3 sizes give a useful hint about the architecture used.

closes https://github.com/official-stockfish/Stockfish/pull/5193

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: Disservin
Date: Sun Apr 28 21:26:36 2024 +0200
Timestamp: 1714332396

Fix missing initialization of AccumulatorCaches in Eval::trace

Add a constructor to `AccumulatorCaches` instead of just calling
`clear(networks)` to prevent similar issues from appearing in the
future.

fixes https://github.com/official-stockfish/Stockfish/issues/5190

closes https://github.com/official-stockfish/Stockfish/pull/5191

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: xoto10
Date: Sun Apr 28 21:26:25 2024 +0200
Timestamp: 1714332385

Use less time on recaptures

Credit for the idea goes to peregrine on discord.

Passed STC 10+0.1:
https://tests.stockfishchess.org/tests/view/662652623fe04ce4cefc48cf
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 75712 W: 19793 L: 19423 D: 36496 Elo +1.70
Ptnml(0-2): 258, 8487, 20023, 8803, 285

Passed LTC 60+0.6:
https://tests.stockfishchess.org/tests/view/6627495e3fe04ce4cefc59b6
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 49788 W: 12743 L: 12404 D: 24641 Elo +2.37
Ptnml(0-2): 29, 5141, 14215, 5480, 29

The code was updated slightly and tested for non-regression against the
original code at STC:

LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 41952 W: 10912 L: 10698 D: 20342 Elo +1.77
Ptnml(0-2): 133, 4825, 10835, 5061, 122
https://tests.stockfishchess.org/tests/view/662d84f56115ff6764c7e438

closes https://github.com/official-stockfish/Stockfish/pull/5189

Bench: 1836777
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: gab8192
Date: Wed Apr 24 18:38:20 2024 +0200
Timestamp: 1713976700

Implement accumulator refresh table

For each thread persist an accumulator cache for the network, where each
cache contains multiple entries for each of the possible king squares.
When the accumulator needs to be refreshed, the cached entry is used to more
efficiently update the accumulator, instead of rebuilding it from scratch.
This idea, was first described by Luecx (author of Koivisto) and
is commonly referred to as "Finny Tables".

When the accumulator needs to be refreshed, instead of filling it with
biases and adding every piece from scratch, we...

1. Take the `AccumulatorRefreshEntry` associated with the new king bucket
2. Calculate the features to activate and deactivate (from differences
between bitboards in the entry and bitboards of the actual position)
3. Apply the updates on the refresh entry
4. Copy the content of the refresh entry accumulator to the accumulator
we were refreshing
5. Copy the bitboards from the position to the refresh entry, to match
the newly updated accumulator

Results at STC:
https://tests.stockfishchess.org/tests/view/662301573fe04ce4cefc1386
(first version)
https://tests.stockfishchess.org/tests/view/6627fa063fe04ce4cefc6560
(final)

Non-Regression between first and final:
https://tests.stockfishchess.org/tests/view/662801e33fe04ce4cefc660a

STC SMP:
https://tests.stockfishchess.org/tests/view/662808133fe04ce4cefc667c

closes https://github.com/official-stockfish/Stockfish/pull/5183

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: Wed Apr 24 18:24:01 2024 +0200
Timestamp: 1713975841

Tune Search Parameters

Parameters Tune, adding also another tunable parameter (npmDiv) to be
variable for different nets (bignet, smallnet, psqtOnly smallnet). P.s:
The changed values are only the parameters where there is agreement
among the different time controls, so in other words, the tunings are
telling us that changing these specific values to this specific
direction is good in all time controls, so there shouldn't be a high
risk of regressing at longer time controls.

Passed STC:
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 39552 W: 10329 L: 9999 D: 19224 Elo +2.90
Ptnml(0-2): 156, 4592, 9989, 4844, 195
https://tests.stockfishchess.org/tests/view/661be9a0bd68065432a088c0

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 56394 W: 14439 L: 14078 D: 27877 Elo +2.22
Ptnml(0-2): 30, 6152, 15480, 6497, 38
https://tests.stockfishchess.org/tests/view/661c746296961e72eb565406

closes https://github.com/official-stockfish/Stockfish/pull/5187

Bench: 1836777
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: Disservin
Date: Wed Apr 24 18:20:55 2024 +0200
Timestamp: 1713975655

Restore NPS output for Perft

Previously it was possible to also get the node counter after running a bench with perft, i.e.
`./stockfish bench 1 1 5 current perft`, caused by a small regression from the uci refactoring.

```
Nodes searched: 4865609

===========================
Total time (ms) : 18
Nodes searched : 4865609
Nodes/second : 270311611
````

closes https://github.com/official-stockfish/Stockfish/pull/5188

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: cj5716
Date: Sun Apr 21 14:50:04 2024 +0200
Timestamp: 1713703804

Tweak TT aging and replacement strategies

We change the definition of "age" from "age of this position" to "age of this TT entry".
In this way, despite being on the same position, when we save into TT, we always prefer the new entry as compared to the old one.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 152256 W: 39597 L: 39110 D: 73549 Elo +1.11
Ptnml(0-2): 556, 17562, 39398, 18063, 549
https://tests.stockfishchess.org/tests/view/6620faee3fe04ce4cefbf215

Passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 51564 W: 13242 L: 12895 D: 25427 Elo +2.34
Ptnml(0-2): 24, 5464, 14463, 5803, 28
https://tests.stockfishchess.org/tests/view/66231ab53fe04ce4cefc153e

closes #5184

Bench 1479416
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: Disservin
Date: Sun Apr 21 14:49:11 2024 +0200
Timestamp: 1713703751

Move ALSR change to CI Workflow file

It makes more sense to not (potentially) change the developers alsr entropy setting to make the test run through. This should be an active choice even if the test then might fail locally for them.

closes https://github.com/official-stockfish/Stockfish/pull/5182

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: Joost VandeVondele
Date: Sun Apr 21 14:46:01 2024 +0200
Timestamp: 1713703561

Improve CI

the recent refactoring has shown some limitations of our testing, hence we add a couple of more tests including:
* expected mate score
* expected mated score
* expected in TB win score
* expected in TB loss score
* expected info line output
* expected info line output (wdl)

closes https://github.com/official-stockfish/Stockfish/pull/5181

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: Robert Nurnberg @ elitebook
Date: Sun Apr 21 14:40:02 2024 +0200
Timestamp: 1713703202

update the WDL model

The patch only changes the displayed cp and wdl values.

closes https://github.com/official-stockfish/Stockfish/pull/5178

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: Gahtan Nahdi
Date: Sun Apr 21 14:38:16 2024 +0200
Timestamp: 1713703096

fix clang compiler warning for avx512 build

Initialize variable in constexpr function to get rid of clang compiler warning for avx512 build.

closes https://github.com/official-stockfish/Stockfish/pull/5176

Non-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: Michael Chaly
Date: Sun Apr 21 14:35:54 2024 +0200
Timestamp: 1713702954

Trivial cleanup

Make naming and declaration of futilityValue in search consistent between different places.

closes https://github.com/official-stockfish/Stockfish/pull/5165

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: Disservin
Date: Sun Apr 21 14:35:01 2024 +0200
Timestamp: 1713702901

Refactor elapsed time checks in search

Small improvement of the elapsed time usage in search, makes the code easier to read overall.
Also Search::Worker::iterative_deepening() now only checks the elapsed time once, instead of 3 times in a row.

Non Regression STC:
https://tests.stockfishchess.org/tests/view/6617005d5a4693796d965c3c
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 61024 W: 16002 L: 15806 D: 29216 Elo +1.12
Ptnml(0-2): 243, 6874, 16102, 7030, 263

closes https://github.com/official-stockfish/Stockfish/pull/5163

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: Disservin
Date: Sun Apr 21 14:32:26 2024 +0200
Timestamp: 1713702746

Update outdated comments

closes https://github.com/official-stockfish/Stockfish/pull/5158

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: Disservin
Date: Sat Apr 13 22:05:19 2024 +0200
Timestamp: 1713038719

Fix wrong sign for 200 TB score

Fix another case of 9032c6cbe74ccf7e8963755501e7e6cc473ae471

* TB values can have a distance of 0, mainly when we are in a tb position but haven't found mate.
* Add a missing whitespace to UCIEngine::on_update_no_moves()

Closes https://github.com/official-stockfish/Stockfish/pull/5172

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: Disservin
Date: Fri Apr 12 19:37:39 2024 +0200
Timestamp: 1712943459

Remove duplicated Position object in UCIEngine

Also fixes searchmoves.

Drop the need of a Position object in uci.cpp.

A side note, it is still required for the static functions,
but these should be moved to a different namespace/class
later on, since sf kinda relies on them.

closes https://github.com/official-stockfish/Stockfish/pull/5169

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: Shahin M. Shahin
Date: Fri Apr 12 18:11:54 2024 +0200
Timestamp: 1712938314

Fix some more UCI output

further fall-out of the refactoring, fixes:

* the position object in UCI is not never getting updated if position token is used
* duplicate string of " wdl "

See also:

https://discord.com/channels/435943710472011776/1032922913499783169/1228227522945351690
https://discord.com/channels/435943710472011776/813919248455827515/1228288106449338398

closes https://github.com/official-stockfish/Stockfish/pull/5168

No functional change

Co-Authored-By: disservin <45608332+>
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: Robert Nurnberg @ elitebook
Date: Fri Apr 12 09:30:34 2024 +0200
Timestamp: 1712907034

Fix wrong mate sign

introduced yesterday by the UCI refactoring 9032c6cbe

fixes #5166
closes https://github.com/official-stockfish/Stockfish/pull/5167

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 Apr 11 22:47:40 2024 +0200
Timestamp: 1712868460

Simplify the depth-dependent part of the best value adjustment formula in main search

Passed STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 139648 W: 36171 L: 36061 D: 67416 Elo +0.27
Ptnml(0-2): 545, 16685, 35282, 16739, 573
https://tests.stockfishchess.org/tests/view/660d953b8ff4a059828d625d

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 222894 W: 56519 L: 56505 D: 109870 Elo +0.02
Ptnml(0-2): 112, 25145, 60971, 25055, 164
https://tests.stockfishchess.org/tests/view/660fd4afbfeb43334bf7d558

closes https://github.com/official-stockfish/Stockfish/pull/5164

bench: 1479416
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: gab8192
Date: Thu Apr 11 22:43:00 2024 +0200
Timestamp: 1712868180

Remove an useless assignment

The assignment (ss + 1)->excludedMove = Move::none() can be simplified away because when that line is reached, (ss + 1)->excludedMove is always already none. The only moment stack[x]->excludedMove is modified, is during singular search, but it is reset to none right after the singular search is finished.

closes https://github.com/official-stockfish/Stockfish/pull/5153

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: Disservin
Date: Thu Apr 11 22:41:35 2024 +0200
Timestamp: 1712868095

Remove COMPILER from Makefile

The same functionality is available by using COMPCXX and having another variable which does the same is just confusing.
There was only one mention on Stockfish Wiki about this which has been changed to COMPCXX.

closes https://github.com/official-stockfish/Stockfish/pull/5154

No functional change
see source

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