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
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Sat Mar 14 16:27:54 2020 +0100
Timestamp: 1584199674

simplify castling part of generate_all.

somewhat more compact, generates same code.

close https://github.com/official-stockfish/Stockfish/pull/2580

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: silversolver1
Date: Mon Mar 9 22:46:13 2020 +0100
Timestamp: 1583790373

Remove set statScore to zero

Simplification. Removes setting statScore to zero if negative.

STC:
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 84820 W: 16100 L: 16033 D: 52687 Elo +0.27
Ptnml(0-2): 1442, 9865, 19723, 9944, 1436
https://tests.stockfishchess.org/tests/view/5e654fdae42a5c3b3ca2e2f8

LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 57658 W: 7435 L: 7391 D: 42832 Elo +0.27
Ptnml(0-2): 441, 5397, 17104, 5451, 436
https://tests.stockfishchess.org/tests/view/5e657ce9e42a5c3b3ca2e307

closes https://github.com/official-stockfish/Stockfish/pull/2578

Bench: 5168890
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Mon Mar 9 22:16:26 2020 +0100
Timestamp: 1583788586

Equations for edges and corners.

This is a functional simplification that removes the large arrays in endgames.cpp.
It also fixes a recently introduced bug (960d59d54143d84aab26deae65279a611fc989f4) in KNBvK,
now using flip_file() instead of ~.

One fen added to bench to increase endgame coverage.

STC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 174724 W: 33325 L: 33404 D: 107995 Elo -0.16
Ptnml(0-2): 2503, 19607, 43181, 19608, 2463
http://tests.stockfishchess.org/tests/view/5e6448ffe42a5c3b3ca2e287

LTC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 35640 W: 4679 L: 4621 D: 26340 Elo +0.57
Ptnml(0-2): 189, 2991, 11424, 3005, 211
http://tests.stockfishchess.org/tests/view/5e650b24e42a5c3b3ca2e2d8

closes https://github.com/official-stockfish/Stockfish/pull/2577

Bench: 5527957
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Gary Heckman
Date: Sat Mar 7 11:14:27 2020 +0100
Timestamp: 1583576067

Fix ambiguity between clamp implementations

There is an ambiguity between global and std clamp implementations when compiling in c++17,
and on certain toolchains that are not strictly conforming to c++11.
This is solved by putting our clamp implementation in a namespace.

closes https://github.com/official-stockfish/Stockfish/pull/2572

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Sat Mar 7 11:09:38 2020 +0100
Timestamp: 1583575778

Remove KRPPKRPScaleFactors array

Fucntional simplification that removes the KRPPKRPScaleFactors array.

STC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 47374 W: 9159 L: 9049 D: 29166 Elo +0.81
Ptnml(0-2): 707, 5325, 11560, 5341, 754
http://tests.stockfishchess.org/tests/view/5e5ff464e42a5c3b3ca2e156

LTC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 31268 W: 4064 L: 3995 D: 23209 Elo +0.77
Ptnml(0-2): 173, 2734, 9764, 2777, 186
http://tests.stockfishchess.org/tests/view/5e61be6ce42a5c3b3ca2e1c1

closes https://github.com/official-stockfish/Stockfish/pull/2575

Bench 5123316
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Sat Mar 7 10:55:15 2020 +0100
Timestamp: 1583574915

Cleanup KBPsK endgame

* Clarify distinction between strong side pawns and all pawns.
* Simplify and speed-up determination of pawns on the same file.
* Clarify comments.
* more_than_one() is probably faster than pos.count.

Passed STC:
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 40696 W: 7856 L: 7740 D: 25100 Elo +0.99
Ptnml(0-2): 584, 4519, 10054, 4579, 612
http://tests.stockfishchess.org/tests/view/5e6153b1e42a5c3b3ca2e1a9

closes https://github.com/official-stockfish/Stockfish/pull/2574

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Sat Mar 7 10:48:16 2020 +0100
Timestamp: 1583574496

Small speed-up in BetweenBB

A speed-up removing some comparisons.

closes https://github.com/official-stockfish/Stockfish/pull/2571

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Wed Mar 4 07:17:04 2020 +0100
Timestamp: 1583302624

Use equations for PushAway and PushClose

A functional simplification replacing the corresponding arrays. Tested in two variants,
also the simpler one performs well, even though differences to master should be minimal.

STC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 57864 W: 11092 L: 11001 D: 35771 Elo +0.55
Ptnml(0-2): 826, 6458, 14320, 6455, 873
http://tests.stockfishchess.org/tests/view/5e5da5b6e42a5c3b3ca2e05c

LTC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 7198 W: 982 L: 883 D: 5333 Elo +4.78
Ptnml(0-2): 33, 575, 2296, 650, 45
http://tests.stockfishchess.org/tests/view/5e5df13ae42a5c3b3ca2e077

LTC (This exact version. . . more simplified)
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 5392 W: 729 L: 631 D: 4032 Elo +6.32
Ptnml(0-2): 23, 405, 1751, 485, 32
http://tests.stockfishchess.org/tests/view/5e5ead99e42a5c3b3ca2e0e4

closes https://github.com/official-stockfish/Stockfish/pull/2570

Bench 5123316
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Wed Mar 4 07:11:48 2020 +0100
Timestamp: 1583302308

Consolidate Square Flipping

Add a flip_rank() and flip_file() so that all of the square flipping can be consolidated.

STC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 57234 W: 11064 L: 10969 D: 35201 Elo +0.58
Ptnml(0-2): 822, 6562, 13801, 6563, 869
http://tests.stockfishchess.org/tests/view/5e5d2f2aafe6254521f2ffaa

closes https://github.com/official-stockfish/Stockfish/pull/2568

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Joost VandeVondele
Date: Sun Mar 1 09:31:58 2020 +0100
Timestamp: 1583051518

Small cleanups

closes https://github.com/official-stockfish/Stockfish/pull/2546

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Guenther Demetz
Date: Sun Mar 1 09:20:31 2020 +0100
Timestamp: 1583050831

Simplify lowply-history logic

Don't restrict usage to ttPv nodes exclusively

STC:
http://tests.stockfishchess.org/tests/view/5e5634f284a82b4acd41499a
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 152796 W: 29146 L: 29178 D: 94472 Elo -0.07
Ptnml(0-2): 2590, 17792, 35628, 17836, 2552

LTC:
http://tests.stockfishchess.org/tests/view/5e575d4984a82b4acd4149e8
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 20078 W: 2688 L: 2587 D: 14803 Elo +1.75
Ptnml(0-2): 139, 1914, 5853, 1973, 160

closes https://github.com/official-stockfish/Stockfish/pull/2565

bench: 4923286
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Moez Jellouli
Date: Thu Feb 27 13:14:51 2020 +0100
Timestamp: 1582805691

Weak queen protection

Extra penalty if weak piece is only protected by a queen.

STC:
http://tests.stockfishchess.org/tests/view/5e53c6ab84a82b4acd4148fa
LLR: 2.96 (-2.94,2.94) {-0.50,1.50}
Total: 44630 W: 8615 L: 8359 D: 27656 Elo +1.99
Ptnml(0-2): 746, 5156, 10323, 5276, 814

LTC:
http://tests.stockfishchess.org/tests/view/5e54e05d84a82b4acd414947
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 175480 W: 23085 L: 22409 D: 129986 Elo +1.34
Ptnml(0-2): 1264, 16494, 51678, 16910, 1394

closes https://github.com/official-stockfish/Stockfish/pull/2564

Bench: 4923286
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: AndyGrant
Date: Tue Feb 25 21:10:10 2020 +0100
Timestamp: 1582661410

Fix TT write in MultiPV case.

fixes an error reported earlier as https://github.com/official-stockfish/Stockfish/issues/2404 by @AndyGrant.

MultiPV at root shouldn't write to the TT for later lines, as that is neither the eval nor the bestmove for that position.
Fixing this error doesn't matter for playing games (http://tests.stockfishchess.org/tests/view/5dcdbd810ebc590256324a11).

However, it can lead to wrong mate announcements as reported by @uriblass. In particular the following testcase gives
wrong results for the second search, prior to this patch:

```
setoption name MultiPV value 2
position fen 5R2/2kB2p1/p2bR3/8/3p1B2/8/PPP5/2K5 b - - 0 49
go depth 40
position fen 2B2R2/3r2p1/p1kbR3/8/3p1B2/8/PPP5/2K5 b - - 8 48
go depth 40
```

fixes https://github.com/official-stockfish/Stockfish/issues/2561
closes https://github.com/official-stockfish/Stockfish/pull/2562

Only affects MultiPV search.

Bench: 4697493
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: 31m059
Date: Tue Feb 25 21:03:42 2020 +0100
Timestamp: 1582661022

Use single param for Outpost and ReachableOutpost.

In November 2019, as a result of the simplification of rank-based outposts by 37698b0,
separate bonuses were introduced for outposts that are currently occupied and outposts
that are reachable on the next move. However, the values of these two bonuses are
quite similar, and they have remained that way for three months of development.

It appears that we can safely retire the separate ReachableOutpost parameter and
use the same Outpost bonus in both cases, restoring the basic principles of Stockfish
outpost evaluation to their pre-November state, while also reducing
the size of the parameter space.

STC:
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 47680 W: 9213 L: 9092 D: 29375 Elo +0.88
Ptnml(0-2): 776, 5573, 11071, 5594, 826
https://tests.stockfishchess.org/tests/view/5e51e33190a0a02810d09802

LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 14690 W: 1960 L: 1854 D: 10876 Elo +2.51
Ptnml(0-2): 93, 1381, 4317, 1435, 119
https://tests.stockfishchess.org/tests/view/5e52197990a0a02810d0980f

closes https://github.com/official-stockfish/Stockfish/pull/2559

Bench: 4697493
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Günther Demetz
Date: Sat Feb 22 21:32:32 2020 +0100
Timestamp: 1582403552

Improve move order near the root

Current move histories are known to work well near the leaves, whilst at
higher depths they aren't very helpful. To address this problem this
patch introduces a table dedicated for what's happening at plies 0-3.
It's structured like mainHistory with ply index instead of color.
It get cleared with each new search and is filled during iterative
deepening at higher depths when recording successful quiet moves near
the root or traversing nodes which were in the principal variation
(ttPv).

Medium TC (20+0.2):
https://tests.stockfishchess.org/tests/view/5e4d358790a0a02810d096dc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 100910 W: 16682 L: 16376 D: 67852 Elo +1.05
Ptnml(0-2): 1177, 10983, 25883, 11181, 1231

LTC:
https://tests.stockfishchess.org/tests/view/5e4e2cb790a0a02810d09714
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 80444 W: 10495 L: 10095 D: 59854 Elo +1.73
Ptnml(0-2): 551, 7479, 23803, 7797, 592

closes https://github.com/official-stockfish/Stockfish/pull/2557

Bench: 4705960
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Thu Feb 20 08:32:17 2020 +0100
Timestamp: 1582183937

Updated KNNKP endgame.

This is a patch that significantly improves playing KNNKP endgames:

```
Score of 2553 vs master: 132 - 38 - 830 [0.547] 1000
Elo difference: 32.8 +/- 8.7, LOS: 100.0 %, DrawRatio: 83.0 %
```

At the same time it reduces the evaluation of this mostly draw engame
from ~7.5 to ~1.5

This patch does not regress against master in normal games:

STC
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 96616 W: 18459 L: 18424 D: 59733 Elo +0.13
Ptnml(0-2): 1409, 10812, 23802, 10905, 1380
http://tests.stockfishchess.org/tests/view/5e49dfe6f8d1d52b40cd31bc

LTC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 49726 W: 6340 L: 6304 D: 37082 Elo +0.25
Ptnml(0-2): 239, 4227, 15906, 4241, 250
http://tests.stockfishchess.org/tests/view/5e4ab9ee16fb3df8c4cc01d0

Theory: KNNK is a dead draw, however the presence of the additional weakSide pawn opens up some mate opportunities. The idea is to block the pawn (preferably behind the Troitsky line) with one of the knights and press the weakSide king into a corner. If we can stalemate the king, we release the pawn with the knight (to avoid actual stalemate), and use the knight to complete the mate before the pawn promotes. This is also why there is an additional penalty for advancement of the pawn.

closes https://github.com/official-stockfish/Stockfish/pull/2553

Bench: 4981770
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: protonspring
Date: Sat Feb 15 15:13:14 2020 +0100
Timestamp: 1581775994

Simplify Futility Move Count

remove two constants

STC
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 62050 W: 11903 L: 11802 D: 38345 Elo +0.57
Ptnml(0-2): 1002, 7346, 14283, 7320, 1065
http://tests.stockfishchess.org/tests/view/5e41d73be70d848499f63c6d

LTC
LLR: 2.93 (-2.94,2.94) {-1.50,0.50}
Total: 12850 W: 1679 L: 1572 D: 9599 Elo +2.89
Ptnml(0-2): 82, 1171, 3818, 1249, 96
http://tests.stockfishchess.org/tests/view/5e42bf07e70d848499f63cc0

Bench: 4762351
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Joost VandeVondele
Date: Sat Feb 15 15:10:07 2020 +0100
Timestamp: 1581775807

Fix for incorrect VALUE_MATE_IN_MAX_PLY usage.

Fixes #2533, fixes #2543, fixes #2423.

the code that prevents false mate announcements depending on the TT
state (GHI), incorrectly used VALUE_MATE_IN_MAX_PLY. The latter
constant, however, also includes, counterintuitively, the TB win range.

This patch fixes that, by restoring the behavior for TB win scores,
while retaining the false mate correctness, and improving the mate
finding ability. In particular

no alse mates are announced with the poisened hash testcase
```
position fen 8/8/8/3k4/8/8/6K1/7R w - - 0 1
go depth 40
position fen 8/8/8/3k4/8/8/6K1/7R w - - 76 1
go depth 20
ucinewgame
```

mates are found with the testcases reported in #2543
```
position fen 4k3/3pp3/8/8/8/8/2PPP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 55
ucinewgame
```
and
```
position fen 4k3/4p3/8/8/8/8/3PP3/4K3 w - - 0 1
setoption name Hash value 1024
go depth 45
ucinewgame
```

furthermore, on the mate finding benchmark (ChestUCI_23102018.epd),
performance improves over master, roughly reaching performance with the
false mate protection reverted
```
Analyzing 6566 mate positions for best and found mates:

----------------best ---------------found
nodes master revert fixed master revert fixed
16000000 4233 4236 4235 5200 5201 5199
32000000 4583 4585 4585 5417 5424 5418
64000000 4852 4853 4855 5575 5584 5579
128000000 5071 5068 5066 5710 5720 5716
256000000 5280 5282 5279 5819 5827 5826
512000000 5471 5468 5468 5919 5935 5932
```

On a testcase with TB enabled, progress is made consistently, contrary
to master
```
setoption name SyzygyPath value ../../../syzygy/3-4-5/
setoption name Hash value 2048
position fen 1R6/3k4/8/K2p4/4n3/2P5/8/8 w - - 0 1
go depth 58
ucinewgame
```

The PR (prior to a rewrite for clarity)

passed STC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65405 W: 12454 L: 12384 D: 40567 Elo +0.37
Ptnml(0-2): 920, 7256, 16285, 7286, 944
http://tests.stockfishchess.org/tests/view/5e441a3be70d848499f63d15

passed LTC:
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 27096 W: 3477 L: 3413 D: 20206 Elo +0.82
Ptnml(0-2): 128, 2215, 8776, 2292, 122
http://tests.stockfishchess.org/tests/view/5e44e277e70d848499f63d63

The incorrectly named VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were renamed into VALUE_TB_WIN_IN_MAX_PLY and VALUE_TB_LOSS_IN_MAX_PLY,
and correclty defined VALUE_MATE_IN_MAX_PLY and VALUE_MATED_IN_MAX_PLY
were introduced.

One further (corner case) mistake using these constants was fixed (go
mate X), which could lead to a premature return if X > MAX_PLY / 2,
but TB were present.

Thanks to @svivanov72 for one of the reports and help fixing the issue.

closes https://github.com/official-stockfish/Stockfish/pull/2552

Bench: 4932981
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Vizvezdenec
Date: Mon Feb 10 09:19:02 2020 +0100
Timestamp: 1581322742

Modify singular beta for ttPv positions.

This patch lowers singular beta for positions that have been in pv and are not pv nodes.
The idea of using ttpv && !PvNode improved scaling with TC and could be
useful for other search heuristics.

passed STC
http://tests.stockfishchess.org/tests/view/5e3f6d7ce70d848499f63bbc
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 154953 W: 29688 L: 29272 D: 95993 Elo +0.93
Ptnml(0-2): 2616, 17912, 36037, 18210, 2673

passed LTC
http://tests.stockfishchess.org/tests/view/5e405561e70d848499f63bfa
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 70974 W: 9305 L: 8932 D: 52737 Elo +1.83
Ptnml(0-2): 466, 6658, 20920, 6826, 569

closes https://github.com/official-stockfish/Stockfish/pull/2550

Bench: 4932981
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Joost VandeVondele
Date: Mon Feb 10 09:12:07 2020 +0100
Timestamp: 1581322327

Fix wrong assert.

can trigger an abort when compiling with debug=yes, and using 7men TB.
The assert should check that less than 8 pieces are in the key for each
side, matching the assumption that underlies the FEN string construction.
Also take explicitly care of a 'v' character in material strings.

Fixes an issue reported in the forum:
https://groups.google.com/d/msg/fishcooking/yoVC7etIpz0/7mS7ntZMBAAJ

closes https://github.com/official-stockfish/Stockfish/pull/2547

No functional change.
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Joost VandeVondele
Date: Wed Feb 5 15:32:29 2020 +0100
Timestamp: 1580913149

Small cleanups.

closes https://github.com/official-stockfish/Stockfish/pull/2532

Bench: 4869669
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Vizvezdenec
Date: Wed Feb 5 13:42:24 2020 +0100
Timestamp: 1580906544

Reintroduce king infiltration

This patch reintroduces the recently simplified king infiltration bonus
in initiative calculation, doubling its effect, and compensating more.

passed STC
http://tests.stockfishchess.org/tests/view/5e3476f630ae32da08941d5c
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 75323 W: 14434 L: 14140 D: 46749 Elo +1.36
Ptnml(0-2): 1231, 8729, 17528, 8826, 1331

passed LTC
http://tests.stockfishchess.org/tests/view/5e377353e70d848499f638c1
LLR: 2.94 (-2.94,2.94) {0.25,1.75}
Total: 171466 W: 22223 L: 21561 D: 127682 Elo +1.34
Ptnml(0-2): 1204, 15951, 50831, 16397, 1312

closes https://github.com/official-stockfish/Stockfish/pull/2545

Brench: 4869669
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: xoto10
Date: Sun Feb 2 07:11:49 2020 +0100
Timestamp: 1580623909

Simplify away king infiltration.

STC :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 91438 W: 17496 L: 17438 D: 56504 Elo +0.22
Ptnml(0-2): 1573, 10711, 21067, 10790, 1563
https://tests.stockfishchess.org/tests/view/5e34812630ae32da08941d65

LTC :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 40485 W: 5246 L: 5177 D: 30062 Elo +0.59
Ptnml(0-2): 289, 3818, 11976, 3812, 327
https://tests.stockfishchess.org/tests/view/5e354daee70d848499f6380c

closes https://github.com/official-stockfish/Stockfish/pull/2542

Bench: 5047825
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: xoto10
Date: Sat Feb 1 09:05:13 2020 +0100
Timestamp: 1580544313

Simplify Tweak late move reductions at root.

Revert change from Jan 15.

STC 10+0.1 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 65135 W: 12543 L: 12436 D: 40156 Elo +0.57
Ptnml(0-2): 1090, 7618, 14947, 7623, 1136
https://tests.stockfishchess.org/tests/view/5e334016708b13464ceea32e

LTC 60+0.6 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 17768 W: 2286 L: 2191 D: 13291 Elo +1.86
Ptnml(0-2): 128, 1602, 5273, 1679, 140
https://tests.stockfishchess.org/tests/view/5e34011e57e1ecae66ec2aab

closes https://github.com/official-stockfish/Stockfish/pull/2537

Bench: 4914050
see source
Windows x64 for Haswell CPUs
Windows x64 for modern computers
Windows x64
Windows 32
Linux x64 for Haswell CPUs
Linux x64 for modern computers
Linux x64
Author: Joost VandeVondele
Date: Fri Jan 31 19:48:44 2020 +0100
Timestamp: 1580496524

Revert 5 recent patches

Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:

http://tests.stockfishchess.org/tests/view/5e307251ab2d69d58394fdb9

This was discussed in depth in:

https://github.com/official-stockfish/Stockfish/issues/2531

Each patch was removed and tested as a simplification, full list below, and the whole combo as well.

After the revert the regression test showed a neutral result:

http://tests.stockfishchess.org/tests/view/5e334851708b13464ceea33c

As a result of this experience, the SPRT testing bounds will be made more strict.

Reverted patches:

1 Dynamic Complexity 6d0eabd5fe2961551477820ab7619e2c31e01ffd :

STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615 Elo +1.25
Ptnml(0-2): 677, 4346, 8843, 4545, 646

LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868 Elo +0.67
Ptnml(0-2): 270, 3556, 11429, 3584, 291

3 More bonus for bestMoves on past PV nodes 71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :

STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520 Elo +0.95
Ptnml(0-2): 796, 5297, 10749, 5387, 813

LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704 Elo +2.18
Ptnml(0-2): 115, 1498, 5006, 1569, 130

4 Tweak Restricted Piece Bonus 0ae00454ba6928d181b46103e5c83e6d58fcebe5 :

STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271 Elo +0.25
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581

LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767 Elo +0.85
Ptnml(0-2): 255, 3279, 10061, 3345, 262

5 History update for pruned captures 01b6088af39902001d2d6844561b6a2faa549282 :

STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218 Elo +1.73
Ptnml(0-2): 483, 3445, 6820, 3469, 545

LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566 Elo +1.52
Ptnml(0-2): 143, 2005, 6555, 2055, 164

6 Tweak trapped rook penalty 18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :

STC 10+0.1 https://tests.stockfishchess.org/tests/view/5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180 Elo +2.24
Ptnml(0-2): 390, 2834, 5659, 2933, 417

LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374 Elo +0.09
Ptnml(0-2): 690, 9107, 28738, 9034, 720

All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786 Elo +5.10
Ptnml(0-2): 52, 690, 2281, 781, 65

Bench: 5153165
see source

< prev page next page >