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 5.4.0/mingw 5.3.1 on Ubuntu 16.04.
2.Jan.2016: BMI build now slightly faster due to profiling.
Development builds for macOS are available at stockfishchess.de
Read the FAQ or leave a comment.

goto Gull
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: Stefan Geschwentner
Date: Sun Dec 3 10:41:48 2017 +0100
Timestamp: 1512294108

Attack threats

Give bonus for safe attack threats from bishops and rooks on opponent queen

STC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 8629 W: 1599 L: 1438 D: 5592
http://tests.stockfishchess.org/tests/view/5a1ad4490ebc590ccbb8b30d

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 7093 W: 987 L: 846 D: 5260
http://tests.stockfishchess.org/tests/view/5a1aec5d0ebc590ccbb8b317

Bench: 5051254
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: basepr1me
Date: Sat Nov 18 16:45:33 2017 +0100
Timestamp: 1511019933

OpenBSD friendly start.
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: Stefan Geschwentner
Date: Sat Nov 18 16:27:44 2017 +0100
Timestamp: 1511018864

Simplify good/bad capture detection. bench 5336313
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: Stefano Cardanobile
Date: Sat Nov 18 14:08:06 2017 +0100
Timestamp: 1511010486

Fix comments. Bench: 5109559.
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: Stéphane Nicolet
Date: Sat Nov 18 11:24:23 2017 +0100
Timestamp: 1511000663

Simplify away the PawnSet[] imbalance array (#1308)

Simplify away the PawnSet[] imbalance array

STC:
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 52977 W: 9550 L: 9484 D: 33943
http://tests.stockfishchess.org/tests/view/5a06b4780ebc590ccbb8a833

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 83717 W: 10599 L: 10559 D: 62559
http://tests.stockfishchess.org/tests/view/5a0aa36a0ebc590ccbb8aa99

Bench: 5340212
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: Rocky640
Date: Sat Nov 11 13:37:29 2017 +0100
Timestamp: 1510403849

Simplify some kingring penalties expressions

The new "weak" expression helps simplify the safe check calculations for rooks or minors, (but the end result for all the safe checks is the exactly the same as in current master)

The only functional change is for the "outer king ring" (for example, squares f3 g3 h3 when white king is on g1). In current master, there was a 191 penalty if any of these was not defended at all.
With this pr, there is this 191 penalty if any of these is not defended at all or is only defended by a white queen.

Tested as a simplification
STC
http://tests.stockfishchess.org/tests/view/59fb03d80ebc590ccbb89fee
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 66167 W: 12015 L: 11971 D: 42181
(against master (Update Copyright year inMakefile))

LTC
http://tests.stockfishchess.org/tests/view/5a0106ae0ebc590ccbb8a55f
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 15790 W: 2095 L: 1968 D: 11727
(against master (Handle BxN trade as good capture when history scor))

same as #1296 but rebased on latest master
bench: 5109559
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: ceebo
Date: Fri Nov 10 12:14:53 2017 +0100
Timestamp: 1510312493

Add comments to pos.see_ge()

In terms of technical changes this patch eliminates the return
statements from the main loop of pos.see_ge() and replaces two conditional
computations with a single bitwise negation.

No functional change
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: VoyagerOne
Date: Fri Nov 10 12:12:58 2017 +0100
Timestamp: 1510312378

Capture Stat Simplification- Bench: 5363761
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: Gian-Carlo Pascutto
Date: Wed Nov 8 13:45:14 2017 +0100
Timestamp: 1510145114

Always do MaxCardinality checks.

Stockfish currently relies on the "filter_root_moves" function also
having the side effect of clamping Cardinality against MaxCardinality
(the actual piece count in the tablebases). So if we skip this function,
we will end up probing in the search even without tablebases installed.

We cannot bail out of this function before this check is done, so move
the MultiPV hack a few lines below.
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 Nov 8 13:44:24 2017 +0100
Timestamp: 1510145064

Simplify Null Move Search condition

Removes depth condition, adjust parameters.

passed STC:
http://tests.stockfishchess.org/tests/view/5a008cbc0ebc590ccbb8a512
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 29282 W: 5317 L: 5210 D: 18755

passed LTC:
http://tests.stockfishchess.org/tests/view/5a00d8530ebc590ccbb8a541
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 26893 W: 3458 L: 3345 D: 20090

Bench: 5015773
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: Sun Nov 5 22:05:51 2017 +0100
Timestamp: 1509915951

Handle BxN trade as good capture when history score is good

STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 19374 W: 3499 L: 3294 D: 12581
http://tests.stockfishchess.org/tests/view/59fc23f50ebc590ccbb8a0bf

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 91030 W: 11680 L: 11274 D: 68076
http://tests.stockfishchess.org/tests/view/59fc43ad0ebc590ccbb8a0d0

Bench: 5482249
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: Stefan Geschwentner
Date: Fri Nov 3 13:57:18 2017 +0100
Timestamp: 1509713838

Introduce capture history table for capture move sorting

Introduce capture move history table indexed by moved piece,
target square and captured piece type for sorting capture moves.

STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 11374 W: 2096 L: 1924 D: 7354
http://tests.stockfishchess.org/tests/view/59fac8dc0ebc590ccbb89fc5

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 24791 W: 3196 L: 3001 D: 18594
http://tests.stockfishchess.org/tests/view/59fae4d20ebc590ccbb89fd9

Bench: 5536775
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 Nov 3 13:51:53 2017 +0100
Timestamp: 1509713513

Replace easyMove with simple scheme

Reduces time for a stable bestMove, giving some of the won time for the next move.

the version before the pvDraw passed both STC and LTC

passed STC:
http://tests.stockfishchess.org/tests/view/59e98d5a0ebc590ccbb896ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78561 W: 13945 L: 13921 D: 50695
elo = 0.106 +- 1.445 LOS: 55.716%

passed LTC:
http://tests.stockfishchess.org/tests/view/59eb9df90ebc590ccbb897ae
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 29056 W: 3640 L: 3530 D: 21886
elo = 1.315 +- 1.982 LOS: 90.314%

This version, rebased on pvDrawPR with the obvious change, was verified again on STC:

http://tests.stockfishchess.org/tests/view/59ee104e0ebc590ccbb89899
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19890 W: 3648 L: 3525 D: 12717
elo = 2.149 +- 2.895 LOS: 92.692%

and LTC:
http://tests.stockfishchess.org/tests/view/59f9673a0ebc590ccbb89ea0
Total : 17966
Win : 2273 ( 12.652%)
Loss : 2149 ( 11.961%)
Draw : 13544 ( 75.387%)
Score : 50.345%
Sensitivity : 0.014%
2*(W-L)/(W+L) : 5.608%

LLR [-3.0, 1.0] : 2.95

BayesElo range : [ -1.161, 4.876, 10.830] (DrawElo: 341.132)
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %

LTC again:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17966 W: 2273 L: 2149 D: 13544
LogisticElo range : [ -0.501, 2.105, 4.677]
LOS : 94.369 %

unchanged bench: 5234652
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: Cooffe
Date: Sat Oct 28 12:35:44 2017 +0200
Timestamp: 1509186944

Update Copyright year inMakefile

No functional change.
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 Oct 28 12:33:48 2017 +0200
Timestamp: 1509186828

Extra thinking before accepting draw PVs.

If the PV leads to a draw (3-fold / 50-moves) position
and we're ahead of time, think a little longer, possibly
finding a better way.

As this is most likely effective at higher draw rates,
tried speculative LTC after a yellow STC:

STC:
http://tests.stockfishchess.org/tests/view/59eb173a0ebc590ccbb8975d
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 56095 W: 10013 L: 9902 D: 36180
elo = 0.688 +- 1.711 LOS: 78.425%

LTC:
http://tests.stockfishchess.org/tests/view/59eba1670ebc590ccbb897b4
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 59579 W: 7577 L: 7273 D: 44729
elo = 1.773 +- 1.391 LOS: 99.381%

bench: 5234652
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: IIvec
Date: Sun Oct 22 07:43:37 2017 +0200
Timestamp: 1508651017

Fix premature using of all available time in x/y TC

In x/y time controls there was a theoretical possibility
to use all available time few moves before the clock will
be updated with new time. This patch fixes that issue.

Tested at 60/15 time control:

LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 113963 W: 20008 L: 20042 D: 73913

The test was done without adjudication rules!

Bench 5234652
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: Gian-Carlo Pascutto
Date: Sun Oct 22 07:18:48 2017 +0200
Timestamp: 1508649528

Don't filter root moves if MultiPV mode is enabled

A band-aid patch to workaround current TB code
limitations with multi PV.

Hopefully this will be removed after committing the
big update of TB impementation, now under discussion.

No functional change.
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: ceebo
Date: Sun Oct 22 07:00:46 2017 +0200
Timestamp: 1508648446

Add initiative to trace

No functional change
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 Oct 11 11:47:50 2017 +0200
Timestamp: 1507715270

Fix issue #1268

If the search is quit before skill.pick_best is called,
skill.best_move might be MOVE_NONE.

Ensure skill.best is always assigned anyhow.

Also retire the tricky best_move() and let the underlying
semantic to be clear and explicit.

No functional change.
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: Alain SAVARD
Date: Wed Oct 11 11:13:44 2017 +0200
Timestamp: 1507713224

Simplify bonus for bishop on long diagonal

Removing 2 conditions, and increase the ThreatbyPawn to compensate.

Passed STC
http://tests.stockfishchess.org/tests/view/59dbde900ebc5916ff64be6d
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 14236 W: 2615 L: 2483 D: 9138

Passed LTC
http://tests.stockfishchess.org/tests/view/59dc26470ebc5916ff64be92
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 16552 W: 2136 L: 2010 D: 12406

Bench: 5234652
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: Niklas Fiekas
Date: Thu Oct 5 11:00:01 2017 +0200
Timestamp: 1507194001

WLDEntryPiece -> WDLEntryPiece for consistency

No functional change.
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: Stéphane Nicolet
Date: Mon Oct 2 07:53:28 2017 +0200
Timestamp: 1506923608

Good bishops on the main diagonals

Bonus in midgame for bishops on long diagonals when the central squares are not occupied by pawns.

Author: ElbertoOne

Passed STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 10801 W: 1955 L: 1786 D: 7060
http://tests.stockfishchess.org/tests/view/59cf5c1d0ebc5916ff64b9da

and LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 83978 W: 10685 L: 10303 D: 62990
http://tests.stockfishchess.org/tests/view/59cf6f6c0ebc5916ff64b9e4

Bench: 5620312
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: VoyagerOne
Date: Sat Sep 30 20:56:27 2017 +0200
Timestamp: 1506797787

Decrease reduction for exact PV nodes

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 59004 W: 10621 L: 10249 D: 38134

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 25801 W: 3306 L: 3108 D: 19387

Bench: 5742466
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 Sep 29 16:39:12 2017 +0200
Timestamp: 1506695952

Measure nodes after search finished.

Only affects nmpsec in the multithreaded case.

No functional change.
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: GuardianRM
Date: Fri Sep 22 16:48:08 2017 +0200
Timestamp: 1506091688

Tweak statScore condition

The first change (ss->statScore >= 0) does nothing.

The second change ((ss-1)->statScore >= 0 ) has a massive change.
(ss-1)->statScore is not set until (ss-1) begins to apply LMR to moves.
So we now increase the reduction for bad quiets when our opponent is
running through the first captures and the hash move.

STC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 57762 W: 10533 L: 10181 D: 37048

LTC
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 19973 W: 2662 L: 2480 D: 14831

Bench: 5037819

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