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.

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!! latest version !!


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: Daniel Dugovic
Date: Mon Mar 27 15:55:48 2017 -0700
Timestamp: 1490655348

Add assertion for the maximum number of pawns

No functionl change

Closes #1039
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 Mar 25 17:57:07 2017 -0700
Timestamp: 1490489827

Introduce assert for stats update

Make sure updates to the stats are done in a stable way.

No functional change

Closes #1038
Closes #1037
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 Mar 25 10:35:17 2017 -0700
Timestamp: 1490463317

Increase maximum number of threads

a single Xeon Phi can present itself as a single numa node with up to 288 threads (4 threads per hardware core).
Tested to work as expected with a Xeon Phi CPU 7230 up to 256 threads.

No functional change

Closes #1045
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: joergoster
Date: Sat Mar 25 10:22:20 2017 -0700
Timestamp: 1490462540

Simplify ThreatBySafePawn scoring

Bench: 6197938

Closes #1047
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 Mar 25 10:13:25 2017 -0700
Timestamp: 1490462005

Singular extension and check extension tweak

If singular extension fails to trigger extension then don't consider check extension.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 69428 W: 12663 L: 12271 D: 44494

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 44023 W: 5875 L: 5612 D: 32536

Bench: 6170444

Closes #1043
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 Mar 18 15:44:49 2017 -0700
Timestamp: 1489877089

Skip quiet moves based on moveCount pruning threshold and history stats

If we can moveCountPrune and next quiet move has negative stats,
then go directly to the next move stage (Bad_Captures).

Reduction formula is tweaked to compensate for the decrease in move count that is used in LMR.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 6847 W: 1276 L: 1123 D: 4448

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 48687 W: 6503 L: 6226 D: 35958

Bench: 5919519

Closes #1036
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 Mar 17 14:46:47 2017 -0700
Timestamp: 1489787207

History stat bonus: Move condition to bonus calculation

about 0.5% speedup.

No functional change

Closes #1034
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: joergoster
Date: Fri Mar 17 14:41:08 2017 -0700
Timestamp: 1489786868

Pawns count imbalance table

Instead of having a continuous increasing bonus for our number of pawns when calculating imbalance, use a separate lookup array with tuned values.
Idea by GuardianRM.

STC
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 16155 W: 2980 L: 2787 D: 10388

LTC
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 100478 W: 13055 L: 12615 D: 74808

Bench: 6128779

Closes #1030
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: Marco Costalba
Date: Tue Mar 14 21:02:21 2017 -0700
Timestamp: 1489550541

Assorted code style fixes

No functional change

Closes #1029
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: mstembera
Date: Tue Mar 14 20:56:26 2017 -0700
Timestamp: 1489550186

Fix pawn entry prefetch

No functional change

Closes #1026
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: snicolet
Date: Wed Mar 8 18:45:38 2017 -0800
Timestamp: 1489027538

Helper functions to count material for both sides

Syntactic sugar: helper functions to count material or pieces for both sides.

No functional change

Closes #1025
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 Mar 8 18:35:23 2017 -0800
Timestamp: 1489026923

Always have counterMoves associated

Simplifies away all associated checks, leading to a ~0.5% speedup.
The code now explicitly checks if moves are OK, rather than using nullptr checks.

Verified for no regression:

LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32218 W: 5762 L: 5660 D: 20796

No functional change

Closes #1021
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: pb00068
Date: Wed Mar 8 18:03:01 2017 -0800
Timestamp: 1489024981

Further simplify skipping of plies with threads

No functional change

Closes #1020
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: Sun Mar 5 18:58:06 2017 -0800
Timestamp: 1488769086

Allow pruning advance pawn pushes if not near endgame

STC:
LLR: -2.95 (-2.94,2.94) [0.00,5.00]
Total: 101088 W: 18016 L: 17717 D: 65355

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 61194 W: 8108 L: 7791 D: 45295

Bench: 5803228

Closes #1023
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: snicolet
Date: Sun Mar 5 18:20:27 2017 -0800
Timestamp: 1488766827

Speed-up some arrays reading

This patch removes the empty rows at the beginning and at the end of
MobilityBonus[] and Protector[] arrays:

• reducing the size of MobilityBonus from 768 bytes to 512 bytes
• reducing the size of Protector from 1024 to 512 bytes

Also adds some comments and cleaner code for the arrays in pawns.cpp

No speed penalty (measured speed-up of 0.4%).

No functional change.

Closes #1018
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 Feb 26 16:41:58 2017 -0800
Timestamp: 1488156118

Simplify skipping of plies with helper threads

Replaces the HalfDensity array with an equivalent, compact implementation.
Includes suggestions by mcostalba & snicolet.

No functional change

Closes #1004
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: snicolet
Date: Sat Feb 25 17:43:54 2017 -0800
Timestamp: 1488073434

Change definition of "weak" in threats calculation

By defining "strongly protected" as "protected by a pawn, or protected
by two pieces and not attacked by two enemy pieces".

Passed STC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 17050 W: 3128 L: 2931 D: 10991

Passed LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 120995 W: 15852 L: 15343 D: 89800

Bench : 6269229

Closes #1016
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: mstembera
Date: Thu Feb 23 21:33:03 2017 -0800
Timestamp: 1487914383

Reorder members of Material::Entry

This eliminates alignment padding and reduces size from 48 to 40 bytes.
This makes the material HashTable smaller and more cache friendly.

No functional change

Closes #1013
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: Thu Feb 23 21:26:59 2017 -0800
Timestamp: 1487914019

Pieces protecting king

Initial protective idea by Snicolet for knight, for other pieces too
Patch add penalties and bonuses for pieces, depending on the distance from the own king

STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 21192 W: 3919 L: 3704 D: 13569

LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 26177 W: 3642 L: 3435 D: 19100

Bench : 6687377

Closes #1012
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: snicolet
Date: Sun Feb 19 14:27:03 2017 -0800
Timestamp: 1487543223

Keep pawns on both flanks

Positions with pawns on only one flank tend to be more drawish. We add
a term to the initiative bonus to help the attacking player keep pawns
on both flanks.

STC: yellowish run stopped after 257137 games
LLR: -0.92 (-2.94,2.94) [0.00,5.00]
Total: 257137 W: 46560 L: 45511 D: 165066

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 15602 W: 2125 L: 1956 D: 11521

Bench : 6976310

Closes #1009
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: FauziAkram
Date: Sun Feb 19 14:00:44 2017 -0800
Timestamp: 1487541644

Variable tuning

A tuning patch which cover the following changes:

increase the importance of queen and rook mobility in endgame and
decrease it in mg, since if we use the heavy pieces too early in the game
we will just make opponent develop their pieces by threatening ours.

King Psqt:
1)King will be encouraged more to stay in the first ranks in the MG
2)and will be encouraged more to go to the middle of the board/last ranks in the EG

Bishop scale better in EG
Logical changes on various psqt tables
1/6 of the changes of the last tuning session on mobility tables

STC: LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 227879 W: 41240 L: 40313 D: 146326
LTC : LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 167047 W: 21871 L: 21291 D: 123885

Bench: 5695960

Closes #1008
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 Feb 18 22:50:37 2017 -0800
Timestamp: 1487487037

Razor Simplification

Remove code that restrict using tt-moves for razoring.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 67442 W: 12039 L: 11997 D: 43406

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 38541 W: 5044 L: 4947 D: 28550

Bench: 5667216

Closes #1002
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: torfranz
Date: Tue Feb 14 21:26:08 2017 -0800
Timestamp: 1487136368

Retire loose enemies bonus

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 44727 W: 7943 L: 7862 D: 28922

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 148343 W: 19044 L: 19088 D: 110211

Bench: 5669076

Closes #1005
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: Tue Feb 14 21:22:58 2017 -0800
Timestamp: 1487136178

search(): Move nullValue variable into local scope

No functional change

Closes #1003
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: Tue Feb 14 21:11:44 2017 -0800
Timestamp: 1487135504

Fix makefile: 32 bit builds without optimization.

Fixes failing build for

make ARCH=x86-32 clean && make ARCH=x86-32 optimize=no build

by passing -m32 also to the link step.

Extend travis testing accordingly.

No functional change.

Closes #999

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