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: 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
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: Fri Feb 10 16:52:34 2017 -0800
Timestamp: 1486774354

Retire small bonus in passed pawn evaluation

STC: http://tests.stockfishchess.org/tests/view/5899824d0ebc59099759f3ee
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33370 W: 6061 L: 5961 D: 21348

LTC: http://tests.stockfishchess.org/tests/view/5899e3820ebc59099759f415
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 36206 W: 4664 L: 4563 D: 26979

Bench: 6072262

Closes #998
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: Joona Kiiski
Date: Fri Feb 10 16:44:13 2017 -0800
Timestamp: 1486773853

A small tweak in doEasyMove()

Time.elapsed() > Time.optimum() * 5 / 44
instaed of:
Time.elapsed() > Time.optimum() * 5 / 42

This was yellow on STC:
LLR: -2.96 (-2.94,2.94) [0.00,4.00]
Total: 156856 W: 28317 L: 27942 D: 100597

Passed on LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 36909 W: 4926 L: 4682 D: 27301

Note: Patch was originally submitted by user GuardianRM.
However his repo was deleted before merge.

No functional change

Closes #995
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: Stefano80
Date: Sun Feb 5 16:06:37 2017 -0800
Timestamp: 1486339597

Simplify scale factor computation

Minor non-functional simplifications in computing the scale factor.

In my opinion, the code is now slightly more readable:

- remove one condition which can never be satisfied.
- immediately return instead of assigning the sf variable.

Tested for non-regression:

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 62162 W: 11166 L: 11115 D: 39881

No functional change

Closes #992
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 Feb 5 15:40:30 2017 -0800
Timestamp: 1486338030

Simplify Queen Mobility

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 85997 W: 15550 L: 15540 D: 54907

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 25333 W: 3370 L: 3256 D: 18707

Bench: 6459194

Closes #991
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: Tue Jan 31 09:54:38 2017 +0100
Timestamp: 1485852878

Simplify away QueenContactChecks

Changing the definition of safe checks to include
squares protected only by the king, but twice
attacked by the opponent.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8691 W: 1683 L: 1541 D: 5467
http://tests.stockfishchess.org/tests/view/588f53b50ebc5915193f7dc7

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 31266 W: 4150 L: 4043 D: 23073
http://tests.stockfishchess.org/tests/view/588f68ab0ebc5915193f7dda

Bench : 5885815
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 Jan 29 08:54:58 2017 +0100
Timestamp: 1485676498

Simplify TT penalty stat (#980)

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 20251 W: 3692 L: 3570 D: 12989

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 16432 W: 2155 L: 2029 D: 12248

Bench: 5941174
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 Jan 28 09:32:07 2017 +0100
Timestamp: 1485592327

Penalty for a quiet ttMove that fails low

Also the penalty/bonus function is misleading, we
should simply change it to stat_bonus(depth) for
bonus and -stat_bonus(depth+ ONE_PLY) for extra
penalty.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 11656 W: 2183 L: 2008 D: 7465

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 11152 W: 1531 L: 1377 D: 8244

Bench: 6101931
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 Jan 28 09:04:24 2017 +0100
Timestamp: 1485590664

Candidate passed pawns

Detect safe candidate passers.

STC: http://tests.stockfishchess.org/tests/view/5882395c0ebc5915193f78b3
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 53569 W: 9925 L: 9570 D: 34074

LTC: http://tests.stockfishchess.org/tests/view/5882b4fb0ebc5915193f78e2
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 77576 W: 10387 L: 10014 D: 57175

Bench: 5325829
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: Sat Jan 28 08:43:54 2017 +0100
Timestamp: 1485589434

Simplify away pinnedPieces bitboard in EvalInfo (#975)

Results for 20 tests for each version (pgo-builds):

Base Test Diff
Mean 2110519 2118116 -7597
StDev 8727 4906 10112

p-value: 0,774
speedup: 0,004

Further verified for no regression:
http://tests.stockfishchess.org/tests/view/5885abd10ebc5915193f79e6
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 21786 W: 3959 L: 3840 D: 13987

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: Sat Jan 21 10:47:54 2017 +0100
Timestamp: 1484992074

Simplification of lazy threshold

Passed STC
http://tests.stockfishchess.org/tests/view/587846c10ebc5915193f74ec
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 217236 W: 39041 L: 39254 D: 138941

Passed LTC
http://tests.stockfishchess.org/tests/view/587e157a0ebc5915193f76e7
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 52396 W: 6883 L: 6804 D: 38709

This submitted version (using if (abs(mg + eg) > 1500) )
seems more logical than the following other green simplification (using if (abs(mg)>1500))
since it can happen than mg_value is > eg_value (about 20% of the time)
and the submitted version seems stronger at LTC

STC
http://tests.stockfishchess.org/tests/view/5879702d0ebc5915193f7585
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39958 W: 7315 L: 7227 D: 25416

LTC
http://tests.stockfishchess.org/tests/view/5879af3e0ebc5915193f7592
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 204322 W: 26529 L: 26648 D: 151145

bench: 6406285
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: Sat Jan 21 10:36:46 2017 +0100
Timestamp: 1484991406

Outpost array simplification

The ReachableOutpost values were almost exactly half the Outpost values.

Passed STC
http://tests.stockfishchess.org/tests/view/588020510ebc5915193f781e
LLR: 3.86 (-2.94,2.94) [-3.00,1.00]
Total: 119238 W: 21462 L: 21460 D: 76316

Passed LTC
http://tests.stockfishchess.org/tests/view/5880ae090ebc5915193f7843
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 23540 W: 3097 L: 2980 D: 17463

Curiously, using a division by 2, with slightly different values, did not passed
http://tests.stockfishchess.org/tests/view/587fece00ebc5915193f780a

bench: 5828283
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: Sat Jan 21 10:13:49 2017 +0100
Timestamp: 1484990029

Reformat eval_init()

Move more code into eval_init, removing some
clutter in the main routine.

Write eval_init only from "our" point of view
(do not init the attackedBy[Them] bitboards).

Add mobilityArea to the evalinfo

A few edits while being there

tested for non-regression at STC
http://tests.stockfishchess.org/tests/view/587fab230ebc5915193f77d9
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39585 W: 7183 L: 7094 D: 25308

Non 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: Tue Jan 17 14:50:03 2017 +0100
Timestamp: 1484661003

Update some comments (#973)

Use somewhat more precise comments in a couple of places.

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: Stefano Cardanobile
Date: Fri Jan 13 09:17:48 2017 +0100
Timestamp: 1484295468

Introduce lazy evaluation

After we have taken into account all cheap evaluation
terms, we check whether the score exceeds a given threshold.
If this is the case, we return a scaled down evaluation.

STC:
LLR: 3.35 (-2.94,2.94) [0.00,5.00]
Total: 12575 W: 2316 L: 2122 D: 8137

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 67480 W: 9016 L: 8677 D: 49787

Current version is the one rewritten by ceebo
further edited by me.

Bench: 5367704
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: loco-loco
Date: Thu Jan 12 08:46:46 2017 +0100
Timestamp: 1484207206

Removing CM parameter from the Stats struct. (#970)

After the history simplifications, we are only using Value Stats for CounterMoveHistory table. Therefore the parameter CM is not necessary.

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: Wed Jan 11 18:11:17 2017 +0100
Timestamp: 1484154677

Check for overflow in Score * int multiplication (#969)

Add asserts to check for overflow in Score * int multiplication.

There is no overflow in current master, but it would be easy to
create one as the scale of the current eval does not leave many
spare bits. For instance, adding the following unused variables
in master at the end of evaluate() (line 882 of evaluate.cpp)
overflows:

Score s1 = score * 4; // no overflow
Score s2 = score * 5; // overflow

Assertion failed: (eg_value(result) == (i * eg_value(s))),
function operator*, file ./types.h, line 336.

Same md5 checksum as current master for non debug compiles.

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: Rocky640
Date: Wed Jan 11 08:56:38 2017 +0100
Timestamp: 1484121398

StormDanger CleanUp (#964)

Order the enum and the array the same way they appear around line 250.
Makes it much easier to follow.

Add comments in the array definition and critical rows.
Use same terminology as elsewhere in pawns.cpp

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 Jan 11 08:46:29 2017 +0100
Timestamp: 1484120789

Adjust copyright headers to 2017 (#965)

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: Marco Costalba
Date: Wed Jan 11 08:44:06 2017 +0100
Timestamp: 1484120646

Travis: fix bench fetch in case of PR (#968)

When Travis tests a PR, a commit merge is created
but master branch is not updated, although HEAD is.

No functional change.

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