Stockfish 7 progress

clumma · Post by **clumma** » Sat Jan 16, 2016 10:59 pm

I'm always curious what might be learned from Stockfish's progress. Is it just accumulation of many small improvements, or are some changes more important than others?

This graph by Stefan Pohl makes Elo progress from SF6 to SF7 look non uniform, with a large bump in October

Does anyone know which changes these were?

-Carl

lucasart · Post by **lucasart** » Sun Jan 17, 2016 9:46 am

Below is the list of all functional changes (ie. excluding cosmetic patches) since SF6.

As usual, small streams make big rivers: no, there is no earth shattering patch that reinvents computer chess theory, just incremental tweaks.

The only really significant change is the rewrite of SMP in a simpler, and surprisingly more efficient way, so called lazy SMP. Congratulation to mbootsector for doing all the hard work.

Code: Select all

commit 74e2fa97b7ce49722b908f35988f3c75dee9bf36
Author: Stefano80 <stefano.cardanobile@gmail.com>
Date:   Wed Jan 13 16:05:31 2016 +0000

    Adjust reductions based on history and cmh tables
    
    STC:
    LLR: 4.06 (-2.94,2.94) [0.00,5.00]
    Total: 149395 W: 28029 L: 27208 D: 94158
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 9628 W: 1368 L: 1217 D: 7043
    
    bench: 8076724
    
    Resolves #565

commit aa31f7f096adef50fe119b41d4e7834c41fec310
Author: lucasart <lucas.braesch@gmail.com>
Date:   Sat Jan 2 09:10:12 2016 +0800

    Retire CenterBind
    
    And compensate in the PSQT.
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 27714 W: 5161 L: 5052 D: 17501
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 36354 W: 5008 L: 4909 D: 26437
    
    Bench: 8603285
    
    Resolves #556

commit 1de97337c2d53bdff0f1c3f362d232028ef736a5
Author: Alain SAVARD <support@multicim.com>
Date:   Sun Jan 3 14:15:29 2016 +0000

    Fine tuning of unsupported pawn penalty
    
    Adjust the unsupported pawn penalty when the pawn is supporting 2 pawns
    (for example g7 in f6-g7-h6)
    
    Passed STC
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 23833 W: 4384 L: 4158 D: 15291
    
    Passed LTC
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 42711 W: 5918 L: 5655 D: 31138
    
    Bench: 8390233
    
    Resolves #549

commit dd9cf305816c84c2acfa11cae09a31c4d77cc5a5
Author: Joona Kiiski <joona@zoox.com>
Date:   Sat Jan 2 20:26:02 2016 +0000

    Stockfish 7
    
    Bench: 8355485
    
    No functional change

commit 7cafbab529bbba596a47af1d1ee7495599c1eaea
Author: Joona Kiiski <joona@zoox.com>
Date:   Wed Dec 30 11:32:45 2015 +0000

    Stockfish 7 Beta 2
    
    Bench: 8355485
    
    No functional change

commit a5c76d69c346d620b6f7a300d4a33cc5867f4d64
Author: Joona Kiiski <joona@zoox.com>
Date:   Sun Dec 27 19:35:48 2015 +0000

    Stockfish 7 Beta 1
    
    Bench: 8355485
    
    No functional change

commit da34023cfcb856e95d8cbc0b80653ab0ee6af6d6
Author: Alain SAVARD <support@multicim.com>
Date:   Tue Dec 22 10:00:04 2015 +0000

    New mobility bonus
    
    Tuned the global mobility factor for each piece, as well as some +- delta,
    
    The master mobility factor was {266,334} and tuning gave
    {267, 362} +S(-2,-2) for the Knight
    {249, 328} +S( 0,-2) for the Bishop
    {298, 353} +S(1,1) for the Rook
    {265, 358} +S(2,-1) for the Queen
    
    Passed STC
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 49402 W: 9367 L: 9037 D: 30998
    
    and LTC
    LLR: 2.97 (-2.94,2.94) [0.00,5.00]
    Total: 26831 W: 3871 L: 3658 D: 19302
    
    Bench: 8355485
    
    Resolves #536

commit ed72a1e9ba37a9fa2674da8f46bb0597a1721c2d
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sat Dec 19 15:58:45 2015 -0500

    Remove killer move conditions from LMR
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 8459 W: 1619 L: 1477 D: 5363
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 32239 W: 4404 L: 4299 D: 23536
    
    Bench: 7597031
    
    Resolves #534

commit 38adb487ca37f276674d04e92dd3213f4d47cf72
Author: Guenther Demetz <guenther.demetz@wuerth-phoenix.com>
Date:   Fri Dec 18 21:55:07 2015 +0000

    Distinct iteration paths for Lazy SMP threads
    
    STC 5+0.1, threads 7
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 6026 W: 1047 L: 901 D: 4078
    
    LTC: 20+0.2, threads 7
    LLR: 2.95 (-2.94,2.94) [0.00,5.00]
    Total: 19739 W: 2910 L: 2721 D: 14108
    
    STC 5+0.1, threads 20
    LLR: 2.95 (-2.94,2.94) [0.00,5.00]
    Total: 2493 W: 462 L: 331 D: 1700
    
    LTC 30+0.3, threads 20
    ELO: 8.86 +-3.7 (95%) LOS: 100.0%
    Total: 8000 W: 1076 L: 872 D: 6052
    
    Bench: 8012530
    
    Resolves #525

commit 9fac5774f414ec4a2e86c6b0306f07de427cd5db
Author: Alain SAVARD <support@multicim.com>
Date:   Mon Dec 14 18:04:20 2015 +0000

    Threats retuned
    
    STC:
    
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 45239 W: 8913 L: 8591 D: 27735
    
    LTC:
    
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 21046 W: 3200 L: 2989 D: 14857
    
    Bench: 8012530
    
    Resolves #526

commit 8315620522dd268755f32be792802abb62f7366f
Author: absimaldata <adpq11@gmail.com>
Date:   Wed Dec 2 01:27:05 2015 +0530

    New Tuned Weights
    
    More accurate evaluation weights
    
    Performed better at STC
    
    LLR: 1.32 (-2.94,2.94) [0.00,4.00]
    Total: 190043 W: 37433 L: 36675 D: 115935
    
    Passed LTC
    
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 30157 W: 4540 L: 4303 D: 21314
    
    Bench: 9264977
    
    Resolves #515

commit 5a42427cb882f8adcfe65d41f4fabac5d2ac4a5b
Author: Stéphane Nicolet <cassio@free.fr>
Date:   Thu Nov 26 10:15:51 2015 +0100

    Introduce new Threats weights = {350, 256}
    
    Raise the midgame threats weight by 37%.
    
    Passed STC:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 8165 W: 1675 L: 1487 D: 5003
    
    and LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 28181 W: 4141 L: 3912 D: 20128
    
    Bench: 7824961
    
    Resolves #512

commit 07e0741dfbca07097f38e46f3f7752b48675a515
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sun Nov 15 20:38:01 2015 -0800

    History Pruning: Don't prune the main killer move.
    
    Also increased pruned depth to 4.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 23380 W: 4581 L: 4350 D: 14449
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 28934 W: 4329 L: 4105 D: 20500
    
    Bench: 8369743
    
    Resolves #498

commit cccf3c815c2f2be884fac4248a2be91b6823df8a
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Sat Nov 14 06:30:50 2015 -0800

    Bonus for reachable outpost
    
    Give a bonus for outpost squares which in reach of a bishop or knight.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 22725 W: 4570 L: 4339 D: 13816
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 15019 W: 2333 L: 2157 D: 10529
    
    Bench: 8503181
    
    Resolves #495

commit 9c9205860c5ab0e4f3180298e3f7082be259772c
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Tue Nov 3 11:15:14 2015 +0100

    Get rid of timer thread
    
    Unfortunately std::condition_variable::wait_for()
    is not accurate in general case and the timer thread
    can wake up also after tens or even hundreds of
    millisecs after time has elapsded. CPU load, process
    priorities, number of concurrent threads, even from
    other processes, will have effect upon it.
    
    Even official documentation says: "This function may
    block for longer than timeout_duration due to scheduling
    or resource contention delays."
    
    So retire timer and use a polling scheme based on a
    local thread counter that counts search() calls and
    a small trick to keep polling frequency constant,
    independently from the number of threads.
    
    Tested for no regression at very fast TC 2+0.05 th 7:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 32969 W: 6720 L: 6620 D: 19629
    
    TC 2+0.05 th 1:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 7765 W: 1917 L: 1765 D: 4083
    
    And at STC TC, both single thread
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 15587 W: 3036 L: 2905 D: 9646
    
    And with 7 threads
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 8149 W: 1367 L: 1227 D: 5555
    
    bench: 8639247

commit aa242d2f84eaf2307f34d5356079125eaf5ff26a
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Fri Oct 30 16:39:21 2015 -0400

    New History Bonus Formula
    
    bonus = d^2 + d - 1
    
    Bench: 8639247
    
    Resolves #484

commit 55758344d3ccf49353bcd8f3a06a4553ff1b753a
Author: Alain SAVARD <support@multicim.com>
Date:   Sun Oct 18 22:17:37 2015 -0400

    Simplify threats
    
    Using less parameters and code to compute Threats
    Includes also a few spacing edits.
    
    Run as a simplification.
    
    Passed STC 10+0.1
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 18879 W: 3725 L: 3600 D: 11554
    
    Passed LTC 60+0.4
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 74116 W: 11001 L: 10958 D: 52157
    
    bench: 8004751

commit 4eca981e557704f4ce3db829adf380b8fc058926
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Wed Oct 21 18:21:23 2015 -0400

    History pruning
    
    Prune moves with negative History
    and CMH scores at low depth.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 24182 W: 4672 L: 4439 D: 15071
    
    LTC:
    LLR: 2.97 (-2.94,2.94) [0.00,5.00]
    Total: 12579 W: 1959 L: 1792 D: 8828
    
    bench: 8907701

commit 328d314f2faa128f6bed32e334190cdaed62d9bc
Author: Stefano80 <stefano.cardanobile@gmail.com>
Date:   Tue Oct 20 19:46:06 2015 -0700

    Almost passed tuning attempts
    
    Collect and give a second try to some almost passed tuning attempts and
    one-line tweaks from the last month.
    
    Passed STC
    
    LLR: 3.07 (-2.94,2.94) [0.00,4.00]
    Total: 15124 W: 2974 L: 2756 D: 9394
    
    And LTC
    
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 21577 W: 3507 L: 3289 D: 14781
    
    Bench: 8855226
    
    Resolves #464

commit ecc5ff6693f116f4a8ae5f5080252f29b279c0a1
Author: mbootsector <mbootsector@gmail.com>
Date:   Tue Oct 6 08:15:17 2015 +0200

    Lazy SMP
    
    Start all threads searching on root position and
    use only the shared TT table as synching scheme.
    
    It seems this scheme scales better than YBWC for
    high number of threads.
    
    Verified for nor regression at STC 3 threads
    LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 40232 W: 6908 L: 7130 D: 26194
    
    Verified for nor regression at LTC 3 threads
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 28186 W: 3908 L: 3798 D: 20480
    
    Verified for nor regression at STC 7 threads
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 3607 W: 674 L: 526 D: 2407
    
    Verified for nor regression at LTC 7 threads
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 4235 W: 671 L: 528 D: 3036
    
    Tested with fixed games at LTC with 20 threads
    ELO: 44.75 +-7.6 (95%) LOS: 100.0%
    Total: 2069 W: 407 L: 142 D: 1520
    
    Tested with fixed games at XLTC (120secs) with 20 threads
    ELO: 28.01 +-6.7 (95%) LOS: 100.0%
    Total: 2275 W: 349 L: 166 D: 1760
    
    Original patch of mbootsector, with additional work
    from Ivan Ivec (log formula), Joerg Oster (id loop
    simplification) and Marco Costalba (assorted formatting
    and rework).
    
    Bench: 8116244

commit 7ea5659c5fe0325f1b6ee5fec06ecd0f066e81c3
Author: Stéphane Nicolet <cassio@free.fr>
Date:   Thu Oct 15 21:27:52 2015 -0700

    Asymmetry bonus for the attacking side
    
    Use asymmetry in the position (king separation, pawn structure) to
    compute an "initiative bonus" for the attacking side.
    
    Passed STC:
    LLR: 2.95 (-2.94,2.94) [0.00,5.00]
    Total: 14563 W: 2826 L: 2636 D: 9101
    
    And LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 14363 W: 2317 L: 2141 D: 9905
    
    Bench: 8116244
    
    Resolves #462

commit 8fd34d7763072fc3ec7216729c1f7b7354bfa470
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Mon Oct 12 14:00:54 2015 -0700

    Combination of two ideas:
    
    Apply bonus for the prior CMH that caused a fail low.
    
    Balance Stats: CMH and History bonuses are updated differently.
    This eliminates the "fudge" factor weight when scoring moves. Also
    eliminated discontinuity in the gravity history stat formula. (i.e. stat
    scores will no longer inverse when depth exceeds 22)
    
    STC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 21802 W: 4107 L: 3887 D: 13808
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 46036 W: 7046 L: 6756 D: 32234
    
    Bench: 7677367

commit 55b46ffa909cf3873e4ac7129e324ed3eb1d0124
Author: Jonathan Calovski <jonoface@live.com.au>
Date:   Wed Oct 7 19:48:54 2015 +1100

    Retire rook contact checks
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 34114 W: 6363 L: 6265 D: 21486
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 61776 W: 9349 L: 9289 D: 43138
    
    LTC (after rebasing):
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 15261 W: 2343 L: 2214 D: 10704
    
    Bench: 7523382
    
    Resolves #442

commit 436c3037310ad997f85a5da0685b6bc91699163b
Author: Stefano80 <stefano.cardanobile@gmail.com>
Date:   Mon Oct 5 19:48:47 2015 -0700

    Tuning of assorted values
    
    Passed STC
    
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 45401 W: 8590 L: 8274 D: 28537
    
    Passed LTC
    
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 36089 W: 5589 L: 5331 D: 25169
    
    Bench: 8397672
    
    Resolves #445

commit 540b49a1522440597501aa94618cf391cef08feb
Author: Alain SAVARD <support@multicim.com>
Date:   Tue Oct 6 03:32:26 2015 +0100

    Remove queen threat evaluation
    
    Threats by queen seem to be worthless.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 13627 W: 2607 L: 2473 D: 8547
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 19146 W: 2950 L: 2827 D: 13369
    
    Bench: 8222484
    
    Resolves #439

commit 83e19fbed539fc05626d82afefde730bdcb344ab
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Sat Oct 3 03:46:53 2015 -0700

    File based passed pawn bonus
    
    Add file based bonus for passed pawns. Values tuned by SPSA.
    
    STC:
    LLR: 3.33 (-2.94,2.94) [0.00,5.00]
    Total: 36889 W: 6805 L: 6507 D: 23577
    
    LTC:
    LLR: 2.97 (-2.94,2.94) [0.00,5.00]
    Total: 32301 W: 5101 L: 4858 D: 22342
    
    Bench: 8073614
    
    Resolves #436

commit 9f5b31c21df72f60ab02417940ae573621ee7b90
Author: Jonathan Calovski <jonoface@live.com.au>
Date:   Sat Oct 3 03:36:51 2015 -0700

    Bonus for checking moves
    
    STC:
    LLR: 2.97 (-2.94,2.94) [0.00,5.00]
    Total: 14531 W: 2765 L: 2576 D: 9190
    
    LTC:
    LLR: 3.20 (-2.94,2.94) [0.00,5.00]
    Total: 52518 W: 8107 L: 7782 D: 36629
    
    Bench: 7556477
    
    Resolves #435

commit 77b4f4c2e735a3f1173d74ce904db9dae262a682
Author: Jonathan Calovski <jonoface@live.com.au>
Date:   Sat Sep 19 08:28:26 2015 +1000

    Refine ranks and increase resulting bonus.
    
    STC:
    LLR: 2.94 (-2.94,2.94) [0.00,4.00]
    Total: 272379 W: 51773 L: 50658 D: 169948
    
    LTC:
    LLR: 3.06 (-2.94,2.94) [0.00,4.00]
    Total: 41504 W: 6555 L: 6273 D: 28676
    
    bench: 7658406
    
    Resolves #430

commit 660c38f781060f1382b4b0b6e9a8b25658559820
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Tue Sep 15 05:55:09 2015 -0700

    Scales the endgame score by the number of pawns.
    
    Credits goes also to Stephane Nicolet for his great idea of scaling by pawns.
    
    STC:
    LLR: 2.95 (-2.94,2.94) [0.00,5.00]
    Total: 9994 W: 1929 L: 1760 D: 6305
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,5.00]
    Total: 11240 W: 1789 L: 1626 D: 7825
    
    bench 7298564
    
    Resolves #423

commit 7f300a769848c695fb28da444b0c3f4c1d919945
Author: Joona Kiiski <joona.kiiski@gmail.com>
Date:   Tue Aug 25 20:52:44 2015 +0100

    History gravity
    
    Instead of using hard coded Min and Max values for history,
    always adjust the old value slightly downwards before adding a new value.
    
    The adjustment acts like gravity that prevents the value escaping too
    far from zero.
    
    Bench: 8020484
    
    Resolves #407

commit 7ad85fca6d0ce5a8e62be67de7ec3d396670ca74
Author: lucasart <lucas.braesch@gmail.com>
Date:   Tue Aug 25 19:46:37 2015 +0800

    Prune castling moves
    
    Align the behaviour with reductions. Initially castling moves had to be
    treated differently, because the SEE did not handle them correctly. But now it
    does.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 83750 W: 15722 L: 15711 D: 52317
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 97183 W: 15120 L: 15115 D: 66948
    
    bench 7759837
    
    Resolves #403

commit 69a1a808c8ed02332914afbb503f3d96fa8bb093
Author: Alain SAVARD <support@multicim.com>
Date:   Mon Aug 17 19:30:17 2015 +0100

    Retire PawnSafePush bonus
    
    PawnSafePush, with the value S(5,5) proved not "necessary"
    possibly due to recent changes to MobilityArea and other changes to Connected bonus.
    
    STC:
    LLR: 3.22 (-2.94,2.94) [-3.00,1.00]
    Total: 98528 W: 18757 L: 18759 D: 61012
    
    LTC:
    LLR: 5.30 (-2.94,2.94) [-3.00,1.00]
    Total: 204194 W: 31698 L: 31734 D: 140762
    
    Bench: 7620871
    
    Resolves #396

commit 9dbb3ae8b2c5ef4ad2b399a42707ad1fd851c68b
Author: mstembera <MissingEmail@email>
Date:   Sat Aug 15 12:22:54 2015 +0100

    TT entry value based on depth and relative age
    
    Calculate TT replace value as depth minus eight times relative age.
    
    STC 2MB
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 45258 W: 8595 L: 8279 D: 28384
    
    LTC 8MB
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 56401 W: 8809 L: 8489 D: 39103
    
    STC 16MB
    LLR: 2.96 (-2.94,2.94) [-4.00,0.00]
    Total: 34764 W: 6565 L: 6529 D: 21670
    
    Bench: 9069474
    
    Resolves #395

commit f4ace94f91c31631a280b929d50fbe7077305dc2
Author: DiscanX <discan123@gmail.com>
Date:   Mon Aug 10 01:25:41 2015 +0800

    Tuned values for mid and end game passed pawns.
    
    STC :
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 22691 W: 4468 L: 4228 D: 13995
    
    LTC :
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 13620 W: 2216 L: 2023 D: 9381
    
    Bench: 8384669
    
    Resolves #391

commit 1aae35b8b7caec936c77fc981a8868d5b237d05b
Author: mstembera <MissingEmail@email>
Date:   Sat Aug 8 03:06:32 2015 -0700

    Revert TT replacement strategy changes (#380)
    
    It could cause problems with high depths and long time controls
    
    Bench: 8626315
    
    Resolves #390

commit 68d61b80c60a81055a2ffb2e251a237b979e9b31
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Tue Jul 28 12:53:13 2015 +0200

    Simplify IID depth formula
    
    Restore original formula messed up during
    half-ply removal.
    
    STC
    LLR: 4.11 (-2.94,2.94) [-3.00,1.00]
    Total: 21349 W: 4091 L: 3909 D: 13349
    
    LTC
    LLR: 5.42 (-2.94,2.94) [-3.00,1.00]
    Total: 52819 W: 8321 L: 8122 D: 36376
    
    bench: 8040572

commit a2410227cc8df5373d6970bfe63bbd3df5287c8c
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Thu Jul 30 00:50:45 2015 +0800

    PV refutation penalty
    
    Extra penalty for PV move in previous ply when it gets refuted.
    
    STC:
    LLR: 4.49 (-2.94,2.94) [-1.50,4.50]
    Total: 41094 W: 7889 L: 7620 D: 25585
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 12304 W: 1967 L: 1811 D: 8526
    
    Bench: 8373608
    
    Resolves #386

commit 4a6d59c6c7caa8a9055197280ea7bdcd072feeaa
Author: Alain SAVARD <support@multicim.com>
Date:   Thu Jul 30 00:47:51 2015 +0800

    MobilityArea (simplified)
    
    Based off of Pull request #383:
    
    Include squares occupied by some pawns in the MobilityArea
    a) not blocked
    b) on rank 4 and above
    c) or captures
    
    Passed STC
    LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
    Total: 8157 W: 1644 L: 1516 D: 4997
    
    And LTC
    LLR: 2.97 (-2.94,2.94) [0.00,6.00]
    Total: 26086 W: 4274 L: 4051 D: 17761
    
    -----------
    
    Then, a simplification test failed, trying to remove b and c)
    LLR: -2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 6048 W: 1117 L: 1288 D: 3643
    
    Another simplification test, was run to remove just (c)
    Passed STC
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 28073 W: 5364 L: 5255 D: 17454
    
    And LTC
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 34652 W: 5448 L: 5348 D: 23856
    
    A parameter tweak test showed that changing b) for "on rank 3 and above"
    does not work
    LLR: -2.95 (-2.94,2.94) [0.00,4.00]
    Total: 5233 W: 937 L: 1077 D: 3219
    
    Finally, a small rewrite, and we have this version
    
    Include squares occupied by some pawns in the MobilityArea which are
    a) not blocked
    b) on rank 4 and above
    
    Bench: 8977899
    
    Resolves #385

commit 51330414c4a773a9c3d1dd562fdc8536344a67b8
Author: mstembera <MissingEmail@email>
Date:   Sat Jul 25 00:33:53 2015 +0800

    Tuned version of TT replacement policy
    
    If the used multiplier of 8 was any number larger than DEPTH_MAX
    this would be a non functional patch.
    
    STC 2MB
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 16353 W: 3216 L: 3066 D: 10071
    http://tests.stockfishchess.org/tests/view/55a6d0630ebc590abbe1babd
    
    LTC 8MB
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 134618 W: 21276 L: 20716 D: 92626
    http://tests.stockfishchess.org/tests/view/55a74d760ebc590abbe1bad6
    
    STC 16MB
    LLR: 2.96 (-2.94,2.94) [-4.00,0.00]
    Total: 22549 W: 4257 L: 4178 D: 14114
    http://tests.stockfishchess.org/tests/view/55a9a2f90ebc590abbe1bb16
    
    Bench: 7372460
    
    Resolves #380

commit 1d977aa79ecaf410f4b2065eb8f11e0a5e689db4
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Mon Jul 13 18:19:09 2015 -0400

    LMR Simplification: Remove countermove condition
    
    Removed countermove condition for decreasing reduction.
    
    LTC:
    LLR: 3.01 (-2.94,2.94) [-3.00,1.00]
    Total: 32410 W: 5092 L: 4986 D: 22332
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 24450 W: 4632 L: 4517 D: 15301
    
    Bench: 6943812
    
    Resolves #378

commit d8aeaab79ca6809f8ad6a650611e827a7cba8978
Author: mstembera <MissingEmail@email>
Date:   Wed Jul 15 20:15:14 2015 +0100

    Consistent TT replace policy
    
    This fixes an inconsistency bug where TT entries were valued differently
    depending on which pointer they were accessed through.
    
    STC 2MB
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 11301 W: 2176 L: 2038 D: 7087
    
    LTC 8MB
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 17732 W: 2870 L: 2745 D: 12117
    
    STC 16MB
    LLR: 2.96 (-2.94,2.94) [-4.00,0.00]
    Total: 17401 W: 3324 L: 3227 D: 10850
    
    Bench: 8248164
    
    Resolves #377

commit b2edac7075ca238326378cb2c5ef09f7cdb2fd9e
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Tue Jun 30 13:50:59 2015 +0200

    Remove useless razoring condition
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 20626 W: 3977 L: 3855 D: 12794
    
    LTC:
    LLR: 3.10 (-2.94,2.94) [-3.00,1.00]
    Total: 87334 W: 13675 L: 13648 D: 60011
    
    Retire also the now unused pawn_on_7th() helper.
    
    bench: 8248166

commit aa0dc16b754f65e5f5b84c7500732476ca1f035b
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sat Jun 27 12:19:42 2015 -0400

    CMH Fix: Exclude captures for TT move refutation penalty
    
    This will make sure we store only quiet moves for TT Penalty.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 34748 W: 6617 L: 6420 D: 21711
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 19975 W: 3259 L: 3137 D: 13579
    
    Bench: 8063826
    
    Resolves #373

commit 7e9f776fcafe0121c7449f4339b26d77c14adf50
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sat Jun 27 09:41:17 2015 +0100

    LMR Tweak: Decrease reduction if cmh>0 && history>0.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 9627 W: 1879 L: 1748 D: 6000
    
    LTC:
    LLR: 2.97 (-2.94,2.94) [0.00,6.00]
    Total: 21543 W: 3433 L: 3234 D: 14876
    
    Bench: 8646407
    
    Resolves #370 #371

commit ad87d707fffeeac9aa1ae3e3e8d6fa2449ea1df9
Author: lucasart <lucas.braesch@gmail.com>
Date:   Sun Jun 7 09:49:01 2015 +0100

    Simplify outpost evaluation
    
    STC
    
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 114149 W: 21986 L: 22032 D: 70131
    
    LTC
    
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 52232 W: 8468 L: 8396 D: 35368
    
    Bench: 6716940
    
    No functional change
    
    Resolves #363

commit 7b8ffe0f5d89784c6b360331a7781604305371d9
Author: Vince Negri <vince.negri@gmail.com>
Date:   Sun May 31 10:52:41 2015 +0100

    Remove intermediate re-search in LMR
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 20149 W: 3830 L: 3707 D: 12612
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 45384 W: 7089 L: 7006 D: 31289
    
    Bench: 8110365
    
    Resolves #361

commit 5ebdf2f8c857681309e60d831f4f56452fb81235
Author: lucasart <lucas.braesch@gmail.com>
Date:   Tue Jun 2 12:08:35 2015 -0700

    Tune pawn shelter/storm
    
    STC
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 31679 W: 6183 L: 5912 D: 19584
    
    LTC
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 43550 W: 6885 L: 6602 D: 30063
    
    Bench: 9219343
    
    Resolves #360

commit 4502a1934f2d624288b635b5901ecda8cefa342c
Author: Stéphane Nicolet <cassio@free.fr>
Date:   Tue Jun 2 12:06:46 2015 -0700

    Tweak backward pawns definition
    
    Advanced pawns cannot be backward. Also lower the backward penalty in
    endgame.
    
    Passed STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 18534 W: 3588 L: 3433 D: 11513
    
    and LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,6.00]
    Total: 21319 W: 3415 L: 3217 D: 14687
    
    Bench: 7271152
    
    Resolves #359

commit 8e95c39bfa97e6248d9686b47dc4361f23fda06f
Author: lucasart <lucas.braesch@gmail.com>
Date:   Fri May 22 18:39:36 2015 +0800

    Simplify backward pawn scoring
    
    STC
    
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 52322 W: 10011 L: 9945 D: 32366
    
    LTC
    
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 14143 W: 2334 L: 2203 D: 9606
    
    Bench: 7976423
    
    Resolves #354

commit 2e0ec4ad6fe3eaf3c4194eb9da2b49bad5bf29b2
Author: lucasart <lucas.braesch@gmail.com>
Date:   Thu May 21 19:52:25 2015 +0800

    Fix merge error for Tuned PSQT
    
    Fall-out from 411e704f
    
    Bench: 7907776
    
    Resolves #352

commit e14046517ed0a690c0969b3ca8d1b0e25ac9fb9e
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Mon May 18 13:58:13 2015 -0700

    Remove Gain Stats
    
    Additionally in futility pruning the margin is raised for compensation.
    
    STC
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 48481 W: 9229 L: 9156 D: 30096
    
    LTC
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 32058 W: 5134 L: 5031 D: 21893
    
    Bench: 8098149
    
    Resolves #350

commit 411e704fdf5afac1bbfa8a28b86751501e0eed95
Author: lucasart <lucas.braesch@gmail.com>
Date:   Sat May 16 09:12:36 2015 +0800

    Tuned PSQT
    
    STC:
    LLR: 3.11 (-2.94,2.94) [-0.50,4.50]
    Total: 58764 W: 11530 L: 11185 D: 36049
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,4.50]
    Total: 282710 W: 46339 L: 45209 D: 191162
    
    Bench: 8512947
    
    Resolves #349

commit eaeb63f1d03aa71edf719605a31d121bf086a03d
Author: mstembera <MissingEmail@email>
Date:   Sat May 9 17:43:57 2015 +0100

    Smart TT save
    
    Don't overwrite more valuable data with less valuable data
    
    STC 2MB
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 21132 W: 4108 L: 3946 D: 13078
    http://tests.stockfishchess.org/tests/view/5547d59f0ebc5940ca5d6883
    
    LTC 8MB
    LLR: 2.97 (-2.94,2.94) [0.00,6.00]
    Total: 13381 W: 2149 L: 1987 D: 9245
    http://tests.stockfishchess.org/tests/view/5549b5a80ebc5940ca5d68b9
    
    STC 16MB regression w/ zero effective hash pressure
    LLR: 2.96 (-2.94,2.94) [-5.00,0.00]
    Total: 18944 W: 3607 L: 3564 D: 11773
    http://tests.stockfishchess.org/tests/view/554b0fda0ebc5940ca5d68ea
    
    Bench: 8787152
    
    Resolves #347

commit 946fa4762539307dcdcb30d08f13d627864e9bcf
Author: lucasart <lucas.braesch@gmail.com>
Date:   Tue May 5 19:10:19 2015 +0800

    Never clear stats
    
    Based on an idea and patch by VoyagerOne.
    
    Small simplification, but was tedted for an ELO gain anyway.
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-1.00,4.00]
    Total: 5375 W: 1119 L: 977 D: 3279
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,5.00]
    Total: 17893 W: 2984 L: 2792 D: 12117
    
    bench 8322847

commit 59f64fda4fffe595d53183caae94b1d9a2062f32
Author: Stefano80 <stefano.cardanobile@gmail.com>
Date:   Sun May 3 10:18:38 2015 -0700

    Improve ordering of good captures using rank term
    
    Rank based term improved approximation of pos.see() for scoring good
    captures.
    
    STC
    LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
    Total: 4632 W: 945 L: 827 D: 2860
    
    LTC
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 25770 W: 4184 L: 3964 D: 17622
    
    Bench: 7593704
    
    Resolves #342

commit cc54a91ca508e68bf84715a50f84c79f66b8f109
Author: Stefano80 <stefano.cardanobile@gmail.com>
Date:   Tue Apr 28 22:06:18 2015 +0100

    Replace MVV/LVA by MVV for good captures
    
    Passed STC
    
    LLR: 3.71 (-2.94,2.94) [-3.00,1.00]
    Total: 64363 W: 12299 L: 12214 D: 39850
    
    and LTC
    
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 69976 W: 11056 L: 11011 D: 47909
    
    Bench: 8012532
    
    Resolves #340

commit b7063ef65b4a5720e1d594beb50aaaca6fb11d93
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sun Apr 26 20:12:25 2015 +0100

    Change extra ply LMR condition to: cmh <= 0 && hist < 0
    
    Extra ply LMR condition is now cmh <= 0 && h < 0
    Instead of cmh + h < 0
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 55210 W: 10812 L: 10557 D: 33841
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 13212 W: 2239 L: 2045 D: 8928
    
    Bench: 8420865
    
    Resolves #339

commit 078625e33389536addc9f94b7fc197230ef2f0fb
Author: Alain SAVARD <support@multicim.com>
Date:   Sat Apr 18 22:12:56 2015 +0100

    Exclude queen from Rook Contact Check computation
    
    In ei.attackedBy, Queen does not x-ray through Rook, but the Rook does
    X-ray through the Queen.
    
    So most of the rook contact checks supported by queen are, in fact,
    Queen Contact Checks and they are already scored separately.
    
    Bench: 7762189
    
    Resolves #338

commit 20e92895af45ec9599110506eea231fc689c05ba
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Fri Apr 10 17:50:19 2015 -0400

    Removed extra condition (history < 0) in LMR to help sync up with move ordering.
    
    LMR condition is now cmh+history<0
    Instead of history<0 OR cmh+history<0
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-3.00, 1.00]
    Total: 26446 W: 5092 L: 4980 D: 16374
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [-3.00, 1.00]
    Total: 14129 W: 2340 L: 2209 D: 9580
    
    Bench: 7815183
    
    Resolves #331

commit 27efc5ac996ffc679395317c8bbb16aca996296c
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Fri Apr 10 20:32:39 2015 +0100

    Update stats at pv nodes
    
    If a quiet best move is found at a pv node then always update stats.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 41485 W: 8047 L: 7830 D: 25608
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,6.00]
    Total: 14351 W: 2420 L: 2250 D: 9681
    
    Bench: 6985247
    
    Resolves #330

commit 36f2133df3e5aea1436a17ae20f3a0d488be31bd
Author: mstembera <MissingEmail@email>
Date:   Fri Apr 10 20:09:45 2015 +0100

    New formula for quiet move scoring: 3 * cmh + 1 * hist
    
    STC
    
    LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
    Total: 45363 W: 8759 L: 8532 D: 28072
    
    LTC
    
    LLR: 3.51 (-2.94,2.94) [0.00,4.00]
    Total: 125092 W: 20032 L: 19468 D: 85592
    
    Bench: 7058819
    
    Resolves #328

commit ef4d89c9bd4fff869f9b57d7f5fcdacdfd46f91c
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Sun Apr 5 20:36:11 2015 +0200

    update stats also in check
    
    Update stats also if in check (drop condition).
    
    STC:
    LLR: 3.22 (-2.94,2.94) [-3.00,1.00]
    Total: 87472 W: 16929 L: 16913 D: 53630
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 39971 W: 6436 L: 6345 D: 27190
    
    Bench: 7086031
    
    Resolves #327

commit aaf17326e2db5f8bc6664c69e1c3e7fe59cde4ec
Author: lucasart <lucas.braesch@gmail.com>
Date:   Sat Apr 4 08:00:15 2015 +0800

    Prune evasions when we can castle
    
    A minor simplification.
    
    STC:
    
    LLR: 2.95 (-2.94,2.94) [-3.50,0.50]
    Total: 67877 W: 12882 L: 12904 D: 42091
    
    STC:
    
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 20677 W: 4023 L: 3901 D: 12753
    
    LTC:
    
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 12221 W: 2022 L: 1888 D: 8311
    
    Bench: 7911336
    
    Resolves #326

commit 6661a3154152ab448b1dc11d882586976f616f92
Author: mstembera <MissingEmail@email>
Date:   Fri Apr 3 01:16:15 2015 +0800

    Simplification to use only one counter move.
    
    STC http://tests.stockfishchess.org/tests/view/5518dca30ebc5902160ec5d0
    LLR: 2.95 (-2.94,2.94) [-3.50,0.50]
    Total: 18868 W: 3638 L: 3530 D: 11700
    
    LTC http://tests.stockfishchess.org/tests/view/5518f7ed0ebc5902160ec5d4
    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 69767 W: 11019 L: 10973 D: 47775
    
    Extracted from http://tests.stockfishchess.org/tests/view/5511028a0ebc5902160ec40b
    
    Original patch by hxim.  All credit goes to him.
    
    Bench: 7664249
    
    Resolves #320

commit 63500274db9beb08c726c27c45f19a22601a0743
Author: Ajith <achajo@yahoo.co.in>
Date:   Sun Mar 29 07:27:43 2015 +0800

    Give a reduced bonus for threats by hanging pawns
    
    Passed STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 105539 W: 20389 L: 20001 D: 65149
    
    and LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 9629 W: 1577 L: 1432 D: 6620
    
    Bench: 7658627
    
    Resolves #317

commit 1d5eaba5735e24c3afdeb07a5108d7ebf9e3ff57
Author: mbootsector <mbootsector@gmail.com>
Date:   Sat Mar 28 22:09:48 2015 +0000

    Retire follow-up move heuristic
    
    STC: http://tests.stockfishchess.org/tests/view/5501d0f30ebc5902160ec0fd
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 34891 W: 6904 L: 6808 D: 21179
    
    LTC: http://tests.stockfishchess.org/tests/view/550328540ebc5902160ec133
    LLR: 3.10 (-2.94,2.94) [-3.00,1.00]
    Total: 182653 W: 29866 L: 29993 D: 122794
    
    Bench: 8396161
    
    Resolves #310

commit ac8e6ff000d3d990ae07297ec60e33a9cfb513b1
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Sat Mar 28 21:15:49 2015 +0000

    Use CounterMoveHistory when calculating LMR for cut nodes
    
    If the sum of CounterMoveHistory heuristic and History heuristic is below zero,
    then reduce an extra ply in cut nodes
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,6.00]
    Total: 6479 W: 1099 L: 967 D: 4413
    
    Bench: 7773299
    
    Resolves #315

commit 50182f11004334177ceeebb93d4b7eadb67aadb9
Author: joergoster <osterj165@googlemail.com>
Date:   Wed Mar 25 07:38:32 2015 +0800

    Tuned values for the pawn piece square table
    
    Quick measure at very fast tc:
    ELO: 4.77 +-2.2 (95%) LOS: 100.0%
    Total: 40124 W: 8711 L: 8160 D: 23253
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 52284 W: 8880 L: 8559 D: 34845
    
    Bench: 8865736
    
    Resolves #311

commit e51965aa57ddc50d04016e3622da49cf9f8e6238
Author: VoyagerOne <excelgeek@gmail.com>
Date:   Tue Mar 24 23:00:31 2015 +0000

    Introduce a new counter move history penalty
    
    Extra penalty for TT move in previous ply when it gets refuted
    
    STC:
    
    LLR: 2.94 (-2.94,2.94) [-1.50,4.50]
    Total: 31303 W: 6216 L: 6025 D: 19062
    
    LTC:
    
    LLR: 2.97 (-2.94,2.94) [0.00,6.00]
    Total: 6950 W: 1189 L: 1054 D: 4707
    
    Bench: 8191926
    
    Resolves #309

commit 966bc477af9eae9be63b08111a76e8306263e4a3
Author: joergoster <osterj165@googlemail.com>
Date:   Fri Mar 20 08:08:21 2015 +0800

    Tuned mobility with another SPSA run
    
    Further improved mobility values after another SPSA session, 50k
    iterations.
    
    Elo measure at very fast 9+0.05":
    ELO: 3.40 +-2.2 (95%) LOS: 99.9%
    Total: 40000 W: 8434 L: 8042 D: 23524
    
    and LTC SPRT[0, 4]:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 11052 W: 1874 L: 1687 D: 7491
    
    Bench: 8226843
    
    Resolves #301

commit a4b98a052e2cadfb15984f0937c8131e18c663b2
Author: joergoster <osterj165@googlemail.com>
Date:   Sat Mar 14 21:35:52 2015 +0000

    New values for Mobility and Outposts.
    
    Both are the result of a SPSA tuning session with a custom book, 50k iterations each.
    
    After an additional tuning session of the mobility values, tuning the delta values, with following result.
    
    40k games at 9+0.05:
    ELO: 4.13 +-2.2 (95%) LOS: 100.0%
    Total: 40000 W: 8581 L: 8106 D: 23313
    
    and LTC
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 36518 W: 6049 L: 5782 D: 24687
    
    Bench: 8567402
    
    Resolves #284

commit 13c11f40480ec97316bd4da3a53787cc871037ea
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Thu Mar 12 07:29:57 2015 +0000

    Introduce Counter Move History tables
    
    Introduce a counter move history table which additionally is indexed by the last move's piece and target square.
    For quiet move ordering use now the sum of standard and counter move history table.
    
    STC:
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 4747 W: 1005 L: 885 D: 2857
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 5726 W: 1001 L: 872 D: 3853
    
    Because of reported low NPS on multi core test
    STC (7 threads):
    ELO: 7.26 +-3.3 (95%) LOS: 100.0%
    Total: 14937 W: 2710 L: 2398 D: 9829
    
    Bench: 7725341
    
    Resolves #282

commit 9369f4963d9376820cb5ca4bad66b86e67b0a010
Author: Stéphane Nicolet <cassio@free.fr>
Date:   Sun Mar 1 00:58:32 2015 +0800

    Raise penalty for knight attacked by pawn
    
    Raise a bit the penalty for knight attacked by pawn.
    
    STC:
    LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
    Total: 27744 W: 5563 L: 5380 D: 16801
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 87571 W: 14747 L: 14314 D: 58510
    
    Bench: 8285241
    
    Resolves #270

commit fce799294c124a096b15539bb863788ec3a68cf6
Author: Alain SAVARD <support@multicim.com>
Date:   Fri Feb 27 01:50:35 2015 +0800

    Apex Pawns
    
    Pawns which are supported already have a bonus. Apex are pawns which are
    supported twice.
    This patch gives an additional 50% bonus for them.
    
    STC
    LLR: 2.96 (-2.94,2.94) [-1.50,4.50]
    Total: 6549 W: 1333 L: 1209 D: 4007
    
    LTC
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 18002 W: 3037 L: 2850 D: 12115
    
    Bench: 8069601
    
    Resolves #267

commit e2226cbb20342bc23ed42cfe538b4e3ca3697291
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Thu Feb 19 14:14:20 2015 +0100

    Use only 'level' as late join metric
    
    It seems other metric are useless, this allow us
    to simplify the code and to prune useless stuff.
    
    STC 20K games 4 threads
    ELO: -0.76 +-2.8 (95%) LOS: 29.9%
    Total: 20000 W: 3477 L: 3521 D: 13002
    
    STC 10K games 16 threads
    ELO: 1.36 +-3.9 (95%) LOS: 75.0%
    Total: 10000 W: 1690 L: 1651 D: 6659
    
    bench: 8253813

commit 2f465927363e3e753dfb65d67f9b126afc34f4fa
Author: snicolet <cassio@free.fr>
Date:   Fri Feb 20 19:56:57 2015 +0000

    Mobile phalanxes
    
    Try to create mobile phalanxes
    
    STC:
    LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
    Total: 52393 W: 10912 L: 10656 D: 30825
    
    LTC:
    LLR: 2.96 (-2.94,2.94) [0.00,6.00]
    Total: 30398 W: 5315 L: 5063 D: 20020
    
    Bench: 8253813
    
    Resolves #261

commit 6656ed8904ccf0e20321f9929f2d13fbb7b9223d
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Tue Feb 17 08:23:35 2015 +0100

    Simplify attackUnits formula
    
    Use '/ 8' instead of '* 31 / 256'
    
    Passed STC
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 55077 W: 10999 L: 10940 D: 33138
    
    And LTC
    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 14751 W: 2530 L: 2400 D: 9821
    
    bench: 7911944

commit a8f9c7a790883d2d31e108cd2739aefcfa5d919e
Author: snicolet <cassio@free.fr>
Date:   Fri Feb 13 21:33:00 2015 +0000

    Small bonus for all safe pawn pushes
    
    Pawn flexibility: add a small bonus for all safe pawn pushes
    
    STC:
    LLR: 2.70 (-2.94,2.94) [-1.50,4.50]
    Total: 18233 W: 3705 L: 3557 D: 10971
    
    LTC:
    LLR: 2.97 (-2.94,2.94) [0.00,6.00]
    Total: 17684 W: 3042 L: 2854 D: 11788
    
    Bench: 7369224
    
    Resolves #253

commit e118570038f2d9b668b445fe6d31df94151a717b
Author: Joona Kiiski <zamar@meripeto.(none)>
Date:   Sun Feb 8 19:20:39 2015 +0000

    Pawn Center Bind Bonus
    
    Bonus for two pawns controlling the same central square
    
    STC:
    
    LLR: 3.14 (-2.94,2.94) [-1.50,4.50]
    Total: 15974 W: 3291 L: 3133 D: 9550
    
    LTC:
    
    LLR: 3.24 (-2.94,2.94) [0.00,6.00]
    Total: 10449 W: 1837 L: 1674 D: 6938
    
    Idea from Lyudmil Tsvetkov.
    
    Bench: 7699138
    
    Resolves #248

commit 18b08096399c0e316baa1999f8cc6ce56bc7f616
Author: Stefan Geschwentner <stgeschwentner@gmail.com>
Date:   Tue Feb 3 11:16:50 2015 +0800

    Add bonus for pawn attack threats
    
    Latent pawn attacks: Add a bonus to safe pawn pushes which attacks an
    enemy piece.  Based on an idea of Lyudmil Tsvetkov.
    
    STC:
    LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
    Total: 7925 W: 1666 L: 1537 D: 4722
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,6.00]
    Total: 40109 W: 6841 L: 6546 D: 26722
    
    Bench: 7696257
    
    Resolves #240

commit ddccb5355cabb7d1a9bf2c0fe3c51b3da0234260
Author: NicklasPersson <nipe0008@student.umu.se>
Date:   Tue Feb 3 04:00:52 2015 +0800

    Improved King Safety values
    
    From an SPSA-session on king safety.
    
    STC:
    ELO: 3.21 +-2.1 (95%) LOS: 99.8%
    Total: 40000 W: 8181 L: 7812 D: 24007
    
    LTC:
    LLR: 2.95 (-2.94,2.94) [0.00,4.00]
    Total: 47765 W: 8091 L: 7785 D: 31889
    
    Bench: 8589262
    
    Resolves #241

commit 7837fb2aca6db425e5f7237f5cc714412fc0140d
Author: NicklasPersson <nipe0008@student.umu.se>
Date:   Wed Jan 28 21:00:09 2015 +0000

    King safety tuning with values obtained by SPSA.
    
    Part I:
    
    LTC:
    
    LLR: 2.96 (-2.94,2.94) [0.00,4.00]
    Total: 11529 W: 2075 L: 1882 D: 7572
    
    Part II:
    
    LTC:
    
    ELO: 2.07 +-2.1 (95%) LOS: 97.3%
    Total: 34859 W: 5967 L: 5759 D: 23133
    
    Bench: 7374604
    
    Resolves #228

commit f53aea45e3230239d358d4d35357c9ee6bf6fb54
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Sun Jan 18 08:05:05 2015 +0100

    Add syzygy support
    
    bench: 8080602

commit 3c07603dac03f0da20194097cf4eb1a396fea60d
Author: Marco Costalba <mcostalba@gmail.com>
Date:   Sun Jan 18 08:00:50 2015 +0100

    Import C++11 branch
    
    Import C++11 branch from:
    
    https://github.com/mcostalba/Stockfish/tree/c++11
    
    The version imported is teh last one as of today:
    https://github.com/mcostalba/Stockfish/commit/6670e93e50a7a4e739ac2ac8b6026ffa3a12150a
    
    Branch is fully equivalent with master but syzygy
    tablebases that are missing (but will be added with
    next commit).
    
    bench: 8080602

lucasart · Post by **lucasart** » Sun Jan 17, 2016 10:12 am

Actually there is one idea worth mentionning: Counter Moves History. It was introduced by Stefan Geschwenter, and proved to be worth quite a bit of elo, as it was later fine tuned, and used in various places (thanks to VoyagerOne who managed to get quite a bit of elo out of this CMH).

As far as I know, this idea did not exist in the "litterature", and is unique to SF. Although, I suppose every top engine has now copied it.

Sven · Post by **Sven** » Sun Jan 17, 2016 11:06 am

I suggest to remove email addresses from the list above.

Michael Sherwin · Post by **Michael Sherwin** » Sun Jan 17, 2016 11:57 am

lucasart wrote:Actually there is one idea worth mentionning: Counter Moves History. It was introduced by Stefan Geschwenter, and proved to be worth quite a bit of elo, as it was later fine tuned, and used in various places (thanks to VoyagerOne who managed to get quite a bit of elo out of this CMH).

As far as I know, this idea did not exist in the "litterature", and is unique to SF. Although, I suppose every top engine has now copied it.

Has been in RomiChess since 2005!

Code: Select all

    case MOVEKILL:
      h->phase = ADDMOVES;
      m.m = moveKill[piece[board[(h-1)->ts]].fig][(h-1)->fs][(h-1)->ts].m;
      if(wtm ? wPieces & setBit[m.fs] : bPieces & setBit[m.fs]) {
        id = board[m.fs];
        if(piece[id].typ == m.typ) {
          if(h->moves[id] & setBit[m.ts]) {
            h->moves[id] ^= setBit[m.ts];
            h->node->m = m.m;
            (h+1)->t = h->node + 1;
            return TRUE;
          }   
        }  
      }

stegemma · Post by **stegemma** » Sun Jan 17, 2016 12:15 pm

Anybody knows if there is a mathematical limit to ELO, in a limited set of players where only one of them grows in strength?

Evert · Post by **Evert** » Sun Jan 17, 2016 12:33 pm

stegemma wrote:Anybody knows if there is a mathematical limit to ELO, in a limited set of players where only one of them grows in strength?

The winning rate of the strongest player grows to 1 asymptotically as its rating approaches infinity (or, more accurately, its rating difference compared to the other players in the pool).

Other than that, no. At least not with the standard Elo models (based on logistic or normal distributions). Of course the winning rate becomes 1 for all practical purposes long before then...

clumma · Post by **clumma** » Sun Jan 17, 2016 8:40 pm

stegemma wrote:Anybody knows if there is a mathematical limit to ELO, in a limited set of players where only one of them grows in strength?

This should probably be a separate thread, but Regan's research suggests that perfect chess corresponds to a FIDE Elo of 3600. He got that result with Rybka and it would be interesting to recompute it with Komodo or SF, but in any case I'd wager it's less than 4000.

-Carl

clumma · Post by **clumma** » Sun Jan 17, 2016 9:24 pm

Thanks for your reply, Lucas. The move to lazy SMP is interesting, and did occur in October. I found these recent threads, which I will read
http://www.talkchess.com/forum/viewtopic.php?t=57572
http://www.talkchess.com/forum/viewtopic.php?t=55352

However, if I'm reading Pohl's site right, his tests are all single-core
http://spcc.beepworld.de/
so lazy SMP probably doesn't explain the two October bumps on his graph.

-Carl

MikeB · Post by **MikeB** » Sun Jan 17, 2016 9:27 pm

clumma wrote:I'm always curious what might be learned from Stockfish's progress. Is it just accumulation of many small improvements, or are some changes more important than others?

This graph by Stefan Pohl makes Elo progress from SF6 to SF7 look non uniform, with a large bump in October

Does anyone know which changes these were?

-Carl

I am fairly certain over the last 7 months or so, since I have been following it, this was the largest single patch worth 8 Elo, . Most seem to be 2 to 3 ELO . They come in spurts , a week or more goes by their may no patches ELO gains. One week you might have 3 or 4 committed the same week with 10 ELO or so. Note: All ELO gains are measured in self testing , which tend to exaggerate the real ELO gain, but they are gains nonetheless.

Very impressed with the approach that they have taken, they have many contributors , 3 or 4 senior programmers (I'm not 100% sure what is the exact protocol - this is the way its appears to me) who review and approve all changes on a collaborative basis, especially given that is it's 100% volunteer and that it is totally 100% transparent. The code is shared with the public as soon as it approved. Second to Bob Hyatt for sharing his code for the last 25+ years, the development and opened source of Fruit , followed by Glaurung and now Stockfish is the primary reason why we now have engines that are far superior to the top GMs. Even if you take a top engine from the 90's and run it on today's hardware, it would not be far superior or perhaps even superior to a top GM. The difference is the source and all those who made their engine open source shared a part in that.

I hope it continues - these are good times for those who enjoy chess engines.

Stockfish 7 progress

Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress

Re: Stockfish 7 progress