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Author SHA1 Message Date
Sergei Ivanov
ad8b78ad52 Fix cycle detection in presence of repetitions
In master search() may incorrectly return a draw score in the following
corner case: there was a 2-fold repetition during the game, and the
current position can be reached by a move from a repeated one. This case
is treated as an upcoming 3-fold repetition, which it is not.

Here is a testcase demonstrating the issue (note that the moves
after FEN are required). The input:

  position fen 8/8/8/8/8/8/p7/2k4K b - - 0 1 moves c1b1 h1g1 b1c1 g1h1 c1b1 h1g1 b1a1 g1h1
  go movetime 1000

produces the output:

  [...]
  info depth 127 seldepth 2 multipv 1 score cp 0 [...]
  bestmove a1b1

saying that the game will be drawn by repetion. However the other possible
move for black, Kb2, avoids repetitions and wins. The patch fixes this behavior.
In particular it finds mate in 10 in the above position.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 10604 W: 2390 L: 2247 D: 5967
http://tests.stockfishchess.org/tests/view/5cb373e00ebc5925cf0167bf

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19620 W: 3308 L: 3185 D: 13127
http://tests.stockfishchess.org/tests/view/5cb3822f0ebc5925cf016b2d

Bench is not changed since it does not test positions with history of moves.

Bench: 3184182
2019-05-09 15:39:57 +02:00
Stefan Geschwentner
368f976fb6 Less LMR at root
Do no LMR for the first four moves if at root node.

STC:
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 19686 W: 4524 L: 4261 D: 10901
http://tests.stockfishchess.org/tests/view/5cd3577b0ebc5925cf04a089

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 88335 W: 15193 L: 14766 D: 58376
http://tests.stockfishchess.org/tests/view/5cd35e600ebc5925cf04a1c3

Bench: 3184182
2019-05-09 15:25:39 +02:00
Stefan Geschwentner
b6d11028bb LMR for captures not cracking alpha
Enable LMR for a capture/promotion move which does not seem
to have a good chance to fail high according to static eval
and value of captured piece.

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 40477 W: 9158 L: 8792 D: 22527
http://tests.stockfishchess.org/tests/view/5cceedc60ebc5925cf04174f

LTC:
LLR: 2.94 (-2.94,2.94) [0.00,3.50]
Total: 21926 W: 3873 L: 3634 D: 14419
http://tests.stockfishchess.org/tests/view/5ccf04310ebc5925cf041ab0

Bench: 3644175
2019-05-05 23:18:17 +02:00
VoyagerOne
aba906b734 Stat Score reset at rootNode - Bench: 3393330 (#2124)
At rootNode reset great great grandchildren stat score i.e (ss + 4)->statScore = 0

STC: (yellow)
LLR: -2.96 (-2.94,2.94) [0.50,4.50]
Total: 256079 W: 57423 L: 56315 D: 142341
http://tests.stockfishchess.org/tests/view/5ccb0c420ebc5925cf03a6a5

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 61550 W: 10611 L: 10260 D: 40679
http://tests.stockfishchess.org/tests/view/5ccbf9d00ebc5925cf03c487

Bench: 3393330
2019-05-04 13:41:53 +02:00
Marco Costalba
4e72e2a964 Assorted trivial cleanups 4/2019
No functional change.
2019-05-02 19:30:26 +02:00
Joost VandeVondele
5c4002aa82 Simplified shuffle extension version (#2121)
only the extension part of the shuffle patch is sufficient to
pass [0,3.5] bounds at VLTC as shown by two more tests.

http://tests.stockfishchess.org/tests/view/5cc168bc0ebc5925cf02bda8
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 120684 W: 17875 L: 17400 D: 85409

http://tests.stockfishchess.org/tests/view/5cc14d510ebc5925cf02bcb5
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 68415 W: 10250 L: 9905 D: 48260

this patch proposes to simplify back to this basic and easier to
understand version. In case there is a need to run a [-3, 1] VLTC on
this one, it can be done, but it is resource intensive, and not needed
IMO.

Bench: 3388643
2019-05-02 19:22:29 +02:00
Joost VandeVondele
7ede1ed071 Allow for address sanitizer. (#2119)
Properly allow for sanitize=address (-fsanitize=address) as an argument to the Makefile.

No functional change
2019-04-27 20:47:06 +02:00
Marco Costalba
e4c1f8759d Fix bench number of previous patch
bench: 3388643
2019-04-27 11:37:51 +02:00
Michael Chaly
9a11a29194 Include bishop protection in king Danger evaluation. #2118
Same idea as fisherman's knight protection.

passed STC
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 17133 W: 3952 L: 3701 D: 9480 
http://tests.stockfishchess.org/tests/view/5cc3550b0ebc5925cf02dada

passed LTC
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 37316 W: 6470 L: 6188 D: 24658 
http://tests.stockfishchess.org/tests/view/5cc3721d0ebc5925cf02dc90

Looking at this 2 ideas being recent clean elo gainers I have a feeling that we can add also rook and queen protection bonuses or overall move this stuff in pieces loop in the same way as we do pieces attacking bonuses on their kingring... :) Thx fisherman for original idea.

Bench 3429173
2019-04-27 11:31:55 +02:00
MJZ1977
e89bc30fdc Shuffle detection #2108
Bench: 3402947
2019-04-27 11:25:23 +02:00
Joost VandeVondele
6373fd56e9 Remove useless initializations (#2115)
Removes two unneeded inits, they are always set before their use later on.

No functional change.
2019-04-24 19:51:57 +02:00
protonspring
a858b5a84e Remove DistanceRing #2107
Remove the DistanceRing array. This reduces the
memory footprint by about 4kb.

http://tests.stockfishchess.org/tests/view/5cba35350ebc5925cf020d7f
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 101421 W: 22491 L: 22528 D: 56402

No functional change.
2019-04-20 08:34:14 +02:00
Joost VandeVondele
bdeb01dec0 Remove capping in reduction (#2110)
Saves two std::min.

Bench is unchanged to high depth, but in principle this is a functional change so tested both STC and LTC.

passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78193 W: 17220 L: 17210 D: 43763
http://tests.stockfishchess.org/tests/view/5cb789540ebc5925cf01b90b

passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 93846 W: 15964 L: 15962 D: 61920
http://tests.stockfishchess.org/tests/view/5cb8066d0ebc5925cf01c72b

Bench: 3402947
2019-04-19 17:33:26 +02:00
Joost VandeVondele
f21b503982 Simplify distance (#2109)
Only called with Squares as argument, so remove unused variants.

As this is just syntax changes, only verified bench at high depth.

No functional change.
2019-04-18 16:53:52 +02:00
protonspring
c4fc00ec49 Remove Movepick::move (#2085)
The "move" class variable is Movepick is removed (removes some abstraction) which saves a few assignment operations, and the effects of "filter" is limited to the current move (movePtr). The resulting code is a bit more verbose, but it is also more clear what is going on. This version is NOT tested, but is substantially similar to:

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 29191 W: 6474 L: 6367 D: 16350
http://tests.stockfishchess.org/tests/view/5ca7aab50ebc5925cf006e50

This is a non-functional simplification.
2019-04-17 21:13:39 +02:00
protonspring
3b46df546d Move pawnsOnSquares to Position (#2100)
We can remove the values in Pawns if we just use the piece arrays in Position. This reduces the size of a pawn entry. This simplification passed individually, and in concert with ps_passedcount100 (removes passedCount storage in pawns.).

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 19957 W: 4529 L: 4404 D: 11024
http://tests.stockfishchess.org/tests/view/5cb3c2d00ebc5925cf016f0d

Combo STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17368 W: 3925 L: 3795 D: 9648
http://tests.stockfishchess.org/tests/view/5cb3d3510ebc5925cf01709a

This is a non-functional simplification.
2019-04-16 23:10:53 +02:00
protonspring
76777b663a Calculate passedCount real-time #2099
This is a non-functional simplification which removes the passedCount variable in pawns.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 27982 W: 6227 L: 6118 D: 15637
http://tests.stockfishchess.org/tests/view/5cb3cdd30ebc5925cf017025

Combo STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17368 W: 3925 L: 3795 D: 9648
http://tests.stockfishchess.org/tests/view/5cb3d3510ebc5925cf01709a

Non functional test.
2019-04-16 16:12:47 +02:00
protonspring
eb07775583 Remove semiopenFiles in pawns and simplify space #2102
This is a functional simplification.

    1. semiopenFiles is removed in pawns and uses the piece arrays in position instead.

    2. popcount is removed in space calculations and uses pawn piece count instead.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33327 W: 7423 L: 7324 D: 18580
http://tests.stockfishchess.org/tests/view/5cb4be090ebc5925cf018511

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 10173 W: 1774 L: 1636 D: 6763
http://tests.stockfishchess.org/tests/view/5cb4c5920ebc5925cf018696

bench 3402947
2019-04-16 16:09:36 +02:00
Joost VandeVondele
1594d15922 Remove two useless assignments (#2093)
These variables are initialized before their use in the movepicker loop.

passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 138732 W: 30727 L: 30838 D: 77167
http://tests.stockfishchess.org/tests/view/5cb07af40ebc5925cf012c32

No functional change.
2019-04-13 17:17:47 +02:00
Joost VandeVondele
42d271f23c Give penalty for all early quiets of prev. ply
passed STC:
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 32884 W: 7283 L: 7184 D: 18417
http://tests.stockfishchess.org/tests/view/5cacb1b20ebc5925cf00ce97

passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 22869 W: 3920 L: 3803 D: 15146
http://tests.stockfishchess.org/tests/view/5cacbd760ebc5925cf00cfce

Bench: 3723099
2019-04-13 17:15:15 +02:00
protonspring
a2cdb6e5d2 Simplify Connected Pawn Scoring #2090
This is a functional simplification that simplifies
connected scoring of pawns.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37472 W: 8318 L: 8228 D: 20926
http://tests.stockfishchess.org/tests/view/5cae74ef0ebc5925cf00f8a5

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43035 W: 7366 L: 7281 D: 28388
http://tests.stockfishchess.org/tests/view/5caea3b50ebc5925cf00fe1e

Bench: 3470173
2019-04-13 16:58:41 +02:00
Marco Costalba
5928cb2b30 Revert "Shuffle detection #2064"
It causes a serious regression hanging a simple fixed
depth search. Reproducible with:

position fen q1B5/1P1q4/8/8/8/6R1/8/1K1k4 w - - 0 1
go depth 13

The reason is a search tree explosion due to:

if (... && depth < 3 * ONE_PLY)
      extension = ONE_PLY;

This is very dangerous code by itself because triggers **at the leafs**
and in the above position keeps extending endlessly. In normal games
time deadline makes the search to stop sooner or later, but in fixed
seacrch we just hang possibly for a very long time. This is not acceptable
because 'go depth 13' shall not be a surprise for any position.

This patch reverts commit 76f1807baa.
and fixes the issue https://github.com/official-stockfish/Stockfish/issues/2091

Bench: 3243738
2019-04-12 13:48:04 +02:00
miguel-l
5b5687d76e Extend dangerous passed pawn moves (#2089)
Introduce a new search extension when pushing an advanced passed pawn is
also suggested by the first killer move. There have been previous tests
which have similar ideas, mostly about pawn pushes, but it seems to be
overkill to extend too many moves. My idea is to limit the extension to
when a move happens to be noteworthy in some other way as well, such as
in this case, when it is also a killer move.

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 19027 W: 4326 L: 4067 D: 10634
http://tests.stockfishchess.org/tests/view/5cac2cde0ebc5925cf00c36d

LTC:
LLR: 2.94 (-2.94,2.94) [0.00,3.50]
Total: 93390 W: 15995 L: 15555 D: 61840
http://tests.stockfishchess.org/tests/view/5cac42270ebc5925cf00c4b9

For future tests, it looks like this will interact heavily with passed
pawn evaluation. It may be good to try more variants of some of the more
promising evaluations tests/tweaks.

Bench: 3666092
2019-04-10 19:35:47 +02:00
protonspring
ec49e676a7 Simplify castlingPath (#2088)
Instead of looping through kfrom,kto, rfrom, rto, we can use BetweenBB. This is less lines of code and it is more clear what castlingPath actually is. Personal benchmarks are all over the place. However, this code is only executed when loading a position, so performance doesn't seem that relevant.

No functional change.
2019-04-10 19:33:57 +02:00
31m059
ab4b94e173 Raise kingDanger threshold and adjust constant term #2087
The kingDanger term is intended to give a penalty which increases rapidly in the middlegame but less so in the endgame. To this end, the middlegame component is quadratic, and the endgame component is linear. However, this produces unintended consequences for relatively small values of kingDanger: the endgame penalty will exceed the middlegame penalty. This remains true up to kingDanger = 256 (a S(16, 16) penalty), so some of these inaccurate penalties are actually rather large.

In this patch, we increase the threshold for applying the kingDanger penalty to eliminate some of this unintended behavior. This was very nearly, but not quite, sufficient to pass on its own. The patch was finally successful by integrating a second kingDanger tweak by @Vizvezdenec, increasing the kingDanger constant term slightly and improving both STC and LTC performance.

Where do we go from here? I propose that in the future, any attempts to tune kingDanger coefficients should also consider tuning the kingDanger threshold. The evidence shows clearly that it should not be automatically taken to be zero.

Special thanks to @Vizvezdenec for the kingDanger constant tweak. Thanks also to all the approvers and CPU donors who made this possible!

STC:
LLR: -2.96 (-2.94,2.94) [0.00,4.00]
Total: 141225 W: 31239 L: 30846 D: 79140
http://tests.stockfishchess.org/tests/view/5cabbdb20ebc5925cf00b86c

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 30708 W: 5296 L: 5043 D: 20369
http://tests.stockfishchess.org/tests/view/5cabff760ebc5925cf00c22d

Bench: 3445945
2019-04-09 19:35:17 +02:00
protonspring
f98c77413b Remove BetweenBB Array #2076
Non functional change.
2019-04-09 13:46:12 +02:00
Marco Costalba
8fa6273ff6
Fix sed for OS X (#2080)
The sed command is a bit different in Mac OS X (why not!).

The ‘-i’ option required a parameter to tell what extension to add for the 
backup file. To fix it, just add extension for backup file, for example ‘.bak’ 

Fix broken Trevis CI test

No functional change.
2019-04-06 12:43:41 +02:00
erbsenzaehler
49a1fdd3fe Make ONE_PLY value independent again
And a Trevis CI test to catch future issues.

No functional change.
2019-04-06 11:15:17 +02:00
Marco Costalba
fdd799bc16
Fix a missing assignment in previous commit
While reformatting the patch, I got wrong a statement and converted it badly.
2019-04-06 02:03:15 +02:00
xoto10
1982fe25f8 Use average bestMoveChanges across all threads #2072
The current update only by main thread depends on the luck of
whether main thread sees any/many changes to the best move or not.
It then makes large, lumpy changes to the time to be
used (1x, 2x, 3x, etc) depending on that sample of 1.
Use the average across all threads to get a more reliable
number with a smoother distribution.

STC @ 5+0.05 th 4 :
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 51899 W: 11446 L: 11029 D: 29424
http://tests.stockfishchess.org/tests/view/5ca32ff20ebc5925cf0016fb

STC @ 5+0.05 th 8 :
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 13851 W: 2843 L: 2620 D: 8388
http://tests.stockfishchess.org/tests/view/5ca35ae00ebc5925cf001adb

LTC @ 20+0.2 th 8 :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 48527 W: 7941 L: 7635 D: 32951
http://tests.stockfishchess.org/tests/view/5ca37cb70ebc5925cf001cec

Further work:
Similar changes might be possible for the fallingEval and timeReduction calculations (and elsewhere?), using either the min, average or max values across all threads.

Bench 3506898
2019-04-05 20:37:16 +02:00
Moez Jellouli
0f63b35120 Remove pureStaticEval #2069
Remove pureStaticEval variable and keep only one
static evaluation (ss->staticEval).

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 64617 W: 14348 L: 14312 D: 35957 Elo -0.24
http://tests.stockfishchess.org/tests/view/5c9e1ad70ebc5925cfffc106

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 82200 W: 13703 L: 13680 D: 54817 Elo -0.24
http://tests.stockfishchess.org/tests/view/5c9e4efd0ebc5925cfffc68b

Bench : 3506898
2019-04-04 09:40:34 +02:00
Moez Jellouli
aa0166fba6 Add attacked by 2 pawns to attackedBy2 (#2074)
Add squares attacked by 2 pawns to the attackedBy2 array

STC :
LLR: -2.95 (-2.94,2.94) [0.50,4.50]
Total: 132722 W: 29583 L: 29090 D: 74049
http://tests.stockfishchess.org/tests/view/5ca231ba0ebc5925cf000794

LTC :
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 94589 W: 16161 L: 15718 D: 62710
http://tests.stockfishchess.org/tests/view/5ca25d180ebc5925cf000ba4

Bench: 3337864
2019-04-04 08:49:35 +02:00
Marco Costalba
82ad9ce9cf
Assorted trivial cleanups 3/2019 (#2030)
No functional change.
2019-03-31 11:47:36 +02:00
protonspring
95ba7f78d5 Use simple array for Pawns Connected bonus #2061
Simplification which removes the pawns connected array.
Instead of storing the values in an array, the values are
calculated real-time. This is about 1.6% faster on my machines.

Performance:
master ave nps: 159,248,672
patch ave nps: 161,905,592

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 20363 W: 4579 L: 4455 D: 11329
http://tests.stockfishchess.org/tests/view/5c9925ba0ebc5925cfff79a6

Non functional change.
2019-03-31 11:28:48 +02:00
Moez Jellouli
76f1807baa Shuffle detection #2064
Shuffle detection procedure :

Shuffling positions are detected if

    the last 36 moves are reversible (rule50_count() > 36),
    the position have been already in the TT,
    there is a still a pawn on the board (to avoid special endings like KBN vs K).

The position is then judged as a draw.

An extension is realized if we already made 14 successive reversible moves in PV to accelerate the detection of the eventual draw.

To go further : we can still improve the idea. The length of the tests need a lot of ressources.

    the limit of 36 is logic but must be checked again for special zugzwang positions,
    this limit can be decreased in special positions,
    the limit of 14 moves for extension has not been tuned.

STC
LLR: -2.94 (-2.94,2.94) [0.50,4.50]
Total: 32595 W: 7273 L: 7275 D: 18047 Elo +0.43
http://tests.stockfishchess.org/tests/view/5c90aa330ebc5925cfff1768

LTC
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 51249 W: 8807 L: 8486 D: 33956 Elo +1.85
http://tests.stockfishchess.org/tests/view/5c90b2450ebc5925cfff1800

VLTC
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 137974 W: 20503 L: 19983 D: 97488 Elo +1.05
http://tests.stockfishchess.org/tests/view/5c9243a90ebc5925cfff2a93

Bench: 3548313
2019-03-31 10:51:08 +02:00
protonspring
c858990377 Replace std::mins/max with clamp function (#2062)
Adding a clamp function makes some of these range limitations a bit prettier and removes some #include's.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28117 W: 6300 L: 6191 D: 15626
http://tests.stockfishchess.org/tests/view/5c9aa1df0ebc5925cfff8fcc

Non functional change.
2019-03-31 10:48:27 +02:00
Joost VandeVondele
d1f76ebcd8 Remove duplication. (#2068)
always use the implementation of gives_check in position, no need to
hand-inline part of the implementation in search.

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 57895 W: 12632 L: 12582 D: 32681
http://tests.stockfishchess.org/tests/view/5c9eaa4b0ebc5925cfffc9e3

No functional change.
2019-03-31 10:44:55 +02:00
protonspring
796d0ad70e Accessor for SquareBB #2067
This is a non-functional code style change.

If we add an accessor function for SquareBB we can consolidate all of the asserts. This is also a bit cleaner because all SquareBB accesses go through this method making future changes easier to manage.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 63406 W: 14084 L: 14045 D: 35277
http://tests.stockfishchess.org/tests/view/5c9ea6100ebc5925cfffc9af

No functional change.
2019-03-31 10:43:20 +02:00
protonspring
7133598a98 Simplify pawn asymmetry (remove use of semiopen files). (#2054)
This is a functional simplification.

To me, the exclusive OR of semiopenFiles here is quite convoluted. Looks like it can be removed.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43885 W: 9731 L: 9653 D: 24501
http://tests.stockfishchess.org/tests/view/5c9041680ebc5925cfff10ea

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 68437 W: 11577 L: 11533 D: 45327
http://tests.stockfishchess.org/tests/view/5c9101740ebc5925cfff1cbf

bench 3575627
2019-03-24 17:41:25 +01:00
Joost VandeVondele
2f11c03bbf Remove unneeded condition. (#2057)
This is covered by the line just before. If we would like to protect
against the piece value of e.g. a N == B, this could be done by an
assert, no need to do this at runtime.

No functional change.
2019-03-24 17:40:29 +01:00
protonspring
ea5505821d Simplify Passed Pawns (#2058)
This is a non-functional simplification/speedup.

The truth-table for popcount(support) >= popcount(lever) - 1 is:
------------------lever
------------------0-------1---------2
support--0------X-------X---------0
-----------1------X-------X---------X
-----------2------X-------X---------X

Thus, it is functionally equivalent to just do: support || !more_than_one(lever) which removes the expensive popcounts and the -1.

Result of 20 runs:
base (...h_master.exe) = 1451680 +/- 8202
test (./stockfish ) = 1454781 +/- 8604
diff = +3101 +/- 931

STC
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 35424 W: 7768 L: 7674 D: 19982
Http://tests.stockfishchess.org/tests/view/5c970f170ebc5925cfff5e28

No functional change.
2019-03-24 17:37:38 +01:00
xoto10
d320de7619 Remove !extension check #2045
While looking at pruning using see_ge() (which is very valuable)
it became apparent that the !extension test is not adding any
value - simplify it away.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 56843 W: 12621 L: 12569 D: 31653
http://tests.stockfishchess.org/tests/view/5c8588cb0ebc5925cffe77f4

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 78622 W: 13223 L: 13195 D: 52204
http://tests.stockfishchess.org/tests/view/5c8611cc0ebc5925cffe7f86

Further work could be to optimize the remaining see_ge() test. The idea of less pruning at higher depths is valuable, but perhaps the test (-PawnValueEg * depth) can be improved.

Bench: 3188688
2019-03-20 14:57:34 +01:00
CoffeeOne
66818f2e85 Skip skipping thread scheme (#1972)
Several simplification tests (all with the bounds [-3,1]) were run:
5+0.05 8 threads, failed very quickly:
http://tests.stockfishchess.org/tests/view/5c439a020ebc5902bb5d3970

20+0.2 8 threads, also failed, but needed a lot more games:
http://tests.stockfishchess.org/tests/view/5c44b1b70ebc5902bb5d4e34

60+0.6 8 threads passed:
http://tests.stockfishchess.org/tests/view/5c48bfe40ebc5902bca15325

60+0.6 4 threads passed:
http://tests.stockfishchess.org/tests/view/5c4b71a00ebc593af5d49904

No functional change.
2019-03-20 14:50:41 +01:00
Marco Costalba
bad18bccb6
Increase thread stack for OS X (#2035)
On OS X threads other than the main thread are created with a reduced stack
size of 512KB by default, this is dangerously low for deep searches, so
adjust it to TH_STACK_SIZE. The implementation calls pthread_create() with
proper stack size parameter.

Verified for no regression at STC enabling the patch on all platforms where
pthread is supported.

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 50873 W: 9768 L: 9700 D: 31405

No functional change.
2019-03-12 08:35:10 +01:00
protonspring
b8efa0daac Remove popcount16() (#2038)
This is a non-functional simplification / code-style change.

This popcount16 method does nothing but initialize the PopCnt16 arrays.

This can be done in a single bitset line, which is less lines and more clear. Performance for this code is moot.

No functional change.
2019-03-10 10:53:39 +01:00
xoto10
acc47e8b79 Simplify failedLow away #1986
FailedLow doesn't seem to add any value so remove it.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43915 W: 9682 L: 9604 D: 24629
http://tests.stockfishchess.org/tests/view/5c5339770ebc592fc7baef74

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 58515 W: 9670 L: 9609 D: 39236
http://tests.stockfishchess.org/tests/view/5c53cc840ebc592fc7baf6c1

Ideas for further work:

    Tune the values in the revised fallingEval calculation
    Consider adding a term using delta, e.g. c * (delta - 20) as an indicator of eval instability

Bench: 3318033
2019-03-10 10:47:42 +01:00
Marco Costalba
4d0981fef3 Revert "Allowing singular extension in mate positions"
It was causing an assert: value > -VALUE_INFINITE
under some conditions.

See https://github.com/official-stockfish/Stockfish/issues/2036

Bench: 3318033
2019-03-09 13:28:11 +01:00
protonspring
1aab5b4b05 Remove FutilityMoveCounts array. (#2024)
This is a functional simplification that removes the FutilityMoveCounts array with a simple equation using only ints.

LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 14175 W: 3123 L: 2987 D: 8065

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 9900 W: 1735 L: 1597 D: 6568

Bench: 3380343
2019-03-05 20:48:29 +01:00
protonspring
714e857c24 Shrink Reductions[] array to one dimension
This is a non-functional patch which shrinks the reductions array.
This saves about 8Kb of memory.

The only slow part of master's reductions array is the calculation
of the log values, so using a separate array for those values and
calculating the rest real-time appears to be just as fast as master.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 63245 W: 13906 L: 13866 D: 35473
http://tests.stockfishchess.org/tests/view/5c7b571f0ebc5925cffdc104

No funcional change.
2019-03-05 19:02:04 +01:00
SFisGOD
58bbbd176b Pawn value tweak
STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 47166 W: 10664 L: 10311 D: 26191
http://tests.stockfishchess.org/tests/view/5c7dfc370ebc5925cffdf830

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 35439 W: 6034 L: 5767 D: 23638
http://tests.stockfishchess.org/tests/view/5c7e41020ebc5925cffdfe9b

Bench: 3470519
2019-03-05 14:54:25 +01:00