Stefan Geschwentner [Wed, 25 Jul 2018 23:28:37 +0000 (01:28 +0200)]
Rank threats on pinned pawns
Add for pinned pawns half of the standard rank based threat bonus.
STC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 44010 W: 9987 L: 9635 D: 24388
http://tests.stockfishchess.org/tests/view/
5b58aa780ebc5902bdb88c7a
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 29475 W: 5089 L: 4847 D: 19539
http://tests.stockfishchess.org/tests/view/
5b58b56c0ebc5902bdb88f37
Closes https://github.com/official-stockfish/Stockfish/pull/1701
Bench:
4503866
Stéphane Nicolet [Wed, 25 Jul 2018 16:31:02 +0000 (18:31 +0200)]
Code clean-up
This patch implements some idea by Alain Savard and Mike Whiteley taken from the perpertual renaming/reformatting thread.
This is a pure code cleaning patch (so no change in functionality), but I use it as a pretext to correct the bogus bench number that I introduced in the previous commit.
Bench:
4413383
Stefan Geschwentner [Wed, 25 Jul 2018 16:01:47 +0000 (18:01 +0200)]
Tweak stat bonus
Increase stat bonus by 1/32 and adjust the divisor of main and capture
history tables to 10692.
STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 28437 W: 6444 L: 6166 D: 15827
http://tests.stockfishchess.org/tests/view/
5b579b4d0ebc5902bdb87139
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 111204 W: 19160 L: 18644 D: 73400
http://tests.stockfishchess.org/tests/view/
5b57a7c60ebc5902bdb872d3
Closes https://github.com/official-stockfish/Stockfish/pull/1698
Bench:
4778882
VoyagerOne [Wed, 25 Jul 2018 11:49:35 +0000 (07:49 -0400)]
CounterMove History Pruning Tweak
STC: (Yellow)
LLR: -2.96 (-2.94,2.94) [0.00,5.00]
Total: 40124 W: 8817 L: 8751 D: 22556
http://tests.stockfishchess.org/tests/view/
5b5690180ebc5902bdb85c8a
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 21599 W: 3811 L: 3599 D: 14189
http://tests.stockfishchess.org/tests/view/
5b5757010ebc5902bdb86b1f
Closes https://github.com/official-stockfish/Stockfish/pull/1697
Bench:
4794161
Stefan Geschwentner [Tue, 24 Jul 2018 10:16:49 +0000 (12:16 +0200)]
Revert "Tweak reductions formula: 0.88 * depth + 0.12"
This patch reverts the recent commit called "Tweak reductions formula, etc."
The decisions for the revert decision were as follows:
1) The original commit called "Tweak reductions formula: 0.88 * depth + 0.12"
showed bad scaling at in a Very Long Time Control (VLTC) test:
VLTC (180+1.8):
LLR: -1.59 (-2.94,2.94) [0.00,5.00]
Total: 14968 W: 2247 L: 2257 D: 10464
http://tests.stockfishchess.org/tests/view/
5b559ffa0ebc5902bdb84f36
2) So there was a suspicion that the original fast passing LTC test which lead
us to accept the patch may have been a statistical accident, so we organized
a match against the previous master at LTC to get an Elo estimate for the
patch:
LTC match:
ELO: -1.83 +-2.1 (95%) LOS: 4.3%
Total: 36018 W: 6018 L: 6208 D: 23792
http://tests.stockfishchess.org/tests/view/
5b55f8110ebc5902bdb8526f
3) Based on these results, we ran a simplification test with [-3..1] bounds
for the revert at LTC:
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 41501 W: 7107 L: 7020 D: 27374
http://tests.stockfishchess.org/tests/view/
5b5738670ebc5902bdb86932
4) So we revert.
Bench:
4491691
double-beep [Mon, 23 Jul 2018 20:06:24 +0000 (22:06 +0200)]
Slight decrease of overload value
Set overload value to S(13,6)
STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 27606 W: 6371 L: 6094 D: 15141
http://tests.stockfishchess.org/tests/view/
5b5455840ebc5902bdb82425
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 112435 W: 19442 L: 18921 D: 74072
http://tests.stockfishchess.org/tests/view/
5b546d4a0ebc5902bdb82741
Closes https://github.com/official-stockfish/Stockfish/pull/1694
Bench:
4937000
Stefan Geschwentner [Mon, 23 Jul 2018 07:16:14 +0000 (09:16 +0200)]
Tweak reductions formula: 0.88 * depth + 0.12
Replace the depth part in the reduction formula for higher depths
with a slower growing linear function. So for depth > 3 less reductions
are used.
What we can try next:
- move the break point to even higher depths
- tweak the slope for lower and higher depth
- even possibly use a further higher depth threshold for a another
slower growing function
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 25317 W: 5763 L: 5505 D: 14049
http://tests.stockfishchess.org/tests/view/
5b54f9f70ebc5902bdb840ed
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 7451 W: 1320 L: 1167 D: 4964
http://tests.stockfishchess.org/tests/view/
5b54feeb0ebc5902bdb84244
Closes https://github.com/official-stockfish/Stockfish/pull/1692
Bench:
4617359
Goodkov Vasiliy Aleksandrovich [Sun, 22 Jul 2018 22:02:37 +0000 (00:02 +0200)]
Simplify condition for ThreatByRook
Remove stronglyProtected Queen for ThreatByRook. Idea is that in the
current master the SliderOnQueen bonus and the see_ge() function do
something similar as ThreatByRook for Queen, so this patch removes
some redundancy, in that sense.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 21878 W: 4939 L: 4818 D: 12121
http://tests.stockfishchess.org/tests/view/
5b53a83b0ebc5902bdb815d1
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 35307 W: 5979 L: 5882 D: 23446
http://tests.stockfishchess.org/tests/view/
5b53b60b0ebc5902bdb8174c
Close https://github.com/official-stockfish/Stockfish/pull/1690
Bench:
4834554
protonspring [Sat, 21 Jul 2018 06:17:27 +0000 (00:17 -0600)]
simplified forward ranks.
This is a non-functional simplification. We change replaces an 'OR'
and a lookup (rank_bb(ksq)) with a bitwise ~. This is fewer operations
and is probably faster.
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 25441 W: 5689 L: 5575 D: 14177
http://tests.stockfishchess.org/tests/view/
5b52d05a0ebc5902bdb8010e
LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 26904 W: 4664 L: 4553 D: 17687
http://tests.stockfishchess.org/tests/view/
5b543df70ebc5902bdb8212d
No functional change.
Marco Costalba [Sat, 21 Jul 2018 08:30:22 +0000 (10:30 +0200)]
Slight tidy up in endgame machinery
No functional change.
Stefan Geschwentner [Sat, 21 Jul 2018 02:21:54 +0000 (04:21 +0200)]
Non functional LMR rewrite.
Alain SAVARD [Fri, 20 Jul 2018 23:57:45 +0000 (19:57 -0400)]
Simplify the "overload" condition
This is a follow-up of the previous pull request (#1686) by Miguel.
We simplify the "Overload" bonus condition by re-using the "weak"
variable, which captures well the essence of the overload condition.
This may also be a small speed optimization because the weak variable
is in a register at this point of the code.
http://tests.stockfishchess.org/tests/view/
5b527b440ebc5902bdb7f7db
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 10925 W: 2517 L: 2374 D: 6034
http://tests.stockfishchess.org/tests/view/
5b527f930ebc5902bdb7f883
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 15569 W: 2697 L: 2568 D: 10304
Closes https://github.com/official-stockfish/Stockfish/pull/1687
Bench:
5010472
Miguel Lahoz [Thu, 19 Jul 2018 11:18:30 +0000 (19:18 +0800)]
Remove connectivity.
There seems to be some strange interaction between Overload and Connectivity.
Overload encourages us to not have too many defended and attacked pieces,
as this may expose us to various tactics. This feels somewhat like it is in
conflict with Connectivity, where pieces are defended preemptively.
Here I take the "pick one or the other" approach and just remove connectivity,
while strengthening the effect of Overload to compensate. The reasoning is that
if we defend our pieces preemptively, then it does get attacked, we want to do
something about it so we don't get penalized by Overload. On the other
hand, if it doesn't get attacked, then there's no need to defend it.
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 27734 W: 6174 L: 6064 D: 15496
http://tests.stockfishchess.org/tests/view/
5b5073bd0ebc5902bdb7ba5c
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 51606 W: 8897 L: 8827 D: 33882
http://tests.stockfishchess.org/tests/view/
5b50aa900ebc5902bdb7bf29
Bench:
4658006
Stefan Geschwentner [Thu, 19 Jul 2018 16:26:05 +0000 (18:26 +0200)]
Better check evasion move sorting
Use in addition the counter move history table for sorting quiet
check evasion moves in main and quiecence search. Also rename
"contHistory" to "continuationHistory" while there.
STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 73284 W: 16433 L: 15938 D: 40913
http://tests.stockfishchess.org/tests/view/
5b4f526e0ebc5902bdb7a401
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 12135 W: 2171 L: 1997 D: 7967
http://tests.stockfishchess.org/tests/view/
5b4fc0ef0ebc5902bdb7ae0e
Closes https://github.com/official-stockfish/Stockfish/pull/1685
Bench
4817583
Miguel Lahoz [Mon, 16 Jul 2018 16:51:43 +0000 (00:51 +0800)]
Use single value for KingProtector.
After some recent big tuning session, the values for King Protector were
simplified to only be used on minor pieces. This patch tries to further
simplify by just using a single value, since current S(6,5) and S(5,6)
are close to each other. The value S(6,6) ended up passing, although
S(5,5) was also tried and failed STC.
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 14261 W: 3288 L: 3151 D: 7822
http://tests.stockfishchess.org/tests/view/
5b4ccdf50ebc5902bdb77f65
LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 19606 W: 3396 L: 3273 D: 12937
http://tests.stockfishchess.org/tests/view/
5b4ce4280ebc5902bdb7803b
Bench:
5448998
ElbertoOne [Wed, 18 Jul 2018 06:36:23 +0000 (08:36 +0200)]
Simplify Overload condition
Extend the bonus for Overload to cases where our side
has more than one attacker to a non pawn piece.
Based on an idea by Bryan in the forum. For instance,
now black gets the overload bonus in this position:
8/5R1k/6pb/p6p/P1N4P/1Pp5/2K3P1/2N4r b - - 6 46
because two black pieces are attacking the knight on c1
that is defended only by the king.
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 57446 W: 12762 L: 12711 D: 31973
http://tests.stockfishchess.org/tests/view/
5b4ca9970ebc5902bdb77a88
LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 42113 W: 7295 L: 7209 D: 27609
http://tests.stockfishchess.org/tests/view/
5b4ccea00ebc5902bdb77f69
Bench:
4667263
DU-jdto [Mon, 16 Jul 2018 20:53:50 +0000 (06:53 +1000)]
Minor code style tweaks
No functional change.
ianfab [Sun, 15 Jul 2018 12:30:59 +0000 (14:30 +0200)]
Minor whitespace formatting changes
No functional change.
Gian-Carlo Pascutto [Tue, 17 Jul 2018 21:13:12 +0000 (23:13 +0200)]
Allow Position::init() to be called multiple times.
For the rationale to allow this, see commit
a66c73deef420104e74b6645ee60e20b37fd8549
This was broken when cuckoo hashing was added, and
subtly broke (for example) lichess' Android application,
thus illustrating the original judgement was sound.
No functional change.
protonspring [Sat, 14 Jul 2018 06:26:57 +0000 (08:26 +0200)]
Remove rank limitation for MinorBehindPawn
This is a functional simplification. It seems like the rank restriction
for MinorBehindPawn can be removed.
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 61195 W: 13404 L: 13360 D: 34431
http://tests.stockfishchess.org/tests/view/
5b47e6f00ebc5978f4be3fc0
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 31701 W: 5367 L: 5264 D: 21070
http://tests.stockfishchess.org/tests/view/
5b48a2cb0ebc5978f4be4769
Bench:
4938702
candirufish [Sat, 14 Jul 2018 06:08:32 +0000 (08:08 +0200)]
Tuned Values after 2 million spsa games
Various king and pawn eval values tuned after 2 million games. Rounding
slightly adjusted.
LTC: http://tests.stockfishchess.org/tests/view/
5b477a260ebc5978f4be3ed4
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 32783 W: 5852 L: 5588 D: 21343
STC: http://tests.stockfishchess.org/tests/view/
5b472d420ebc5978f4be3e4d
LLR: 3.23 (-2.94,2.94) [0.00,4.00]
Total: 44380 W: 10201 L: 9841 D: 24338
I think I reached the limit of the fishtest framework. It frequently
crashed at 2 million games already. The small values also moved a lot
throughout the entire tuning session though with smaller margin. The
passed danger and close enemies values seems the most sensitive (changing
close enemies alone to 6 failed before but now it passes), whether or not
they are close to optimal I don't know, but it seems some parameters are
also correlated to others.
Closes https://github.com/official-stockfish/Stockfish/pull/1670
bench:
5103722
Joost VandeVondele [Thu, 5 Jul 2018 16:33:18 +0000 (18:33 +0200)]
Remove offset in thread redistribution scheme.
doesn't have a benefit.
passed STC (8 threads):
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 19574 W: 4028 L: 3904 D: 11642
http://tests.stockfishchess.org/tests/view/
5b3e48950ebc5902b9fff080
passed LTC (8 threads):
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 21293 W: 3626 L: 3506 D: 14161
http://tests.stockfishchess.org/tests/view/
5b3eefd60ebc5902b9fffa81
Closes https://github.com/official-stockfish/Stockfish/pull/1667
No functional change single threaded.
31m059 [Thu, 5 Jul 2018 02:18:52 +0000 (22:18 -0400)]
Simplify ThreatByKing to be a single Score.
In the current master, ThreatByKing is an array of two Scores, one for
when we have a single attack and one for when we have many. The latter
case is very rarely called during bench and was recently given a strange
negative value during a tuning run, as pointed out by @candirufish on
commit
efd4ca2. Here, we simplify away this second case entirely, and
increase the remaining ThreatByKing to compensate.
Although I derived the parameter tweak independently, with the goal of
preserving the same average bonus, I later noticed that a very similar
Score had already been derived by an ongoing SPSA tuning session.
I therefore recognize @candirufish for first discovering these values.
I would also like to thank @Rocky640 for valuable feedback that pointed
me in the direction of ThreatByKing.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7677 W: 1772 L: 1623 D: 4282
http://tests.stockfishchess.org/tests/view/
5b3db0320ebc5902b9ffe97a
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 108031 W: 18329 L: 18350 D: 71352
http://tests.stockfishchess.org/tests/view/
5b3dbf4b0ebc5902b9ffe9db
Closes https://github.com/official-stockfish/Stockfish/pull/1666
Bench:
4678861
VoyagerOne [Tue, 3 Jul 2018 23:11:54 +0000 (01:11 +0200)]
Capture Stat Tweak
Penalize capture moves that fail to create a cutoff even at quiet move cutoff.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 19004 W: 4284 L: 4059 D: 10661
http://tests.stockfishchess.org/tests/view/
5b3a7d4d0ebc5902b9ffb6ea
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 23100 W: 3981 L: 3765 D: 15354
http://tests.stockfishchess.org/tests/view/
5b3aa4550ebc5902b9ffb8cf
Closes https://github.com/official-stockfish/Stockfish/pull/1664
Bench:
5232010
Joost VandeVondele [Tue, 3 Jul 2018 22:58:16 +0000 (00:58 +0200)]
Simplify saving a TT entry.
Avoid passing TT.generation() to TTEntry::save() at every call,
moving the implementation of TTEntry::save from tt.h to tt.cpp.
tested for no regression:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 53787 W: 11948 L: 11890 D: 29949
http://tests.stockfishchess.org/tests/view/
5b2ff37f0ebc5902b2e582fe
Closes https://github.com/official-stockfish/Stockfish/pull/1662
No functional change.
Joost VandeVondele [Tue, 3 Jul 2018 22:48:20 +0000 (00:48 +0200)]
Reduce scope of variables
Small cleanup TranspositionTable:clear().
Closes https://github.com/official-stockfish/Stockfish/pull/1659
No functional change.
Ondrej Mosnáček [Sat, 9 Jun 2018 11:45:49 +0000 (13:45 +0200)]
Move PSQ score to Position
This patch simplifies Position::do_move() by moving the PSQ score from
StateInfo to Position and updating it inside the put/remove/move_piece
functions.
The downside is that there is now slightly more computation done in
Position::undo_move(), but the fishtest results are Elo neutral.
Passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78820 W: 15775 L: 15760 D: 47285
http://tests.stockfishchess.org/tests/view/
5b1cd1d00ebc5902ab9c64ab
Passed LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32966 W: 5716 L: 5615 D: 21635
http://tests.stockfishchess.org/tests/view/
5b31e1230ebc5902b2e5a833
Closes https://github.com/official-stockfish/Stockfish/pull/1647
No functional change.
protonspring [Sun, 17 Jun 2018 02:26:25 +0000 (20:26 -0600)]
Remove make_bitboard()
In current master, the function make_bitboard() does nothing apart from
helping initialize the SquareBB[] array. This seems like an unnecessary
abstraction layer.
The advantage of make_bitboard() is we can define a bitboard, in a simple
and general way, not only from a single square but also from a list of
squares. It is more elegant, faster and readable than combining multiple
SquareBB explicitly, but the last complex use case in evaluation was
simplified away a few months ago.
If make_bitboard() becomes useful again to define complicated bitboards,
it will be easy enough to reintroduce it using this pull request as
an implementation reference.
No functional change.
joergoster [Sun, 24 Jun 2018 15:07:38 +0000 (17:07 +0200)]
Simplify KingProtector penalty.
Recent tuning results implied this penalty is more important for knights
and bishops, and almost negligible for rooks and queen.
Passed as simplification both
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 20873 W: 4592 L: 4469 D: 11812
http://tests.stockfishchess.org/tests/view/
5b2fb4d00ebc5902b2e57e84
and LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 46069 W: 7949 L: 7870 D: 30250
http://tests.stockfishchess.org/tests/view/
5b2fcc4b0ebc5902b2e580c5
Closes https://github.com/official-stockfish/Stockfish/pull/1660
Bench:
5487679
Alain SAVARD [Sun, 24 Jun 2018 22:06:13 +0000 (18:06 -0400)]
Simplify HinderPassedPawn bonus
Make sure each piece is not scored more than once as a passed pawn "hinderer",
by scoring only the blockers along the passed pawn path. Inspired by TCEC Game 29.
Passed STC as a simplification
http://tests.stockfishchess.org/tests/view/
5b3016d00ebc5902b2e58552
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 75388 W: 16656 L: 16641 D: 42091
Passed LTC as a simplification
http://tests.stockfishchess.org/tests/view/
5b302ed90ebc5902b2e587fc
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 49157 W: 8460 L: 8386 D: 32311
Current master was also counting the number of attacks along a passed pawn path,
which might be misleading:
a) a defender might be counted many times for the same pawn path. For example a
White rook on a1 attacking a black pawn on a7 would score the bonus * 6 but
would be probably better placed on a8
b) a defender might be counted on different pawn paths and might be overloaded. For
example a Ke4 or Qe4 against pawns on d6 and f6 would score the bonus * 6.
Counting each blocker or attacker only once is more complicated, and does not help
either: http://tests.stockfishchess.org/tests/view/
5b2ff1cb0ebc5902b2e582b2
After this small simplification, there might be ways to increase the HinderPassedPawn
penalty.
Closes https://github.com/official-stockfish/Stockfish/pull/1661
Bench:
4520519
candirufish [Sat, 23 Jun 2018 06:57:05 +0000 (08:57 +0200)]
Another set of tuned values after one million games
Another set of tuned values, obtained by a long session of one million games.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 15810 W: 3687 L: 3458 D: 8665
http://tests.stockfishchess.org/tests/view/
5b2d32f60ebc5902b2e55d9e
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 102118 W: 18146 L: 17651 D: 66321
http://tests.stockfishchess.org/tests/view/
5b2d372c0ebc5902b2e55e0a
Closes https://github.com/official-stockfish/Stockfish/pull/1658
Bench:
4557946
Stéphane Nicolet [Thu, 21 Jun 2018 23:28:02 +0000 (01:28 +0200)]
Increase outflanking weight to 12
Give more incentive to king activity in the endgame by increasing the weight
of the "outflanking" variable from 8 to 12 in the function evaluate_initiative().
Finished yellow after 133102 games at STC:
LLR: -3.07 (-2.94,2.94) [0.00,4.00]
Total: 133102 W: 29535 L: 29179 D: 74388
http://tests.stockfishchess.org/tests/view/
5b2b63fe0ebc5902b2e54475
Passed LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 28027 W: 4918 L: 4672 D: 18437
http://tests.stockfishchess.org/tests/view/
5b2ba39e0ebc5902b2e54a64
Closes https://github.com/official-stockfish/Stockfish/pull/1657
Bench:
4721753
candirufish [Thu, 21 Jun 2018 08:20:31 +0000 (10:20 +0200)]
Tuned values after 505k games
Various king and pawn tuned eval values after 505k 60 sec 600 nodes time
SPSA games. Adjusted passed rank and file values to be symmetrical.
Passed LTC (after passed rank/file adjustment):
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 37906 W: 6953 L: 6668 D: 24285
http://tests.stockfishchess.org/tests/view/
5b2790960ebc5902b8d17ba1
A previous, very similar version with raw tuned values passed STC and LTC:
STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 39515 W: 9227 L: 8900 D: 21388
http://tests.stockfishchess.org/tests/view/
5b277e3e0ebc5902b8d17ac9
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 14618 W: 2743 L: 2537 D: 9338
http://tests.stockfishchess.org/tests/view/
5b2785020ebc5902b8d17b98
Closes https://github.com/official-stockfish/Stockfish/pull/1654
bench:
4777396
Michael An [Thu, 21 Jun 2018 01:05:27 +0000 (21:05 -0400)]
Fix GCC 8 cast warnings
Silences the following warnings when compiling with GCC 8.
The fix is to use an intermediate pointer to anonymous function:
```
misc.cpp: In function 'int WinProcGroup::get_group(size_t)':
misc.cpp:241:77: warning: cast between incompatible function types from 'FARPROC' {aka 'long long int (*)()'} to 'fun1_t' {aka 'bool (*)(_LOGICAL_PROCESSOR_RELATIONSHIP, _SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX*, long unsigned int*)'} [-Wcast-function-type]
auto fun1 = (fun1_t)GetProcAddress(k32, "GetLogicalProcessorInformationEx");
^
misc.cpp: In function 'void WinProcGroup::bindThisThread(size_t)':
misc.cpp:309:71: warning: cast between incompatible function types from 'FARPROC' {aka 'long long int (*)()'} to 'fun2_t' {aka 'bool (*)(short unsigned int, _GROUP_AFFINITY*)'} [-Wcast-function-type]
auto fun2 = (fun2_t)GetProcAddress(k32, "GetNumaNodeProcessorMaskEx");
^
misc.cpp:310:67: warning: cast between incompatible function types from 'FARPROC' {aka 'long long int (*)()'} to 'fun3_t' {aka 'bool (*)(void*, const _GROUP_AFFINITY*, _GROUP_AFFINITY*)'} [-Wcast-function-type]
auto fun3 = (fun3_t)GetProcAddress(k32, "SetThreadGroupAffinity");
^
```
No functional change.
mstembera [Tue, 12 Jun 2018 22:20:38 +0000 (15:20 -0700)]
Fix MSVC error
Compiling the current master with MSVC gives the following error:
```
search.cpp(956): error C2660: 'operator *': function does not take 1 arguments
types.h(303): note: see declaration of 'operator *'
```
This was introduced in commit:
https://github.com/official-stockfish/Stockfish/commit/
88de112b84a5285c2afb3e075a05c2ab8ad3fd33
We use a suggestion by @vondele to fix the error, thanks!
No functional change.
Stefano80 [Wed, 20 Jun 2018 03:24:24 +0000 (05:24 +0200)]
Slight simplification in scale factor computation
[STC](http://tests.stockfishchess.org/tests/view/
5b2614000ebc5902b8d17193)
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 17733 W: 3996 L: 3866 D: 9871
[LTC](http://tests.stockfishchess.org/tests/view/
5b264d0f0ebc5902b8d17206)
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 55524 W: 9535 L: 9471 D: 36518
Use pawn count scaling also for opposite bishops endings with additional material, with a slope of 2 instead of 7. This simplifies slightly the code.
This PR is a functionally equivalent refactoring of the version which was submitted.
Four versions tried, 2 passed both STC and LTC. I picked the one which seemed more promising at LTC.
Slope 4 passed STC (-0.54 Elo), LTC not attempted
Slope 3 passed STC (+2.51 Elo), LTC (-0.44 Elo)
Slope 2 passed STC (+2.09 Elo), LTC (+0.04 Elo)
Slope 1 passed STC (+0.90 Elo), failed LTC (-3.40 Elo)
Bench:
4761613
DU-jdto [Wed, 13 Jun 2018 05:22:52 +0000 (15:22 +1000)]
Remove lmrDepth restriction on quiet see pruning
And tweak the threshold value. With this threshold and the current piece
values, this permits see pruning on quiets to be done up to an lmrDepth
of 9 (beyond that the threshold is below -QueenValueMg and see_ge will
pass unconditionally).
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 110316 W: 24612 L: 24667 D: 61037
http://tests.stockfishchess.org/tests/view/
5b20aa760ebc5902ab9c9c1d
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 17352 W: 2968 L: 2842 D: 11542
http://tests.stockfishchess.org/tests/view/
5b20cf1e0ebc5902ab9c9fb6
Closes https://github.com/official-stockfish/Stockfish/pull/1651
Bench:
5069074
Joost VandeVondele [Tue, 12 Jun 2018 05:32:21 +0000 (07:32 +0200)]
Remove depth condition for pruning captures.
The SEE condition alone is sufficient.
passed STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 109863 W: 24339 L: 24392 D: 61132
http://tests.stockfishchess.org/tests/view/
5b1f5b000ebc5902ab9c8668
passed LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 23390 W: 4020 L: 3903 D: 15467
http://tests.stockfishchess.org/tests/view/
5b1f94b40ebc5902ab9c8b5e
Closes https://github.com/official-stockfish/Stockfish/pull/1648
Bench:
4834747
protonspring [Mon, 11 Jun 2018 08:17:03 +0000 (10:17 +0200)]
Optimize an expression in endgame.cpp
I believe using foward_file_bb() here is fewer instructions.
a) Fewer instructions and probably more clear (debatable).
b) Possible that a lookup is slower than a few local operations, but the
forward_file_bb table is probably used often enough that it is always
cached.
Passed
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 21004 W: 4263 L: 4141 D: 12600
http://tests.stockfishchess.org/tests/view/
5b1cad830ebc5902ab9c6239
Closes https://github.com/official-stockfish/Stockfish/pull/1644
No functional change.
candirufish [Sun, 10 Jun 2018 08:53:05 +0000 (01:53 -0700)]
Simplify capture pruning margin formula
Using just `PawnValueEg * depth` as Capture Prune Margin. There was a bunch
of patches that passed recently regarding captures, maybe this part of the
master code redundant? The patch was tested as a simplification:
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 20833 W: 4218 L: 4096 D: 12519
http://tests.stockfishchess.org/tests/view/
5b1cf2100ebc5902ab9c6651
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 27050 W: 3975 L: 3864 D: 19211
http://tests.stockfishchess.org/tests/view/
5b1cfdc80ebc5902ab9c6776
Closes https://github.com/official-stockfish/Stockfish/pull/1643
Bench:
4980482
Stefan Geschwentner [Mon, 11 Jun 2018 06:39:55 +0000 (08:39 +0200)]
Optimize contempt value (21)
After several tests it seems best to increase contempt from 12 to 21. This does
not regress against contempt=0 and gives a gain of around 7-8 elo against SF 7
in comparison to current default contempt.
STC: Test for non-regression contempt=21 against contempt=0
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 71250 W: 13956 L: 13926 D: 43368
http://tests.stockfishchess.org/tests/view/
5b19a58d0ebc5902ab9c3bfa
STC: Test contempt 21 against SF 7
ELO: 190.06 +-2.8 (95%) LOS: 100.0%
Total: 40000 W: 22608 L: 2676 D: 14716
http://tests.stockfishchess.org/tests/view/
5b19a6520ebc5902ab9c3c0e
STC: Test master against SF 7 for comparison
ELO: 182.95 +-2.7 (95%) LOS: 100.0%
Total: 40000 W: 21905 L: 2595 D: 15500
http://tests.stockfishchess.org/tests/view/
5b16f5bc0ebc59214346d5ca
LTC: Test for non-regression contempt=21 against contempt=0
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 47666 W: 6914 L: 6832 D: 33920
http://tests.stockfishchess.org/tests/view/
5b1a170b0ebc5902ab9c3fde
LTC: Test contempt 21 against SF 7
ELO: 203.92 +-2.6 (95%) LOS: 100.0%
Total: 40000 W: 22447 L: 1340 D: 16213
http://tests.stockfishchess.org/tests/view/
5b1a174b0ebc5902ab9c3fe1
LTC: Test master against SF 7 for comparison
ELO: 196.08 +-2.6 (95%) LOS: 100.0%
Total: 40000 W: 21639 L: 1191 D: 17170
http://tests.stockfishchess.org/tests/view/
5b1a17e40ebc5902ab9c3fe4
Closes https://github.com/official-stockfish/Stockfish/pull/1646
Bench:
4786912
Joost VandeVondele [Mon, 11 Jun 2018 07:46:05 +0000 (09:46 +0200)]
Remove failedLow from the mainThread struct
failedLow is in fact a local variable in Thread::search().
Also clean some spaces and tabs in code.
No functional change.
candirufish [Wed, 6 Jun 2018 08:13:08 +0000 (10:13 +0200)]
Quiet move soft fail high bonus
Extra bonus for quiet move creating a huge soft fail high (triggered
in 21% of quiet bestmoves on a normal bench run). Pb00067 original idea
using PawnValueMg.
Passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 138207 W: 28060 L: 27295 D: 82852
http://tests.stockfishchess.org/tests/view/
5b14471b0ebc5902a81689c1
Passe LTC:
LLR: 2.94 (-2.94,2.94) [0.00,5.00]
Total: 157289 W: 23200 L: 22518 D: 111571
http://tests.stockfishchess.org/tests/view/
5b149dde0ebc5902a8b41c5a
bench:
4441320
VoyagerOne [Wed, 6 Jun 2018 00:43:33 +0000 (20:43 -0400)]
Simplify capture bonus
Simplify capture bonus by simply adding ONE_DEPTH instead of being
dependent on BestValue.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 24419 W: 4939 L: 4824 D: 14656
http://tests.stockfishchess.org/tests/view/
5b16b2040ebc5963ba37e2a5
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 44560 W: 6524 L: 6438 D: 31598
http://tests.stockfishchess.org/tests/view/
5b16ccc00ebc59214346d403
Closes https://github.com/official-stockfish/Stockfish/pull/1640
Bench:
4782637
Stéphane Nicolet [Tue, 5 Jun 2018 08:54:51 +0000 (10:54 +0200)]
Call cycle detection before qsearch()
This has the property of raising alpha before calling qsearch(), thus
maybe giving some more cuts during qsearch(). The patch is equivalent
to the use of cycle detection inside qsearch() at depth 0, but is in
fact implemented by re-ordering code inside search(), which explains
the [0..4] bounds in the following tests.
STC (interrupted after 124250 games, with LLR=0.87):
http://tests.stockfishchess.org/tests/view/
5b1500bd0ebc5902a8b420bf
LLR: 0.87 (-2.94,2.94) [0.00,4.00]
Total: 124250 W: 24973 L: 24470 D: 74807
LTC:
http://tests.stockfishchess.org/tests/view/
5b1590eb0ebc5902a84dcd09
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 74234 W: 11098 L: 10733 D: 52403
Closes https://github.com/official-stockfish/Stockfish/pull/1635
Bench:
4326784
Joost VandeVondele [Tue, 5 Jun 2018 16:05:58 +0000 (18:05 +0200)]
Stabilize AppVeyor CI
After a helpful suggestion from AppVeyor support staff, moving the Stockfish
execution from ps to cmd seems to work. Alternative to PR #1624 tested in PR #1637.
No functional change.
Guenther Demetz [Mon, 4 Jun 2018 07:10:30 +0000 (09:10 +0200)]
Remove a superfluous subtrahend
The '- 1' subtrahend was introduced for guarding against null move
search at root, which would be nonsense. But this is actually already
guaranteed by the !PvNode condition. This followed from the discussion
in pull request 1609: https://github.com/official-stockfish/Stockfish/pull/1609
No functional change
VoyagerOne [Sun, 3 Jun 2018 20:46:18 +0000 (16:46 -0400)]
Simplify LMR for captures
Simplify LMR for captures by removing capture's stat score logic for reduction.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37068 W: 7462 L: 7370 D: 22236
http://tests.stockfishchess.org/tests/view/
5b115bc30ebc591af58a6fd2
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 80061 W: 11706 L: 11671 D: 56684
http://tests.stockfishchess.org/tests/view/
5b117f590ebc59033d2d5315
Closes https://github.com/official-stockfish/Stockfish/pull/1631
Bench:
4470519
joergoster [Fri, 1 Jun 2018 20:35:23 +0000 (22:35 +0200)]
Bugfix of Position::has_repeated()
The function Position::has_repeated() is used by Tablebases::root_probe()
to determine whether we can rank all winning moves with the same value, or
if we need to strictly rank by dtz in case the position has already been
repeated once, and we are risking to run into the 50-move rule and thus
losing the win (especially critical in some very complicated endgames).
To check whether the current position or one of the previous positions
after the last zeroing move has already been occured once, we start looking
for a repetition of the current position, and if that is not the case, we
step one position back and repeat the check for that position, and so on.
If you now look at how this was done before the new root ranking patch was
merged two months ago, it seems quite obvious that it is a simple oversight:
https://github.com/official-stockfish/Stockfish/commit/
108f0da4d7f993732aa2e854b8f3fa8ca6d3b46c
More specifically, after we stepped one position back with
```
stc = stc->previous;
```
we now have to start checking for a repetition with
```
StateInfo* stp = stc->previous->previous;
```
and not with
```
StateInfo* stp = st->previous->previous;
```
Closes https://github.com/official-stockfish/Stockfish/pull/1625
No functional change
Stéphane Nicolet [Sun, 3 Jun 2018 07:18:18 +0000 (09:18 +0200)]
Fix overload ambiguity
Fix an error when compiling current master with MSVC due to the
ambiguity of which operator* overload was intended (reported by
Jarrod Torriero).
No functional change.
pb00068 [Sat, 2 Jun 2018 16:01:11 +0000 (18:01 +0200)]
Extra bonus for capture creating a huge fail high
STC:
http://tests.stockfishchess.org/tests/view/
5b114f3d0ebc596e9e0881f6
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 13007 W: 2730 L: 2541 D: 7736
LTC:
http://tests.stockfishchess.org/tests/view/
5b1176740ebc59033d2d52c6
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 15594 W: 2417 L: 2239 D: 10938
See https://github.com/official-stockfish/Stockfish/pull/1627
Bench:
4790240
Stéphane Nicolet [Sat, 2 Jun 2018 15:41:37 +0000 (17:41 +0200)]
Fix comments, rename variables
Thanks everybody for the various hints in the perpetual renaming thread:
https://github.com/official-stockfish/Stockfish/issues/1426
No functional change
Joost VandeVondele [Sat, 2 Jun 2018 15:02:23 +0000 (17:02 +0200)]
Reallocate TT on threadpool resize.
Makes sure the potential benefit of first touch does not depend on
the order of the UCI commands Threads and Hash, by reallocating the
hash if a Threads is issued. The cost is zeroing the TT once more
than needed. In case the prefered order (first Threads than Hash)
is employed, this amounts to zeroing the default sized TT (16Mb),
which is essentially instantaneous.
Follow up for https://github.com/official-stockfish/Stockfish/pull/1601
where additional data and discussion is available.
Closes https://github.com/official-stockfish/Stockfish/pull/1620
No functional change.
Joost VandeVondele [Thu, 24 May 2018 11:31:40 +0000 (13:31 +0200)]
Simplify depth reduction in IID.
Use a constant reduction instead of a depth dependent reduction.
passed STC:
http://tests.stockfishchess.org/tests/view/
5b06eb600ebc5914abc12ba8
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 58086 W: 11710 L: 11657 D: 34719
passed LTC:
http://tests.stockfishchess.org/tests/view/
5b07b25e0ebc5914abc12c6d
LLR: 3.09 (-2.94,2.94) [-3.00,1.00]
Total: 110414 W: 16217 L: 16219 D: 77978
Bench:
4521056
Rodrigo Exterckötter Tjäder [Mon, 14 May 2018 17:52:21 +0000 (14:52 -0300)]
Use threads to clear the TT faster.
Stockfish currently takes a while to clear the TT when using larger hash sizes.
On one machine with 128 GB hash it takes about 50 seconds with a single thread,
allowing it to use all allocated cores brought that time down to 4 seconds on
some Linux systems. The patch was further tested on Windows and refined with
NUMA binding of the hash initializing threads (we refer to pull request #1601
for the complete discussion and the speed measurements).
Closes https://github.com/official-stockfish/Stockfish/pull/1601
No functional change
VoyagerOne [Thu, 24 May 2018 17:05:36 +0000 (19:05 +0200)]
LMR Capture Tweak
Increase capture reduction by comparing opponent's stat score
STC: (Yellow)
LLR: -2.96 (-2.94,2.94) [0.00,5.00]
Total: 92291 W: 18647 L: 18350 D: 55294
http://tests.stockfishchess.org/tests/view/
5b04225e0ebc5914abc1291b
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 20176 W: 3061 L: 2868 D: 14247
http://tests.stockfishchess.org/tests/view/
5b04bb3f0ebc5914abc129a3
How to continue?
• we could try a different value for the capture history threeshold
Closes https://github.com/official-stockfish/Stockfish/pull/1612
Bench:
5167159
protonspring [Thu, 24 May 2018 16:46:38 +0000 (18:46 +0200)]
Simplify BlockedByPawn to one dimension
I was able to get this to pass which reduces BlockedByPawn to one dimension
with NO distance from edge offset.
GOOD) It's more simple and may provide additional clarity for further
simplifications. Facilitates migrating unblocked to one dimension as well.
BAD) If there is indeed a distance component to BlockedStorm (may or may
not be the case), this obfuscates this component into ShelterStrength and
UnblockedStorm. This may be more convoluted. Also, it may be more convenient
to have each of the three arrays (ShelterStrength, BlockedStorm, and UnBlocked)
be the same size.
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 96173 W: 19326 L: 19343 D: 57504
http://tests.stockfishchess.org/tests/view/
5b04544d0ebc5914abc12965
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 49818 W: 7441 L: 7363 D: 35014
http://tests.stockfishchess.org/tests/view/
5b0487d50ebc5914abc12990
Closes https://github.com/official-stockfish/Stockfish/pull/1611
Bench:
5133208
Joost VandeVondele [Thu, 24 May 2018 16:26:21 +0000 (18:26 +0200)]
Correctly prevent recursive verification in nmp.
As discussed with @pb00068, the condition to prevent recursive verification
was not completely correct. This patch corrects that condition, and adds an
assert. In the current implementation, recursive verification needs to be
avoided in order not to break the verification of the move closer to the
root (i.e. to not set thisThread->nmp_min_ply to zero prematurely).
This patch is tested as a bug fix, based on and tested against PR #1609 .
passed STC:
http://tests.stockfishchess.org/tests/view/
5b050f170ebc5914abc129c5
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 7875 W: 1669 L: 1523 D: 4683
passed LTC:
http://tests.stockfishchess.org/tests/view/
5b0513970ebc5914abc129cd
LLR: 3.00 (-2.94,2.94) [-3.00,1.00]
Total: 24048 W: 3525 L: 3407 D: 17116
Bench changes at high depth.
Closes https://github.com/official-stockfish/Stockfish/pull/1610
and https://github.com/official-stockfish/Stockfish/pull/1609
Bench:
4484288
Joost VandeVondele [Tue, 22 May 2018 18:30:58 +0000 (20:30 +0200)]
Simplify color usage in search.
define Color us and use this instead of pos.side_to_move() and nmp_odd. The latter allows to clarify the nmp verification criterion.
Tested for no regression:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 76713 W: 15303 L: 15284 D: 46126
http://tests.stockfishchess.org/tests/view/
5b046a0d0ebc5914abc12971
No functional change.
VoyagerOne [Tue, 22 May 2018 05:21:57 +0000 (07:21 +0200)]
Simply reset StatScore to zero at beta cutoff
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43154 W: 8706 L: 8625 D: 25823
http://tests.stockfishchess.org/tests/view/
5b01a7660ebc5914abc1271d
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 48155 W: 7036 L: 6955 D: 34164
http://tests.stockfishchess.org/tests/view/
5b01b2e50ebc5914abc1272c
Closes https://github.com/official-stockfish/Stockfish/pull/1608
Bench:
4484288
protonspring [Mon, 21 May 2018 07:50:38 +0000 (09:50 +0200)]
Simplify shelter: always do strength and danger
This check of pawns before subtracting danger can be removed.
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 21174 W: 4361 L: 4239 D: 12574
http://tests.stockfishchess.org/tests/view/
5b00b9f90ebc5914abc12680
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 56980 W: 8377 L: 8309 D: 40294
http://tests.stockfishchess.org/tests/view/
5b00ca750ebc5914abc12683
Closes https://github.com/official-stockfish/Stockfish/pull/1607
Bench:
4746692
Stéphane Nicolet [Mon, 21 May 2018 07:37:16 +0000 (09:37 +0200)]
Simplifying away the progressKey
Simplifying away all the progressKey stuff gives exactly the same bench,
without any speed impact. Tested for speed against master with two benches
at depth 22 ran in parallel:
**testedpatch**
Total time (ms) : 92350
Nodes searched :
178962949
Nodes/second :
1937877
**master**
Total time (ms) : 92358
Nodes searched :
178962949
Nodes/second :
1937709
We also tested the patch at STC for no-regression with [-3, 1] bounds:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 57299 W: 11529 L: 11474 D: 34296
http://tests.stockfishchess.org/tests/view/
5b015a1c0ebc5914abc126e5
Closes https://github.com/official-stockfish/Stockfish/pull/1603
No functional change.
mstembera [Wed, 16 May 2018 21:38:13 +0000 (23:38 +0200)]
Fix MSVC errors in tbprobe.cpp
Default template parameters values and recursive functions do not play well
together. Fix for below errors that showed up after updating to latest MSVC.
````
tbprobe.cpp(1156): error C2672:
'search': no matching overloaded function found
tbprobe.cpp(1198): error C2783:
'Tablebases::WDLScore `anonymous-namespace'::search(Position &,Tablebases::ProbeState *)':
could not deduce template argument for 'CheckZeroingMoves'
````
Closes https://github.com/official-stockfish/Stockfish/pull/1594
No functional change.
Tom Truscott [Wed, 16 May 2018 20:47:41 +0000 (22:47 +0200)]
Use cycle detection to bound search value
A position which has a move which draws by repetition, or which could have
been reached from an earlier position in the game tree, is considered to be
at least a draw for the side to move.
Cycle detection algorithm by Marcel van Kervink:
https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf
----------------------------
How does the algorithm work in practice? The algorithm is an efficient
method to detect if the side to move has a drawing move, without doing any
move generation, thus possibly giving a cheap cutoffThe most interesting
conditions are both on line 1195:
```
if ( originalKey == (progressKey ^ stp->key)
|| progressKey == Zobrist::side)
```
This uses the position keys as a sort-of Bloom filter, to avoid the expensive
checks which follow. For "upcoming repetition" consider the opening Nf3 Nf6 Ng1.
The XOR of this position's key with the starting position gives their difference,
which can be used to look up black's repeating move (Ng8). But that look-up is
expensive, so line 1195 checks that the white pieces are on their original squares.
This is the subtlest part of the algorithm, but the basic idea in the above game
is there are 4 positions (starting position and the one after each move). An XOR
of the first pair (startpos and after Nf3) gives a key matching Nf3. An XOR of
the second pair (after Nf6 and after Ng1) gives a key matching the move Ng1. But
since the difference in each pair is the location of the white knight those keys
are "identical" (not quite because while there are 4 keys the the side to move
changed 3 times, so the keys differ by Zobrist::side). The loop containing line
1195 does this pair-wise XOR-ing.
Continuing the example, after line 1195 determines that the white pieces are
back where they started we still need to make sure the changes in the black
pieces represents a legal move. This is done by looking up the "moveKey" to
see if it corresponds to possible move, and that there are no pieces blocking
its way. There is the additional complication that, to match the behavior of
is_draw(), if the repetition is not inside the search tree then there must be
an additional repetition in the game history. Since a position can have more
than one upcoming repetition a simple count does not suffice. So there is a
search loop ending on line 1215.
On the other hand, the "no-progress' is the same thing but offset by 1 ply.
I like the concept but think it currently has minimal or negative benefit,
and I'd be happy to remove it if that would get the patch accepted. This
will not, however, save many lines of code.
-----------------------------
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 36430 W: 7446 L: 7150 D: 21834
http://tests.stockfishchess.org/tests/view/
5afc123f0ebc591fdf408dfc
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 12998 W: 2045 L: 1876 D: 9077
http://tests.stockfishchess.org/tests/view/
5afc2c630ebc591fdf408e0c
How could we continue after the patch:
• The code in search() that checks for cycles has numerous possible variants.
Perhaps the check need could be done in qsearch() too.
• The biggest improvement would be to get "no progress" to be of actual benefit,
and it would be helpful understand why it (probably) isn't. Perhaps there is an
interaction with the transposition table or the (fantastically complex) tree
search. Perhaps this would be hard to fix, but there may be a simple oversight.
Closes https://github.com/official-stockfish/Stockfish/pull/1575
Bench:
4550412
VoyagerOne [Mon, 14 May 2018 04:52:16 +0000 (06:52 +0200)]
Update search.cpp
At PvNodes allow bonus for prior counter move that caused a fail low
for depth 1 and 2. Note : I did a speculative LTC on yellow STC patch
since history stats tend to be highly TC sensitive
STC (Yellow):
LLR: -2.96 (-2.94,2.94) [0.00,5.00]
Total: 64295 W: 13042 L: 12873 D: 38380
http://tests.stockfishchess.org/tests/view/
5af507c80ebc5968e6524153
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 22407 W: 3413 L: 3211 D: 15783
http://tests.stockfishchess.org/tests/view/
5af85dd40ebc591fdf408b87
Also use local variable excludedMove in NMP (marotear)
Bench:
5294316
Stéphane Nicolet [Sun, 13 May 2018 05:20:39 +0000 (07:20 +0200)]
Tweak kingAttackersCount and KingAttackWeights
Use the whole kingRing for pawn attackers instead of only the squares directly
around the king. This tends to give quite a lot more kingAttackersCount, so to
compensate and to avoid raising the king danger too fast we lower the values
in the KingAttackWeights array a little bit.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 51892 W: 10723 L: 10369 D: 30800
http://tests.stockfishchess.org/tests/view/
5af6d4dd0ebc5968e652428e
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 24536 W: 3737 L: 3515 D: 17284
http://tests.stockfishchess.org/tests/view/
5af709890ebc5968e65242ac
Credits to user @xoroshiro for the idea of using the kingRing for pawn attackers.
How to continue? It seems that the KingAttackWeights[] array stores values
which are quite Elo-sensitive, yet they have not been tuned with SPSA recently.
There might be easy Elo points to get there.
Closes https://github.com/official-stockfish/Stockfish/pull/1597
Bench:
5282815
mstembera [Thu, 10 May 2018 20:49:56 +0000 (13:49 -0700)]
Include all blockers in king danger
Simplification: in king danger, include all blockers and not only pinned
pieces, since blockers enemy pieces can result in discovered checks which
are also bad.
STC http://tests.stockfishchess.org/tests/view/
5af35f9f0ebc5968e6523fe9
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 145781 W: 29368 L: 29478 D: 86935
LTC http://tests.stockfishchess.org/tests/view/
5af3cb430ebc5968e652401f
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 76398 W: 11272 L: 11232 D: 53894
I also incorrectly scheduled STC with [0,5] which it failed.
http://tests.stockfishchess.org/tests/view/
5af283c00ebc5968e6523f33
LLR: -2.94 (-2.94,2.94) [0.00,5.00]
Total: 12338 W: 2451 L: 2522 D: 7365
Closes https://github.com/official-stockfish/Stockfish/pull/1593
bench:
4698290
----------------------------------------
Thanks to @vondele and @Rocky640 for a cleaner version of the patch,
and the following comments!
> Most of the pinned, (or for this pull request, blocking) squares were
> already computed in the unsafeChecks, the only missing squares being:
>
> a) squares attacked by a Queen which are occupied by friendly piece
> or "unsafe". Note that adding such squares never passed SPRT[0,5].
>
> b) squares not in mobilityArea[Us].
>
> There is a strong relationship between the blockers and the unsafeChecks,
> but the bitboard unsafeChecks is still useful when the checker is not
> aligned with the king, and the checking square is occupied by friendly
> piece or is "unsafe". This is always the case for the Knight.
protonspring [Thu, 10 May 2018 13:46:13 +0000 (15:46 +0200)]
Consolidate pawn storm types
Simplification: the Unopposed and Unblocked pawn storm types are mathematically
similar enough to combine with no Elo loss. This reduces the pawn storm types
to BlockedByPawn and UnBlocked.
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 116869 W: 23549 L: 23605 D: 69715
http://tests.stockfishchess.org/tests/view/
5af2def90ebc5968e6523f82
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39912 W: 6090 L: 5998 D: 27824
http://tests.stockfishchess.org/tests/view/
5af3b2e20ebc5968e6524013
Closes https://github.com/official-stockfish/Stockfish/pull/1592
Bench:
5244314
Stefan Geschwentner [Thu, 10 May 2018 10:27:14 +0000 (12:27 +0200)]
Tune null move pruning
Use a lower stat score threshold of 22500.
Failed yellow at STC after many games (~0.92 Elo):
LLR: -2.96 (-2.94,2.94) [0.00,4.00]
Total: 73978 W: 14947 L: 14834 D: 44197
http://tests.stockfishchess.org/tests/view/
5af2deec0ebc5968e6523f80
But scales good and passed LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 23147 W: 3453 L: 3237 D: 16457
http://tests.stockfishchess.org/tests/view/
5af3cf820ebc5968e6524022
Closes https://github.com/official-stockfish/Stockfish/pull/1591
Bench:
4777674
candirufish [Wed, 9 May 2018 07:18:22 +0000 (09:18 +0200)]
Tuned some pawns and evaluation constants
Tuned values in pawns.cpp and evaluate.cpp after a SPSA session:
419k games 60sec 600nodetime. We have adjusted the PassedRank[]
output of the SPSA session to keep increasing values with rank,
and PassedFile[] output to keep the West <–> East symmetry of
the evaluation.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 58948 W: 12431 L: 12046 D: 34471
http://tests.stockfishchess.org/tests/view/
5af2302f0ebc5968e6523f0a
LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 22211 W: 3468 L: 3251 D: 15492
http://tests.stockfishchess.org/tests/view/
5af264c80ebc5968e6523f1a
See https://github.com/official-stockfish/Stockfish/pull/1587
and https://github.com/official-stockfish/Stockfish/pull/1590
bench:
4437531
Joost VandeVondele [Tue, 8 May 2018 23:40:32 +0000 (01:40 +0200)]
Remove goto, limit skipping to NMP
This patch simplifies the control flow in search(), removing an if
and a goto. A side effect of the patch is that Stockfish is now a
little bit more selective at low depths, because we allow razoring,
futility pruning and probcut pruning after a null move.
passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 32035 W: 6523 L: 6422 D: 19090
http://tests.stockfishchess.org/tests/view/
5af142ca0ebc597fb3d39bb6
passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 41431 W: 6187 L: 6097 D: 29147
http://tests.stockfishchess.org/tests/view/
5af148770ebc597fb3d39bc1
Ideas for further work:
• Use the nodes credit opened by the patch (the increased selectivity)
to try somewhat higher razoring, futility or probcut margins at [0..4].
Bench:
4855031
Stefan Geschwentner [Tue, 8 May 2018 17:03:22 +0000 (19:03 +0200)]
Tweak null move pruning conditions
Allow null move pruning only if last stat score < 30000.
Passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 12653 W: 2641 L: 2454 D: 7558
http://tests.stockfishchess.org/tests/view/
5af1d8830ebc5968e6523edb
Passed LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 19782 W: 3072 L: 2878 D: 13832
http://tests.stockfishchess.org/tests/view/
5af1ee8c0ebc5968e6523ee4
Ideas for further work:
• Tune the stat score threshold.
• Try depth based stat score threshold.
• Try stat score condition for other prunings.
Closes https://github.com/official-stockfish/Stockfish/pull/1589
Bench:
5088156
Alain SAVARD [Tue, 8 May 2018 09:00:51 +0000 (11:00 +0200)]
Drop the lever condition for backwards
We can view the patch version as adding some "undermining bonus" for
level pawns, when the defending side can not easily avoid the exchange
by advancing her pawn.
• Case 1) White b2,c3, Black a3,b3:
Black is breaking through, b2 deserves a penalty
• Case 2) White b2,c3, Black a3,c4:
if b2xa3 then White ends up with a weak pawn on a3
and probably a weak pawn on c3 too.
In either case, White can still not safely play b2-b3 and make a
phalanx with c3, which is the essence of a backward pawn definition.
Passed STC in SPRT[0, 4]:
LLR: -2.96 (-2.94,2.94) [0.00,4.00]
Total: 131169 W: 26523 L: 26199 D: 78447
http://tests.stockfishchess.org/tests/view/
5aefa4d50ebc5902a409a151
ELO 1.19 [-0.38,2.88] (95%)
Passed LTC in SPRT[-3, 1]:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 24824 W: 3732 L: 3617 D: 17475
http://tests.stockfishchess.org/tests/view/
5af04d3f0ebc5902a88b2e55
ELO 1.27 [-1.21,3.70] (95%)
Closes https://github.com/official-stockfish/Stockfish/pull/1584
How to continue from there?
There were some promising tests a couple of months ago about adding
a lever condition for king danger in evaluate.cpp, maybe it would
be time to re-try this after all the recent changes in pawns.cpp
Bench:
4773882
Joost VandeVondele [Tue, 8 May 2018 08:43:46 +0000 (10:43 +0200)]
Remove skipEarlyPruning argument to search()
Remove nine boolean arguments and the corresponding skipEarlyPruning variable.
Instead, skip early pruning only when there is an excluded move, and try null
move pruning only if the previous move was not itself a null move.
passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 33623 W: 6853 L: 6755 D: 20015
http://tests.stockfishchess.org/tests/view/
5aef462a0ebc5902a409a10e
passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39474 W: 5882 L: 5789 D: 27803
http://tests.stockfishchess.org/tests/view/
5aefd4b80ebc5902a409a164
Closes https://github.com/official-stockfish/Stockfish/pull/1585
Bench:
4953556
Joost VandeVondele [Tue, 8 May 2018 08:31:20 +0000 (10:31 +0200)]
Improve signature script
Catch case of missing bench, indicative of a crash or assert.
No functional change
protonspring [Sun, 6 May 2018 07:42:49 +0000 (09:42 +0200)]
Simplify the backward pawns code
The two lines of code in the patch seem to be just as good as master.
1. We now only look at the current square to see if it is currently backward,
whereas master looks there AND further ahead in the current file (master would
declare a pawn "backward" even though it could still safely advance a little).
This simplification allows us to avoid the use of the difficult logic with
`backmost_sq(Us, neighbours | stoppers)`.
2. The condition `relative_rank(Us,s) < RANK_5` is simplified away.
Passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 68132 W: 14025 L: 13992 D: 40115
http://tests.stockfishchess.org/tests/view/
5aedc97a0ebc5902a4099fd6
Passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 23789 W: 3643 L: 3527 D: 16619
http://tests.stockfishchess.org/tests/view/
5aee4f970ebc5902a409a03a
Ideas for further work:
• The new code flags some pawns on the 5th rank as backward, which was not the
case in the old master. So maybe we should test a version with that included?
• Further tweaks of the backward condition with [0..5] bounds?
Closes https://github.com/official-stockfish/Stockfish/pull/1583
Bench:
5122789
Stéphane Nicolet [Wed, 2 May 2018 19:49:54 +0000 (21:49 +0200)]
Tweak the connected[] array value for pawns on rank 5
A recent tuning session by Jerry Donald Watson suggested that the
value for the pawns on the fifth rank in the connected[] array were
a little bit too high in master. We lower here this value from 75 to 65.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 27399 W: 5646 L: 5384 D: 16369
http://tests.stockfishchess.org/tests/view/
5aea17c50ebc5902a1bed396
LTC:
LLR: 3.66 (-2.94,2.94) [0.00,4.00]
Total: 95590 W: 14529 L: 14062 D: 66999
http://tests.stockfishchess.org/tests/view/
5aea34a40ebc5902a104ebe5
Closes https://github.com/official-stockfish/Stockfish/pull/1580
Bench:
5186783
Stéphane Nicolet [Wed, 2 May 2018 11:20:47 +0000 (13:20 +0200)]
Correct a bug introduced by Stéphane in the previous patch.
When we are using the "Bitboard + Square" overloaded operators,
the compiler uses the interpediate SquareBB[s] to transform the
square into a Bitboard, and then calculate the result.
For instance, the following code:
```
b = pos.pieces(Us, PAWN) & s
```
generates in fact the code:
```
b = pos.pieces(Us, PAWN) & SquareBB[s]`
```
The bug introduced by Stéphane in the previous patch was the
use of `b = pos.pieces(Us, PAWN) & (s + Up)` which can result
in out-of-bounds errors for the SquareBB[] array if s in the
last rank of the board.
We coorect the bug, and also add some asserts in bitboard.h to
make the code more robust for this particular bug in the future.
Bug report by Joost VandeVondele. Thanks!
Bench:
5512000
protonspring [Tue, 1 May 2018 21:50:23 +0000 (23:50 +0200)]
Use special rule for BlockedByKing
Simplification: remove BlockedByKing from storm array and use a special rule.
The BlockedByKing section in the storm array is substantially similar to the
Unopposed section except for two extreme values V(-290), V(-274). Turns out
removing BlockedByKing and using a special rule for these two values shows
no Elo loss. All the other values in the BlockedByKing section are apparently
irrelevant. BlockedByKing now falls under unopposed which (to me) is a bit
more logical since there is no defending pawn on this file. Also, retuning
the Unopposed section may be another improvement.
GOOD) This is a simplification because the entire BlockedByKing section of
the storm array goes away reducing a few lines of code (and less values to
tune). This also brings clarity because the special rule is self documenting.
BAD) It takes execution time to apply the special rule. This should be negli-
gible because it is based on a template parameter and is boiled down to two
bitwise AND's.
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 33470 W: 6820 L: 6721 D: 19929
http://tests.stockfishchess.org/tests/view/
5ae7b6e60ebc5926dba90e13
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 47627 W: 7045 L: 6963 D: 33619
http://tests.stockfishchess.org/tests/view/
5ae859ff0ebc5926dba90e85
Closes https://github.com/official-stockfish/Stockfish/pull/1574
Bench:
5512000
-----------
How to continue after this patch?
This patch may open the possibility to move the special rule to evaluate.cpp
in the evaluate::king() function, where we could refine the rule using king
danger information. For instance, with a king in H2 blocking an opponent pawn
in H3, it may be critical to know that the opponent has no safe check in G2
before giving the bonus :-)
MJZ1977 [Tue, 1 May 2018 05:12:17 +0000 (07:12 +0200)]
Penalty for bad bishop with blocked central files
We increase the penalty for bad bishops by a factor proportional
to the number of our blocked pawns in the center files C, D, E or F.
STC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 8868 W: 1870 L: 1700 D: 5298
http://tests.stockfishchess.org/html/live_elo.html?
5ae7674f0ebc590e39268b34
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 5813 W: 950 L: 808 D: 4055
http://tests.stockfishchess.org/html/live_elo.html?
5ae77bae0ebc5926dba90dd9
Closes https://github.com/official-stockfish/Stockfish/pull/1573
Bench:
5364190
Stefano80 [Sun, 29 Apr 2018 05:23:32 +0000 (07:23 +0200)]
Always scale using pawn contribution
This is a further step in the long quest for a simple way of determining
scale factors for the endgame.
Here we remove the artificial restriction in evaluate_scale_factor()
based on endgame score. Also SCALE_FACTOR_ONEPAWN can be simplified
away. The latter is a small non functional simplification with respect
to the version that was testedin the framework, verified on bench with
depth 22 for good measure.
Passed STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 49438 W: 9999 L: 9930 D: 29509
http://tests.stockfishchess.org/tests/view/
5ae20c8b0ebc5963175205c8
Passed LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 101445 W: 15113 L: 15110 D: 71222
http://tests.stockfishchess.org/tests/view/
5ae2a0560ebc5902a1998986
How to continue from there?
Maybe the general case could be scaled with pawns from both colors
without losing Elo. If that is the case, then this could be merged
somehow with the scaling in evaluate_initiative(), which also uses
a additive malus down when the number of pawns in the position goes
down.
Closes https://github.com/official-stockfish/Stockfish/pull/1570
Bench:
5254862
Joost VandeVondele [Thu, 26 Apr 2018 14:56:52 +0000 (16:56 +0200)]
Simplifiy IID condition
do IID for all sufficiently deep searches without TT move.
passed STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 25494 W: 5313 L: 5199 D: 14982
http://tests.stockfishchess.org/tests/view/
5ae1e8dd0ebc596317520583
passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 80582 W: 12162 L: 12130 D: 56290
http://tests.stockfishchess.org/tests/view/
5ae1f5ab0ebc5963175205a4
Bench:
4966970
Joost VandeVondele [Thu, 26 Apr 2018 22:07:56 +0000 (00:07 +0200)]
Fix 'make strip' for mingw.
Currently the make strip target is broken on mingw as the exe name is wrong (stockfish instead of stockfish.exe).
Needs some testing by mingw users (both profile-build and strip, native and cross).
No functional change.
Stéphane Nicolet [Sun, 29 Apr 2018 04:48:18 +0000 (06:48 +0200)]
Update various comments
Spotted by Alain Savard, Joost VandeVondele, Ronald de Man, Fabian Fichter, Chris Cain, xoto10
No functional change
Alain SAVARD [Mon, 23 Apr 2018 19:49:34 +0000 (15:49 -0400)]
No Queen in the MobilityArea
Queen was recently excluded from the mobility area of friendly minor
pieces. Exclude queen also from the mobility area of friendly majors too.
Run as a simplification:
STC
http://tests.stockfishchess.org/tests/view/
5ade396f0ebc59602d053742
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 46972 W: 9511 L: 9437 D: 28024
LTC
http://tests.stockfishchess.org/tests/view/
5ade64b50ebc5949f20a24d3
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 66855 W: 10157 L: 10105 D: 46593
How to continue from there?
The mobilityArea is used in various places of the evaluation as a
soft proxy for "not attacked by the opponent pawns". Now that the
mobility area is getting smaller and smaller, it may be worth to
hunt for Elo gains by trying the more direct ~attackedBy[Them][PAWN]
instead of mobilityArea[Us] in these places.
Bench:
4650572
Stéphane Nicolet [Mon, 23 Apr 2018 07:48:53 +0000 (09:48 +0200)]
Simplify the ShelterStrength[] array
Remove the distinction between the king file and the two neighbours
files in the ShelterStrength[] array. Instead we initialize the safety
variable in the evaluate_shelter() function with a -10 penalty if our
king is on a semi-open file (ie. if our king is on a file without a pawn
protection).
Also rename shelter_storm() to evaluate_shelter() while there.
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 23153 W: 4795 L: 4677 D: 13681
http://tests.stockfishchess.org/tests/view/
5adcb83d0ebc595ec7ff8aa7
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 25728 W: 3934 L: 3821 D: 17973
http://tests.stockfishchess.org/tests/view/
5adcdcb60ebc595ec7ff8adb
See the commit history in PR#1559 for the proof that the committed
version is equivalent to the version in the tests above:
https://github.com/official-stockfish/Stockfish/pull/1559
Full credit to @protonspring for the renormalized values of the
ShelterStrength[] array used for the simplification. Thanks!
Bench:
4703935
ceebo [Mon, 23 Apr 2018 07:13:07 +0000 (09:13 +0200)]
Alternative formula for dynamic contempt
Replace the formula involving arctan with something having similar
behaviour that can be implemented using integer-only operations.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 34781 W: 7189 L: 7093 D: 20499
http://tests.stockfishchess.org/tests/view/
5ad7c95f0ebc595700526e76
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 39743 W: 5950 L: 5857 D: 27936
http://tests.stockfishchess.org/tests/view/
5ad886ee0ebc595700526e9b
Closes https://github.com/official-stockfish/Stockfish/pull/1558
Bench:
5549801
Joost VandeVondele [Mon, 23 Apr 2018 06:45:50 +0000 (08:45 +0200)]
Remove template W param
Different W template parameters for the different statEntries are
not needed, simplify by consistently using 32.
Passed STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 21683 W: 4545 L: 4424 D: 12714
http://tests.stockfishchess.org/tests/view/
5ad797550ebc595700526e59
Passed LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 110391 W: 16551 L: 16562 D: 77278
http://tests.stockfishchess.org/tests/view/
5ad7a88f0ebc595700526e61
Closes https://github.com/official-stockfish/Stockfish/pull/1557
Bench:
5120532
Stéphane Nicolet [Thu, 19 Apr 2018 02:16:19 +0000 (04:16 +0200)]
Allow UCI parameters to be double
Change the operators of the Option type in uci.h to accept floating
point numbers in double precision on input as the numerical type for
the "spin" values of the UCI protocol.
The output of Stockfish after the "uci" command is unaffected.
This change is compatible with all the existing GUI (as they will
continue sending integers that we can interpret as doubles in SF),
and allows us to pass double parameters to Stockfish in the console
via the "setoption" command. This will be useful if we implement
another tuner as an alternative for SPSA.
Closes https://github.com/official-stockfish/Stockfish/pull/1556
No functional change.
---------------------
A example of the new functionality in action in the branch `tune_float2'`:
https://github.com/snicolet/Stockfish/commit/
876c322d0f20ee232da977b4d3489c4cc929765e
I have added the following lines in ucioptions.cpp:
```C++
void on_pi(const Option& o)
{
double x = Options["PI"]; // or double x = o;
std::cerr << "received value is x = " << x << std::endl;
}
...
o["PI"] << Option(3.
1415926, -
10000000,
10000000, on_pi);
```
Then I can change the value of Pi in Stockfish via the command line, and
check that Stockfish understands a floating point:
````
> ./stockfish
> setoption name PI value 2.
7182818284
received value is x = 2.71828
````
On output, the default value of Pi is truncated to 3 (to remain compatible
with the UCI protocol and GUIs):
````
> uci
[...]
option name SyzygyProbeLimit type spin default 6 min 0 max 6
option name PI type spin default 3 min -
10000000 max
10000000
uciok
````
protonspring [Wed, 18 Apr 2018 18:03:37 +0000 (20:03 +0200)]
Simplify BlockedByKing in pawn storms
This patch is non-functional. Current master does four operations to determine
whether an enemy pawn on this file is blocked by the king or not
```
f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 )
```
By adding a direction (based on the template color), this is reduced to two
operations. This works because b is limited to enemy pawns that are ahead of
the king and on the current file.
```
shift<Down>(b) & ksq
```
I've added a line of code, but the number of executing instructions is reduced
(I think). I'm not sure if this counts as a simplification, but it should
theoretically be a little faster (barely). The code line length is also reduced
making it a little easier to read.
Closes https://github.com/official-stockfish/Stockfish/pull/1552
No functional change.
Stéphane Nicolet [Wed, 18 Apr 2018 17:53:39 +0000 (19:53 +0200)]
Simplify the shelter mask
The line 246 of pawns.cpp is not necessary, because we restrict the bitboards
to file_of(f) in lines 253 and 256 anyway.
No functional change.
Alain SAVARD [Wed, 18 Apr 2018 17:44:22 +0000 (19:44 +0200)]
Tidy up on Overload
Move new code in the if (defended | weak) {} section.
No functional change
Joost VandeVondele [Wed, 18 Apr 2018 17:17:16 +0000 (19:17 +0200)]
Document Elo impact of the LMR part of search
Similar to before, document Elo impact of various LMR steps
Tests run by @jerrydonaldwatson
t1 http://tests.stockfishchess.org/tests/view/
5abece950ebc591a560aad0b
t2 http://tests.stockfishchess.org/tests/view/
5abecf0c0ebc591a560aad0d
t3 http://tests.stockfishchess.org/tests/view/
5abecf7b0ebc591a560aad0f
t4 http://tests.stockfishchess.org/tests/view/
5abecfe70ebc591a560aad14
t5 http://tests.stockfishchess.org/tests/view/
5abed42b0ebc591a560aad33
t6 http://tests.stockfishchess.org/tests/view/
5abed0b90ebc591a560aad19
t7 http://tests.stockfishchess.org/tests/view/
5abed1240ebc591a560aad1b
t8 http://tests.stockfishchess.org/tests/view/
5abed1b90ebc591a560aad1d
No functional change.
syzygy1 [Wed, 18 Apr 2018 16:38:38 +0000 (18:38 +0200)]
Tablebases root ranking
This patch corrects both MultiPV behaviour and "go searchmoves" behaviour
for tablebases.
We change the logic of table base probing at root positions from filtering
to ranking. The ranking code is much more straightforward than the current
filtering code (this is a simplification), and also more versatile.
If the root is a TB position, each root move is probed and assigned a TB score
and a TB rank. The TB score is the Value to be displayed to the user for that
move (unless the search finds a mate score), while the TB rank determines which
moves should appear higher in a multi-pv search. In game play, the engine will
always pick a move with the highest rank.
Ranks run from -1000 to +1000:
901 to 1000 : TB win
900 : normally a TB win, in rare cases this could be a draw
1 to 899 : cursed TB wins
0 : draw
-1 to -899 : blessed TB losses
-900 : normally a TB loss, in rare cases this could be a draw
-901 to -1000 : TB loss
Normally all winning moves get rank 1000 (to let the search pick the best
among them). The exception is if there has been a first repetition. In that
case, moves are ranked strictly by DTZ so that the engine will play a move
that lowers DTZ (and therefore cannot repeat the position a second time).
Losing moves get rank -1000 unless they have relatively high DTZ, meaning
they have some drawing chances. Those get ranks towards -901 (when they
cross -900 the draw is certain).
Closes https://github.com/official-stockfish/Stockfish/pull/1467
No functional change (without tablebases).
syzygy1 [Wed, 18 Apr 2018 15:30:00 +0000 (17:30 +0200)]
Analysis Contempt combo box
This patch introduces an Analysis Contempt UCI combo box to control
the behaviour of contempt during analysis. The possible values are
Both, Off, White, Black. Technically, the engine is supposed to be in
analysis mode if UCI_AnalyseMode is set by the graphical user interface
or if the user has chosen infinite analysis mode ("go infinite").
Credits: the idea for the combo box is due to Michel Van den Bergh.
No functional change (outside analysis mode).
-----------------------------------------------------
The so-called "contempt" is an optimism value that the engine adds
to one color to avoid simplifications and keep tension in the position
during its search. It was introduced in Stockfish 9 and seemed to give
good results during the TCEC 11 tournament (Stockfish seemed to play a
little bit more actively than in previous seasons).
The patch does not change the play during match or blitz play, but gives
more options for correspondance players to decide for which color(s) they
would like to use contempt in analysis mode (infinite time). Here is a
description of the various options:
* Both : in analysis mode, use the contempt for both players (alternating)
* Off : in analysis mode, use the contempt for none of the players
* White : in analysis mode, White will play actively, Black will play passively
* Black : in analysis mode, Black will play actively, White will play passively
syzygy1 [Sat, 14 Apr 2018 06:36:29 +0000 (08:36 +0200)]
Fix reported DTZ for mate-in-1-ply positions
This corrects a bug in Tablebases::probe_dtz() which sometimes causes
a higher DTZ value to be returned for the position one ply before mate
than for the position two plies before mate.
The problem was reported by Kolja Kühn here:
http://talkchess.com/forum/viewtopic.php?p=757497#757497
It is explained here:
http://talkchess.com/forum/viewtopic.php?p=757506#757506
I have also adjusted some comments to make clear that probe_dtz()
returns -1 for a mate position.
Closes https://github.com/official-stockfish/Stockfish/pull/1546
No functional change
Marco Costalba [Thu, 12 Apr 2018 07:22:40 +0000 (09:22 +0200)]
Further documentation and coding style on TB code
This patch adds some documentation and code cleanup to tablebase code.
It took me some time to understand the relation among the differrent
structs, although I have rewrote them fully in the past. So I wrote
some detailed documentation to avoid the same efforts for future readers.
Also noteworthy is the use a standard hash table implementation with a
more efficient 1D array instead of a 2D array. This reduces the average
lookup steps of 90% (from 343 to 38 in a bench 128 1 16 run) and reduces
also the table from 5K to 4K
entries.
I have tested on 5-men and no functional and no slowdown reported. It
should be verified on 6-men that the new hash does not overflow. It is
enough to run ./stockfish with 6-men available: if it does not assert at
startup it means everything is ok with 6-men too.
EDIT: verified for 6-men tablebase by Jörg Oster. Thanks!
No functional change.
Jerry Donald Watson [Mon, 9 Apr 2018 23:28:26 +0000 (00:28 +0100)]
Simplify condition in space definition
We remove an unnecessary condition in the definition of safe squares
in the space evaluation. Only the squares which are occupied by our
pawns or attacked by our opponent's pawns are now excluded.
STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 21096 W: 4321 L: 4199 D: 12576
http://tests.stockfishchess.org/tests/view/
5acbf7510ebc59547e537d4e
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 23437 W: 3577 L: 3460 D: 16400
http://tests.stockfishchess.org/tests/view/
5acc0f750ebc59547e537d6a
It may be possible to further refine the definition of such safe squares.
Bench:
5351765
VoyagerOne [Sat, 7 Apr 2018 13:46:29 +0000 (09:46 -0400)]
Reset negative statScore on fail high
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 9073 W: 1937 L: 1766 D: 5370
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 53530 W: 8139 L: 7823 D: 37568
Bench:
5170165
Mark Tenzer [Fri, 6 Apr 2018 23:20:48 +0000 (01:20 +0200)]
Introduce Overload
This patch applies a S(10, 5) bonus for every square that is:
- Occupied by an enemy piece which is not a pawn
- Attacked exactly once by our pieces
- Defended exactly once by enemy pieces
The idea is that these pieces must be defended. Their defenders have
dramatically limited mobility, and they are vulnerable to our future
attack.
As with connectivity, there are probably many more tests to be run in
this area. In particular:
- I believe @snicolet's queen overload tests have demonstrated a potential
need for a queen overload bonus above and beyond this one; however, the
conditions for "overload" in this patch are different (excluding pieces
we attack twice). My next test after this is (hopefully) merged will be
to intersect the Bitboard I define here with the enemy's queen attacks and
attempt to give additional bonus.
- Perhaps we should exclude pieces attacked by pawns--can pawns really be
overloaded? Should they have the same weight, or less? This didn't work
with a previous version, but it could work with this one.
- More generally, different pieces may need more or less bonus. We could
change bonuses based on what type of enemy piece is being overloaded, what
type of friendly piece is attacking, and/or what type of piece is being
defended by the overloaded piece and attacked by us, or any intersection
of these three. For example, here attacked/defended pawns are excluded,
but they're not totally worthless targets, and could be added again with
a smaller bonus.
- This list is by no means exhaustive.
STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 17439 W: 3599 L: 3390 D: 10450
http://tests.stockfishchess.org/tests/view/
5ac78a2e0ebc59435923735e
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 43304 W: 6533 L: 6256 D: 30515
http://tests.stockfishchess.org/tests/view/
5ac7a1d80ebc59435923736f
Closes https://github.com/official-stockfish/Stockfish/pull/1533
Bench:
5248871
----------------
This is my first time opening a PR, so I apologize if there are errors.
There are too many people to thank since I submitted my first test just
over a month ago. Thank you all for the warm welcome and here is to more
green patches!
In particular, I would like to thank:
- @crossbr, whose comment in a FishCooking thread first inspired me to
consider the overloading of pieces other than queens,
- @snicolet, whose queen overload tests inspired this one and served as
the base of my first overload attempts,
- @protonspring, whose connectivity tests inspired this one and who provided
much of the feedback needed to take this from red to green,
- @vondele, who kindly corrected me when I submitted a bad LTC test,
- @Rocky640, who has helped me over and over again in the past month.
Thank you all!