During recent work on threat inputs, there was a hard-to-debug crash in tbprobe
caused by incorrectly computing st->materialKey. This PR adds correctness
checking to pos_is_ok and a faster check in tbprobe that will actually run in
CI (because pos_is_ok checking is disabled even in debug mode, for performance
purposes).
closes https://github.com/official-stockfish/Stockfish/pull/6410
No functional change
The contents of DirtyThreats gets memcpyed twice for each call to do_move.
(Return value optimization doesn't apply to the do_move function itself because
it constructs a std::pair, so it gets copied; and the calls to reset also
require a copy.) This patch inserts the dirty info in place.
Sometimes the caller of do_move ignores the DirtyThreats info, so we pass in
scratch objects. I found that stack-allocating these scratch objects was bad on
Fishtest, so I begrudgingly put them in the Position struct. Both templating
the do_move function on whether dirty threats are needed and putting a
null-check branch for each use of dirty threats were slowdowns locally. Of
course, nothing prevents a future attempt at cleaning this up.
passed STC
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 68448 W: 17770 L: 17418 D: 33260
Ptnml(0-2): 198, 7425, 18630, 7769, 202
https://tests.stockfishchess.org/tests/view/6914c01a7ca87818523318ba
closes https://github.com/official-stockfish/Stockfish/pull/6414
No functional change
Only a modest amount of work happens between the transposition table prefetch
and the probe, so the probe still often stalls waiting for DRAM. The vast
majority of the time (in particular, if !checkEP), the key is known much
earlier in the do_move function and the latency can be better hidden.
passed STC SMP
https://tests.stockfishchess.org/tests/view/68f337c528e6d77fcffa066a
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 65256 W: 16806 L: 16462 D: 31988
Ptnml(0-2): 76, 7386, 17362, 7726, 78
but failed to gain STC
https://tests.stockfishchess.org/tests/view/68f3378328e6d77fcffa0665
LLR: -2.94 (-2.94,2.94) <0.00,2.00>
Total: 109824 W: 28523 L: 28618 D: 52683
Ptnml(0-2): 311, 11799, 30788, 11702, 312
In local tests, the speedup grows with thread count
closes https://github.com/official-stockfish/Stockfish/pull/6372
No functional change
for positions such as:
position fen rr6/2q2p1k/2P1b1pp/bB2P1n1/R2B2PN/p4P1P/P1Q4K/1R6 b - - 2 38 moves f7f5
position fen 8/p2r1pK1/6p1/1kp1P1P1/2p5/2P5/8/4R3 b - - 0 43 moves f7f5
position fen 4k3/4p3/2b3b1/3P1P2/4K3/8/8/8 b - - moves e7e5
ep is not possible for various reasons. Do not set the ep square and the do not change the zobrist key, as if ep were possible.
This fixes 3-fold detection, which could in rare cases be observed as a warning generated by fastchess for PVs that continued beyond an actual 3-fold.
Also fixes wrong evals for certain moves e.g. a2a1 for
position fen 4k3/1b2p2b/8/3P1P2/4K3/8/8/r7 b - - 0 1 moves e7e5 e4e3 a1a2 e3e4 a2a1 e4f3 a1a2 f3e4
fixes https://github.com/official-stockfish/Stockfish/issues/6138
originally written and tested by rn5f107s2, with small buglet as
https://tests.stockfishchess.org/tests/view/685af90843ce022d15794400
failed STC
LLR: -2.93 (-2.94,2.94) <-1.75,0.25>
Total: 130688 W: 33986 L: 34362 D: 62340
Ptnml(0-2): 414, 13292, 38302, 12928, 408
https://tests.stockfishchess.org/tests/view/688bcb35502b34dd5e7111c9
passed LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 99018 W: 25402 L: 25273 D: 48343
Ptnml(0-2): 54, 9097, 31089, 9204, 65
https://tests.stockfishchess.org/tests/view/688c613c502b34dd5e7112d3https://github.com/official-stockfish/Stockfish/pull/6211
Bench: 2946135
Co-authored-by: Joost VandeVondele <Joost.VandeVondele@gmail.com>
This condition can never be true, it's superfluous.
It never triggers even with a bench 16 1 20 run.
To met the condition it would imply that the previous recapture was done
by a higher rated piece than a Queen.
This is only the case when the King recaptures and that's already
handled in line 1161: (return (attackers & ~pieces(stm)) ? res ^ 1).
closes https://github.com/official-stockfish/Stockfish/pull/5839
No functional change
https://tests.stockfishchess.org/tests/view/6782decb6ddf09c0b4b6e1b0
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 105920 W: 27571 L: 27181 D: 51168
Ptnml(0-2): 284, 10808, 30403, 11164, 301
- If we only need to know if attackers exist we can skip some
calculations.
- Also calculating slider/magic attackers first is better because the
double lookup is slow due to memory latency.
- I also included a couple of very minor cleanups in search that
probably don't warrant their own PR but I can open separately if
that's better.
closes https://github.com/official-stockfish/Stockfish/pull/5762
No functional change
This is another refactor which aims to decouple uci from stockfish. A new engine
class manages all engine related logic and uci is a "small" wrapper around it.
In the future we should also try to remove the need for the Position object in
the uci and replace the options with an actual options struct instead of using a
map. Also convert the std::string's in the Info structs a string_view.
closes#5147
No functional change
This aims to remove some of the annoying global structure which Stockfish has.
Overall there is no major elo regression to be expected.
Non regression SMP STC (paused, early version):
https://tests.stockfishchess.org/tests/view/65983d7979aa8af82b9608f1
LLR: 0.23 (-2.94,2.94) <-1.75,0.25>
Total: 76232 W: 19035 L: 19096 D: 38101
Ptnml(0-2): 92, 8735, 20515, 8690, 84
Non regression STC (early version):
https://tests.stockfishchess.org/tests/view/6595b3a479aa8af82b95da7f
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 185344 W: 47027 L: 46972 D: 91345
Ptnml(0-2): 571, 21285, 48943, 21264, 609
Non regression SMP STC:
https://tests.stockfishchess.org/tests/view/65a0715c79aa8af82b96b7e4
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 142936 W: 35761 L: 35662 D: 71513
Ptnml(0-2): 209, 16400, 38135, 16531, 193
These global structures/variables add hidden dependencies and allow data
to be mutable from where it shouldn't it be (i.e. options). They also
prevent Stockfish from internal selfplay, which would be a nice thing to
be able to do, i.e. instantiate two Stockfish instances and let them
play against each other. It will also allow us to make Stockfish a
library, which can be easier used on other platforms.
For consistency with the old search code, `thisThread` has been kept,
even though it is not strictly necessary anymore. This the first major
refactor of this kind (in recent time), and future changes are required,
to achieve the previously described goals. This includes cleaning up the
dependencies, transforming the network to be self contained and coming
up with a plan to deal with proper tablebase memory management (see
comments for more information on this).
The removal of these global structures has been discussed in parts with
Vondele and Sopel.
closes https://github.com/official-stockfish/Stockfish/pull/4968
No functional change
The primary rationale behind this lies in the fact that enums were not
originally designed to be employed in the manner we currently utilize them.
The Value enum was used like a type alias throughout the code and was often
misused. Furthermore, changing the underlying size of the enum to int16_t broke
everything, mostly because of the operator overloads for the Value enum, were
causing data to be truncated. Since Value is now a type alias, the operator
overloads are no longer required.
Passed Non-Regression STC:
https://tests.stockfishchess.org/tests/view/6593b8bb79aa8af82b95b401
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 235296 W: 59919 L: 59917 D: 115460
Ptnml(0-2): 743, 27085, 62054, 26959, 807
closes https://github.com/official-stockfish/Stockfish/pull/4960
No functional change
Original idea by Seer chess engine https://github.com/connormcmonigle/seer-nnue,
coding done by @Disservin, code refactoring done by @locutus2 to match the style
of other histories.
This patch introduces pawn structure based history, which assings moves values
based on last digits of pawn structure hash and piece type of moved piece and
landing square of the move. Idea is that good places for pieces are quite often
determined by pawn structure of position. Used in 3 different places
- sorting of quiet moves, sorting of quiet check evasions and in history based
pruning in search.
Passed STC:
https://tests.stockfishchess.org/tests/view/65391d08cc309ae83955dbaf
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 155488 W: 39408 L: 38913 D: 77167
Ptnml(0-2): 500, 18427, 39408, 18896, 513
Passed LTC:
https://tests.stockfishchess.org/tests/view/653a36a2cc309ae83955f181
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 70110 W: 17548 L: 17155 D: 35407
Ptnml(0-2): 33, 7859, 18889, 8230, 44
closes https://github.com/official-stockfish/Stockfish/pull/4849
Bench: 1257882
Co-Authored-By: Disservin <disservin.social@gmail.com>
Co-Authored-By: Stefan Geschwentner <locutus2@users.noreply.github.com>
- remove the blank line between the declaration of the function and it's
comment, leads to better IDE support when hovering over a function to see it's
description
- remove the unnecessary duplication of the function name in the functions
description
- slightly refactored code for lsb, msb in bitboard.h There are still a few
things we can be improved later on, move the description of a function where
it was declared (instead of implemented) and add descriptions to functions
which are behind macros ifdefs
closes https://github.com/official-stockfish/Stockfish/pull/4840
No functional change
This introduces clang-format to enforce a consistent code style for Stockfish.
Having a documented and consistent style across the code will make contributing easier
for new developers, and will make larger changes to the codebase easier to make.
To facilitate formatting, this PR includes a Makefile target (`make format`) to format the code,
this requires clang-format (version 17 currently) to be installed locally.
Installing clang-format is straightforward on most OS and distros
(e.g. with https://apt.llvm.org/, brew install clang-format, etc), as this is part of quite commonly
used suite of tools and compilers (llvm / clang).
Additionally, a CI action is present that will verify if the code requires formatting,
and comment on the PR as needed. Initially, correct formatting is not required, it will be
done by maintainers as part of the merge or in later commits, but obviously this is encouraged.
fixes https://github.com/official-stockfish/Stockfish/issues/3608
closes https://github.com/official-stockfish/Stockfish/pull/4790
Co-Authored-By: Joost VandeVondele <Joost.VandeVondele@gmail.com>
