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Meltdown 1.9 - new chess engine


Meltdown - UCI chess engine
Author: Hans Binderup

NOTE: this is a hobby project that is work in progress.
C++26 chess engine.

Meltdown 1.9 - what's new in this version?

Test results (v1.9 vs v1.8)
Elo | 109.22 +- 11.14 (95%)
Conf | 8.0+0.08s Threads=1 Hash=128MB
Games | N: 2004 W: 933 L: 323 D: 748
Penta | [3, 118, 333, 362, 186]
https://openbench.bunny.beer/test/526/

Elo | 126.69 +- 16.32 (95%)
Conf | 40.0+0.40s Threads=1 Hash=256MB
Games | N: 1002 W: 486 L: 136 D: 380
Penta | [4, 45, 153, 195, 104]
https://openbench.bunny.beer/test/527/

Elo | 126.69 +- 15.92 (95%)
Conf | 5.0+0.05s Threads=4 Hash=64MB
Games | N: 1002 W: 480 L: 130 D: 392
Penta | [5, 38, 158, 202, 98]
https://openbench.bunny.beer/test/529/

Elo | 121.85 +- 13.88 (95%)
Conf | 20.0+0.20s Threads=4 Hash=256MB
Games | N: 1000 W: 444 L: 107 D: 449
Penta | [3, 23, 179, 224, 71]
https://openbench.bunny.beer/test/531/

Elo | 108.68 +- 16.39 (95%)
Conf | 8.0+0.08s Threads=1 Hash=128MB (5man syzygy)
Games | N: 1000 W: 461 L: 158 D: 381
Penta | [5, 60, 158, 181, 96]
https://openbench.bunny.beer/test/532/

What's Changed
meson: add compilation options for older systems by @hansbinderup in #156
build: add '--native' option to script by @hansbinderup in #157
transposition: add tt pv | remove pv move picking by @hansbinderup in #153
searcher: isPv and isRoot as constexpr parameters by @hansbinderup in #154
repetitions: improve repetition detection | correct uci input bug by @hansbinderup in #159
move_picker: add scoring phase by @clarashepherd in #158
move_picker: lazy move picking by @clarashepherd in #160
Revert "move_picker: lazily pick TT move" by @clarashepherd in #163
evaluation: add king pawn cache by @hansbinderup in #162
spsa: apply tuning from spsa-1.8 by @hansbinderup in #164
bench: increase default depth 8=>10 by @hansbinderup in #165
evaluation: add draw contempt factor by @hansbinderup in #166
terms: add pawn storm by @hansbinderup in #167
build: align names | force clang-format | add -b to bench by @hansbinderup in #168
terms: add pawn phalanx by @hansbinderup in #169
build: default to llvm toolchain by @hansbinderup in #170
Clara/combine picker phases by @clarashepherd in #161
searcher: minor prevMove optimizations by @hansbinderup in #173
searcher: add isChecked to negamax eval by @hansbinderup in #174
search: add correction history by @hansbinderup in #176
correction_history: add threat history by @hansbinderup in #177
terms: add bishop long diagonal by @hansbinderup in #178
move_picker: pre-score quiet phases by @clarashepherd in #175



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