Chess engine: Renegade 0.11.0

Author:Krisztian Peocz  

Rating CEDR=2672

Renegade is a chess engine written in C++ using Visual Studio 2019. It values readability and simplicity, and uses the UCI protocol to communicate, making it easy to connect it to chess frontends. Under construction since October 7, 2022 and released publicly on January 15, 2023.  

The project can be compiled using Visual Studio 2019 with C++20 features enabled. The engine makes heavy use of `popcnt` and `lzcnt` instructions, thus only processors from 2013 or so are supported, but the calls to these instructions are wrapped in a custom function, and replacing them with something more compatible is relatively straightforward. Currently only Windows binaries are compiled, but in the future I would like to make them for Linux as well.

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v.0.11.0:

Improved search

Added aspiration windows

Added static exchange evaluation (and related pruning techniques)

More aggressive late-move reductions

Added mate distance pruning

Check extensions are done at any depth, instead of only at depth 0

Removed non-gaining pruning (razoring + delta pruning)

Small update to null-move pruning formula

Improved speed (roughly 30% nps uplift before other features got added)

Optimized hash calculations (no longer using 13% of the processing time!)

No longer relying on fully calculated internal attack maps

Reduced branching in move generation

Improved evaluation

Rewritten weight structure, using the S(x, y) notation

More nuanced threat calculation

Bonus for pawns supported by other pawns

Pawn phalanx evaluation

Squares attacked by pawns no longer count towards piece mobility

Further tuned existing weights

Move ordering improvements

Captures with a negative SEE moved after quiet moves

Made transposition table entries more compact (16 bytes instead of 24)

Updated tuner

Accommodates the new weight structure

Quality of life improvements

Internal changes

Templated move generation

Added method for determining whether a square is attacked

Generally trying to use more of the modern C++ features

Added functions needed for SEE

Lots of clean ups

Updated time management for repeating time controls

Now it should use more time in the beginning of the game

Hopefully I can stop complaining about this in tournaments

Pretty output (unless uci command is received)

Node counts are incremented on make move (similarly to most engines)

Fixed missing staticEval >= beta condition for null-move pruning

Fixed search aborting if mate found when not using time constraints

Made everything a little less bad

Regression testing: (time control: 10s+0.1)

Score of Renegade 0.11.0 vs Renegade 0.10.0: 2010 - 240 - 550  [0.816] 2800

...      Renegade 0.11.0 playing White: 1144 - 60 - 196  [0.887] 1400

...      Renegade 0.11.0 playing Black: 866 - 180 - 354  [0.745] 1400

...      White vs Black: 1324 - 926 - 550  [0.571] 2800

Elo difference: 258.8 +/- 13.6, LOS: 100.0 %, DrawRatio: 19.6 %

Rating CEDR=2672 Author - Krisztian Peocz

Individual statistics: Renegade 0.10.0 - 124 games (+ 20,= 17,- 87), 23.0 %

Critter 1.6a                  :   4 (+  0,=  0,-  4),  0.0 %

Jinx 1.0                      :   1 (+  1,=  0,-  0), 100.0 %

Admete 1.5.0                  :   1 (+  1,=  0,-  0), 100.0 %

K2 0.99                       :   1 (+  0,=  1,-  0), 50.0 %

Novice 3.1                    :   1 (+  0,=  0,-  1),  0.0 %

Paulchen 332 0.1.1            :   1 (+  0,=  0,-  1),  0.0 %

Amoeba 3.4                    :   1 (+  0,=  0,-  1),  0.0 %

CT800 1.44                    :   1 (+  1,=  0,-  0), 100.0 %

Inanis 1.2.0                  :   1 (+  1,=  0,-  0), 100.0 %

Rapcschess 2022-12-08         :   1 (+  0,=  1,-  0), 50.0 %

Rebel 16.2                    :   2 (+  0,=  0,-  2),  0.0 %

Leorik 2.4                    :   2 (+  0,=  0,-  2),  0.0 %

Arasan 23.5                   :   6 (+  0,=  0,-  6),  0.0 %

Knightx 3.7b                  :   6 (+  0,=  3,-  3), 25.0 %

Mayhem 8.1                    :   6 (+  2,=  1,-  3), 41.7 %

Polaris 1.4.1                 :   6 (+  1,=  2,-  3), 33.3 %

Tenax 0.7.7                   :   6 (+  0,=  0,-  6),  0.0 %

Altair 2.0.0                  :   6 (+  0,=  2,-  4), 16.7 %

BrainLearn 23.1               :   4 (+  0,=  0,-  4),  0.0 %

Jangine 2023-03-31            :   6 (+  6,=  0,-  0), 100.0 %

Midnight 5.0                  :   6 (+  0,=  1,-  5),  8.3 %

MrBob 1.2.0                   :   6 (+  0,=  0,-  6),  0.0 %

Polyfish 20230410             :   4 (+  0,=  0,-  4),  0.0 %

RubiChess 20230410            :   6 (+  0,=  0,-  6),  0.0 %

AI 28.0                       :   4 (+  0,=  0,-  4),  0.0 %

ShashChess 31.1               :   4 (+  0,=  0,-  4),  0.0 %

Zangdar 2.14.06               :   6 (+  1,=  2,-  3), 33.3 %

Svart 3.1                     :   6 (+  1,=  0,-  5), 16.7 %

Willow 2.7                    :   6 (+  1,=  1,-  4), 25.0 %

Akimbo 0.2.0                  :   6 (+  4,=  2,-  0), 83.3 %

Clover 4.0                    :   4 (+  0,=  0,-  4),  0.0 %

Corchess 20230410             :   2 (+  0,=  0,-  2),  0.0 %

Queen 4.05                    :   1 (+  0,=  1,-  0), 50.0 %

Renegade 0.11.0 download

github:https://github.com/pkrisz99/Renegade/releases/tag/v0.11.0