Heimdall 1.4.2 - new version chess engine

Heimdall - UCI chess engine written in Nim.

Author: Mattia Giambirtone

More info
Heimdall is available on Lichess under its old name (Nimfish), feel free to challenge it! I try to keep the engine running on there always up to date with the changes on the master branch

Heimdall 1.4.2 what's new?

Nothing to see here, move along

Greetings! This release exists mostly to address a nasty bug caused by incorrect score clamping that would make heimdall find non-existent M127 lines in positions with a very high evaluation

What changed

The aforementioned bug has been fixed

All of heimdall's parameters were tuned to account for the addition of correction history

The TT score is used in place of the static eval in RFP when possible

Game Strength Change/Tests

Nothing particularly interesting here, I'm just adding this section for completeness

UHO_Lichess_4852_v1.epd

STC:

Elo   | 4.34 +- 7.76 (95%)

Conf  | 40.0+0.40s Threads=1 Hash=64MB

Games | N: 2002 W: 453 L: 428 D: 1121

Penta | [4, 229, 512, 250, 6]

https://kelseyde.pythonanywhere.com/test/1688/

LTC:

Elo   | 1.56 +- 5.48 (95%)

Conf  | 40.0+0.40s Threads=1 Hash=64MB

Games | N: 2002 W: 160 L: 151 D: 1691

Penta | [0, 123, 748, 128, 2]

Heimdall 1.3.0 vs other engines:

Horsie 1.0.6 JA	1.5/12	-9	12 Games
Viridithas 16.0.0	1/8	-6	8 Games
Sting Black Hole 9	6/6	+6	6 Games
Deep HIARCS 15.4u	4/6	+2	6 Games
Ethereal 14.25	2/6	-2	6 Games
Chess-System-Tal-2	2/6	-2	6 Games
Caissa 1.21	2/6	-2	6 Games
Alexandria 7.0.14 JA	2/6	-2	6 Games
Revenge 4.0	2/6	-2	6 Games
Motor 0.8.0 JA	2/6	-2	6 Games
Lizard 11.2.0	1.5/6	-3	6 Games
PlentyChess 4.0.1	1.5/6	-3	6 Games
Clover 8.1 JA	1.5/6	-3	6 Games
HypnoS ++ 1.01	1.5/6	-3	6 Games
Artemis 7TR	1.5/6	-3	6 Games
Dragon 3.3	1.5/6	-3	6 Games
Velvet 8.1.1 JA	1/6	-4	6 Games
Obsidian 15.01 SE	1/6	-4	6 Games
Starzix 6.0	1/6	-4	6 Games
Igel 3.6.0 JA	1/6	-4	6 Games
Stockfish dev-20250202	0.5/6	-5	6 Games

Heimdall 1.4.2 download  mirror

Github: https://github.com/nocturn9x/heimdall