Redqueen Chess Engine / News: Recent posts

RedQueen 1.1.1 bug fix release

- Fixed bug at Aspiration Windows

RedQueen 1.1.0 release

- Fixed bug at discovered check pieces code;
- Improved lazy eval code;
- Code clean up;
- All evaluation parameters were externalized to a configuration file;
- Time management minor tweaks;
- Aspiration window code minor improvements;
- More agressive LMR;
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RedQueen 1.0 beta

- Code clean up;
- Minor tweaks;
- Improved king safety (added contact checks + shelter);
- Improved passed pawn code;
- Added pawn bad mobility knowledge;
- Added some elementary end game knowledge;
- Added some rules to fix material;
- Added the rule: "When ahead exchange pieces, when behind exchange pawns";
- Fixed minor bug in the pawn hash table;
- Fixed bug in the function which verifies if a move
retrieved from the hash is legal ;
- Created new UCI parameters to adjust the play style;
- Added some UCI options from the specs (search nodes and search moves);
- Fixed bug the time management routine;
- Improved aspiration window code in the search routine;
- Added futility pruning in the quiescence search;
- Other minor improvement in the search;

RedQueen release 0.9.8

- SMP support (multi-thread)
- Fixed getFEN method
- Improved evaluation - Fixing some material imbalances
- Fixed a bug at the see function
- Some refactoring at the Search class

This is a bugfix release;

- Fixed a potential memory leak at evaluatior class;
- Fixed a bug at passed pawn evaluation;
- Used a smaller value for the pawn hash size;

RedQueen/Release 0.9

- Clean up code;
- Fixed bugs;
- Implemented Non-capturing checks at quiescence search;
- Improved evaluation of passed pawns, rooks and knights:
- Added candidate passer knowledge;
- Bonus to rooks in open/half open files;
- Added knight outposts;
- PST's values refined;
- Improved LMR code/parameters;
- The PV is now retrieved from the transposition table (I was using before Bruce Moreland's method);
- Implemented singular extensions (+20 Elo worth perhaps);
- Storing static evaluation information in hash table;
- Improved move ordering;... read more

- Implemented pawn hash table (finally);
- Many code optimizations (piece square calculation, legality of moves, etc);
- Evaluator class was refactored;
- Evaluation improved: Added more chess knowledge (space, "good" mobility);
- Fixed bug at pondering code: it was not handling correctly the "ponderhit" command;
- Improved thread management in the search agent class;
- Added safe margins to the poll routine to avoid the engine forfeit on time in some time controls (Problem reported by Werner Schuele. Thanks!);
- Code clean up;

1) Improved king safety & passed pawn evaluation;
2) Fixed backward pawn evaluation;
3) Improvement on game phase calculation;
4) Piece Square table values are now incrementally updated;
5) Minor improvement in time allocation function;
6) Refactored move selection code;

Redqueen v0.7 release

1) Fixed bug at time management code. It was preventing Redqueen to play correctly using incremental TC. Reported by Ingo Bauer. Thanks!
2) Transposition table code was refactored;
3) Aspiration window code was improved;
4) Implemented Pawn on 7th rank extension;
5) Clean up on search code;
6) Search code was changed to use "fail-soft" framework;
7) Minor improvement on pawn & king move generator;
8) Changed piece material values;
9) Fixed bug at zobrist hashing code;
10) Fixed bug at function which verify legality of moves retrieved from hash;

what was done:

- Search class was completely refactored;
- fixed a lot of bugs in search;
- Optimization of evaluation method with pre-processed info;
- Improved king safety evaluation;
- Improved transposition table by implementing replacement strategies;
- Improved move ordering of root moves;
- Implemented pondering.

new features:

-improved time management: easy move, predict time used in each iteration of id loop to avoid wasting time in the last iteration if it would not be able to complete, etc;
- improved search: fixed bugs, implemented razoring, static null move, futility pruning, delta pruning, etc;
- created perft;
- Improved move ordering to use tt move, killers and history;
- created see to help on move ordering;
- fixed bugs in the evaluation function;... read more

* Time management routine fixed to support playing at fast time controls ( < 60 secs + 0) - Tested in Arena & xboard (Before that fix, Redqueen was only able to play at time controls with fixed moves per time);
* Fixed LMR code;

PS: If you are testing Redqueen I'd be glad to hear from you about suggestions, bug reports & test results. Also, if you wanna see some feature which currently is not present in Redqueen, just drop me an email (bhlangonijr@gmail.com) or contact me through sf Forums.... read more