Gwaihir - UCI Compatible chess engine

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Gwaihir is a strong (hopefully in the future) UCI compatible chess engine written in C++.

Features list

Board representation:

• Move generation (with Magic Bitboards)
• Constrution of position from FEN

Search:

• Negamax
• Alpha-Beta pruning
• Move Ordering (Hash > MVV-LVA > Killer > History)
• Iterative Deepening
• Transposition tables (with Zobrist Hashing)
• Quiescence search
• Principled Variation search
• Aspiration windows
• SEE
• Search Extensions Reductions
• Late Move Reduction (LMR)
• Null Move Pruning
• Lazy SMP

Evaluation:

• Material
• Game-Phase dependent evaluation
• Piece-Square Tables
• Pawn Structure
• Evaluation of Pieces
• Evaluation Patterns
• Mobility
• Center Control
• Connectivity
• Trapped Pieces
• King Safety
• Space
• Tempo
• Evaluation/Pawn TT

Other game phases:

• Opening book
• Endgame tablebases

Miscellaneous:

• UCI protocol implementation
• Time control

Tests:

• Perft Test

Current To-Do list

• Engine could not mate in NBK vs K endgame (sigh...)
• Figure out why are so few nodes searched if compiled with RelWithDebInfo
• 50 move rule
• MNPS drops significantly towards the endgame. Potential causes:
  • More TT hits, so nodes are not being counted.
  • History stack is getting too big.
• Minor - don't make illegal move when getting mated
• Minor - stop iterative deepening when there is a mate already

Improvements

• Extensions and Reductions
• NMP

Dependencies

Building