Tuesday, August 26, 2014

Nirvanachess 1.8 Release

What is new in this release?

  • Strength Increase
    • Scores 55% against Nirvanachess 1.7!
  • Evaluation Tweaks
    • Blocked passed pawns with a friendly blocker are now not penalized as much
    • The Bishop pair is now based more than just the number of remaining pawns
      • Includes enemy major and minor pieces
    • Reverted Rook and Queen outposts
      • Testing proved this to be a regression against other opponents
    • Implemented a lazy evaluation based on material.
    • Implemented Pawn hashing as well as pawn shelter hashing.
  •  Search Tweaks
    • Reverted LMP for bad captures
      • Testing showed poor results at long time controls.
  • Transposition Table Tweaks
    •  Pv is no longer collected from the transposition table.
    • Hashing now uses a cluster of four entries like in Fruit and Stockfish
    • Hashing no longer uses an always replace scheme
      • Older entries, Lower depth entries and non-pv entries are given lower prority
        • Performs much better under high hash pressure
  •  Bug Fixes
    • Fixed a bug where under certain conditions killer moves would not be updated properly
    • Standardized pruning at root and interior nodes
    • Fixed a bug that caused all moves to be generated under certain conditions in Qsearch

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