This release adds a transposition table to the engine. The rating increase as compared to Alpha 1 is about 165 Elo when running in the same gauntlet tournament. In self-play the difference is around 200 Elo.

• New Features:
  • Transposition table for search and perft.
  • Ordering on transposition table move.
  • Set TT size through --hash option or UCI parameter.
• Improvement:
  • Move check extension higher up in the search routine, to prevent quiescence search while in check.
• Changes:
  • seldepth: report max ply reached during the search, instead of selective depth at last completed iteration.
  • Count all nodes visited, instead of only nodes which generated moves.
  • Change random number generator from SmallRng to ChaChaRng for reproducible behavior between platforms/OS's/architectures/versions.
• Cleanup
  • Change Root PV handling to remove redundant code.
  • Miscellaneous small renames, refactors, and cleanups.
  • Add rand_chacha and remove SmallRng number generators.
  • Update Rand library to 0.8.3.