v2.0.0

Magic bitboard move generation, much better evaluation, check extensions and more.

New Features

• Magic bitboard movegen (#32)
• Tapered evaluation
• Passed pawn evaluation
• Enhanced mobility evaluation (weighting by piece type / game phase)
• Pawn structure hash table
• Check extensions
• Add support for the UCI go movetime command

Improvements

• A bunch of C++ related optimizations (#33)
• Tons of code cleanups (#34)
• Bulk counting of leaf nodes when performing perft (#33)
• More informative printboard output
• Remove broken backward pawn evaluation
• Remove all uses of C++ exceptions and compile with -fno-exceptions
• Improve showbb.py debugging script

Bugfixes

• Fix crash with negative perft value (#34)

MinGW Windows binaries are attached for 32 and 64 bit systems
SHA256 Sums:

8bc78d635f996516d46cc306eb475524486cfe5569d86f6c1b6bfef00484fe21  shallowblue_x86-64.exe
39817adecc38dc2645154e72a8ebf6cd7cd25ff91ea7073d67981062433dda08  shallowblue_x86.exe

v1.1.0

Bugfixes, major improvements and new features

New features:

• Add support for threefold repetition and 50 move rule draws (#28)
• Add support for PolyGlot opening books (#27)
• Overhaul evaluation (#25)
  • Add pawn structure evaluation
  • Add king safety evaluation
  • Add evaluation of rooks on open files
  • Add bishop pair evaluation
  • Clean up and optimize mobility evaluation
• Switch search algorithm to principal variation search (#25)
• Support more of the UCI protocol (#23)
  • Add support for UCI timers
  • Add support for go infinite
  • Add support for stop
• Greatly improve move ordering (#22)
  • Implement killer heuristic
  • Implement history heuristic

Improvements:

• Consider promotions in quiescence search (#30)
• Completely refactor and clean up attack generation code (#29)
• Make project buildable with LLVM and build with gcc and LLVM on Travis (#24)
• Obtain the principal variation from the transposition table, rather than using messy stack code (#22)

Bugfixes:

• Fix transposition table not overwriting old entries (#22)
• Fix incorrect MVV/LVA ordering (#22)
• Fix Zobrist keys incorrectly hashing castling rights

MinGW Windows binaries are attached for 32 and 64 bit systems
SHA256 sums:

20b6d355abe339422b7bd19c0982107c6e5567e00a648ddf13eb18f29cba12fb  shallowblue_x86-64.exe
11460e46b7554e087ab324ee69ea4b48a7608a17e59690b921f584fa54800a47  shallowblue_x86.exe

v1.0.4

Major performance improvements, bug fixes and code cleanups.

• Greatly improve move ordering, speeding up search several fold in most cases
• Clean up code related to move ordering and evaluation
• Fix crash upon searching from a mated position
• Fix incorrect UCI nodes output
• Improve debugging scripts

MinGW Windows binaries are attached for 32 and 64 bit systems
SHA256 sums:

b3c6f16be99b04362205c89bc0af9cbb685237c79b9042dafc26f55ea1c581e2  shallowblue_x86-64.exe
1c4219bf3282ce7f1b8ed0050c7011ea576682fde88cd9e147d0c83d8d80e236  shallowblue_x86.exe

v1.0.3

This release fixes some major bugs that were seriously affecting playing strength.

• Fix wrong flag being set in Transposition table during negamax calls
• Fix incorrect move ordering for promotions
• Fix off by one error affecting alpha-beta pruning
• Change how the principal variation is collected during search
• Search to a depth of 6 plys by default
• Add nodes output to UCI info
• Add Windows build script for easy cross compiling on Linux

MinGW Windows binaries are attached for 32 and 64 bit systems:

SHA256 sums:

bfa7be3f8c484b50426235b0fe4f71925ca22b2a99220a23024883d5cc3fb1e0  shallowblue_x86-64.exe
344acd951b74231439c3b73944664bc69c5962de115d9583a08c1b3df7c305f9  shallowblue_x86.exe

v1.0.2

• Add perft command
• Add logo
• Inform the user when they run a debug build
• Clean up Makefile

MinGW Windows binaries are attached for 32 and 64 bit systems.

SHA256 sums:

1eb8b3702cfa3deba09acb87fd59dd5f97fd0620be154d690aee735b26de39e4 shallowblue_x86-64.exe
175e572accb955c490bbecefba56060b35467bb9cfd265112215e558b3605f23 shallowblue_x86.exe

v1.0.1

Performance improvements and bug fixes

• Don't use GCC parallel mode (The extra overhead was slowing down move generation and the parallelism didn't counteract it)
• Fix incorrect MVV/LVA move ordering
• Pre reserve space in the MoveGen class's internal MoveList vectors before filling with moves
• Small cleanups / performance improvements

MinGW Windows binaries are attached for 32 and 64 bit systems.

SHA1 sums:

22045363ca32d42dddc03606860e33ac81be61fa shallowblue_x86-64.exe
63642a14326303ce507df3e2f97c19148999a776 shallowblue_x86.exe

v1.0.0

Initial Release

Ridiculous amounts of coffee were consumed to get to this point.