Changelog
Last modified: 2/17/07
Prophet 2.0 (2/17/07)
- added additional semaphore to remove race condition in pondering
- timing adjustment: won't start new iteration if more than half
of soft time limit has been used
- minor eval tweaks to pawn pst and king safety
- null search now r=2/3, depending on search depth and material
- modified ics output to be less verbose
- bugfix: only 1/1000 of a second was being alloted for every 1 sec increment
Prophet 2.0.epsilon.2 (11/30/06)
- now utilizing single search thread for the life of the program, as opposed
to creating/detaching as needed. Much cleaner...
Prophet 2.0.epsilon.1 (10/31/06)
- symmetry debug code in eval (no bugs found!)
- checks in qsearch
- database backend (hardly used yet)
- pruning in qsearch when capture can't raise score to within 1/2 pawn of alpha
- improved aspiration window bounds
- implemented principal variation search (pvs)
- fixed i/o bug: would occasionally lose on time due to input being buffered
- switched to SAN
- added 'lack of material' to IsDraw() function
- modified search to consider a position visited even once before as a draw
- futility pruning, extended futility pruning
- late move reductions
- implemented Winboard easy/hard commands
Prophet 2.0.delta.1 (8/18/06)
- pondering (threaded implementation)
- improved mobility routines (now they exclude squares occupied by friendlies)
- improved speed of LeastValuable in SEE (thanks to Charles Roberson)
- tweaked recap extension (now insists successive captures to SAME square)
- bugfix: was storing search value in hash lower bound entries, now beta
- added depth preferred hash table (uses half the total hash space)
Prophet 2.0.gamma.1 (8/13/06)
- Null move forward pruning (r=2)
- Simple opening book
The opening book is very simple at present. It was added hastily for use in the ACCA tournament.
You can create a book from a single PGN file as follows:
./prophet_2 pgntobook=../pgn/somepgn.pgn
which will result in the creation of book.dat in the ../book directory (parallel to the src directory).
Note that any future use of pgntobook will clobber your existing book.dat! Also important to note
is that the move selection is done in a (weighted) random fashion among moves that were played
at least 10 times.
Solves 225/300 WAC problems at 1 second and 259/300 at 5 seconds on a 2.4 GHz p4.
Solves 751/1001 WCSAC problems at 1 second on a 2.4 GHz P4.
Prophet 2.0.beta.5 (8/13/06)
- add real evaluation (though simple and not well tuned)
- aspiration windows
- passed pawn extension (disabled)
- recapture extension
- fixed bug in ParseMove() : long and short castles being parsed
incorrectly. (o-o -> long castle, o-o-o -> short castle!)
- improved move ordering through history heuristic and other minor tweaks
- pruning losing captures in qsearch using SEE
- added soft/hard time limits. hard used to resolve fail low at root
Solves 213/300 WAC problems at 1 second and 249/300 at 5 seconds on a 2.4 GHz P4.
Solves 734/1001 WCSAC problems at 1 second on a 2.4 GHz P4.
Prophet 2.0.beta.4 (7/19/06)
- move ordering: separated capture/noncapture move generation,
playing captures first
- move ordering: 2 killer (noncapture) moves
- eval: isolated pawn penalty
- separate move ordering function for check evasion
- added SEE (but unused for now)
Solves 212/300 WAC problems at 1 second and 252/300 at 5 seconds on a 2.4 GHz P4.
Solves 663/1001 WCSAC problems at 1 second on a 2.4 GHz P4.
Prophet 2.0.beta.3 (7/7/06)
- Added (fractional) extensions: one reply and check
- Bugfix: "exact" mate scores from hash were being wrecked
- Bugfix: illegal move was possible after a check
Solves 183/300 WAC problems at 1 second and 210/300 at 5 seconds on a 1.6 GHz Centrino.
Solves 175/300 WAC problems at 1 second and 205/300 at 5 seconds on a 2.4 GHz P4.
Prophet 2.0.beta.2 (6/26/06)
- Added simple quiescence search
- Added transposition table with "always replace" replacement strategy
- Fixed division by 0 bug that occurred when computing the NPS for very quick searches
Solves 135/300 WAC problems at 1 second and 158/300 at 5 seconds on a 2.26 GHz P4.
Prophet 2.0.alpha.3 (6/3/06)
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