AmigActive 10/AACD 10.iso/AACD/Games/PhalanxXVIII/README

Text File | 1998-09-06 | 20KB | 317 lines

Phalanx is a chess playing program
Copyright (c) 1997, 1998 Dusan Dobes

LICENSE AND WARRANTY
- Phalanx is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2, or (at your option)
  any later version.
- Phalanx is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
  along with Phalanx; see the file COPYING.  If not, write to
  the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  MA  02111-1307, USA.

WHERE TO GET PHALANX
  ftp://sunsite.unc.edu/pub/Linux/games/strategy/    (and mirrors)
  ftp://ftp.math.muni.cz/pub/math/people/Dobes/

COMPILING, PORTABILITY
  Compiling is simple, at least under Linux. Just type `make'.  Phalanx is
  developed under GNU C, GNU Debugger, and GNU Make.  It's probably possible to
  compile it on many different platforms, but today i have no oportunity to try
  it on any other platform than Linux and HP-UX.  If your system does not
  support GNU exensions (e.g. long options), remove '-DGNUFUN' from DEFINES in
  makefile.  If you have incompatible 'make', try this:
  $ cat *.c > allphalanx.c; cc -O allphalanx.c -o phalanx

INTERFACE, COMMAND LINE OPTIONS
  Phalanx is xboard compatible.  Running with xboard: 'xboard -fcp phalanx'.
  Note that permanent brain (pondering) is off by default.  Newer versions of
  xboard set it on with the 'hard' command.  If this does not work, try
  'xboard -fcp "phalanx -p+"' or (for <4.0.0 versions of xboard) change your
  initString (see Xboard documentation for details).  It's better to stop
  permanent brain in both programs, when playing Phalanx against another
  program on a machine with one CPU.
  It's also possible to run phalanx without xboard. Do "phalanx -h" to get
  a list of command line options. One important command of phalanx's ASCII
  interface is "help".

MORE ABOUT INTERFACE
  I'm trying to write an interface that fits following three requirements:
  - Xboard compatibility.  For best results, get the latest version of Xboard.
  - shell-like interface that allows running commands in a batch. It's very
    useful for testing. Example: look into the file test.fin. It's a set
    of chess problems and solutions. You can simply send this file to
    Phalanx's stdin:
    $ phalanx -c+ -o- -b- -f10 < test.fin | tee result
    ( Where: -c+ .... use cpu time
             -o- .... don't use polling input
             -b- .... no opening book
             -f10 ... fixed time 10 seconds per move )
    Watch how it works.
  - Acceptable ASCII interface.

OPENING BOOK
  From version VI, there are two book files - primary (pbook.phalanx), and
  secondary (sbook.phalanx).  You can specify book directories via command line
  (-P, -S) or use environment variables PHALANXPBOOKDIR and PHALANXSBOOKDIR.
  Otherwise Phalanx tries to find its book files in current directory
  (./book.phalanx, ./sbook.phalanx) and finally in compiled-in directory
  (/usr/local/lib/phalanx).  You can change the compiled-in directory in
  makefile.
  - pbook.phalanx is 'hand'-written, text book.  One line per position, sorted.
    This time, it's bigger than really needed, because it was the only book
    file till version V.  The size will be smaller and the line format might
    change to EPD+SAN in future.
  - sbook.phalanx is binary book, generated from large PGN files.  Six bytes
    per move (4 hash key, 2 move).  You can generate your own sbook.phalanx
    with 'phalanx bcreate', like this:
    $ ./phalanx bcreate < manyGMgames.pgn
    or:
    $ ./phalanx bcreate 1250000 < manyGMgames.pgn
    ( where 1250000 is internal buffer size in cells.  One cell takes 12 bytes.
      Bigger is better, only if it's too big a part of the buffer is unused.
      E.g. 1250000 is enough to parse Crafty's 'medium' book source - 29MB. )
  A position is first searched in pbook.phalanx.  Only if it's not found there,
  sbook.phalanx is searched.

INSIDE THE MACHINE
  Phalanx uses (traditional) 10x12 board implementation.  There are three
  often used board implementations: "8x8" (GNU Chess), "bitboard" (Crafty),
  and "10x12" (Nimzo, Phalanx).  In short, "10x12" is easy to implement and
  the code and basic data structures are small ( == fast on PC).  The engine
  uses many well known techniques: PVS (principal variation search),
  transposition/killer table, static-eval cache, history killers, SEE (static
  exchange evaluator), null move pruning, forward pruning, internal iterative
  deepening, chess-specific extensions.

AUTHOR
  Dusan Dobes, [e-mail]


HISTORY
The rest of this file is history of Phalanx.

I         First version to play a legitimate game, it finally knows all rules.
19970304  I spent a lot of time on tuning transposition table code and
          extensions. The program scores 78% at large Reinfeld's test set, 10 s
          per move, on 486+/150.

II        Two killer heuristics added: well known history killers (modified)
199704??  and `reaction' killers (the killer is connected to the previous enemy
          move). The tree search is faster, especially at `quiet' positions.
          Hashtable presearch. Modified hashentry replacement strategy. Better
          evaluation function, it now knows more about passed pawns, the
          endgame play is much stronger. Fixed bug at 7-th row pawn push
          extension routine. Faster output - using sprintf() to prepare the
          output and then only one printf. New command line options: -t, -T to
          set the hashtable size.

III       Permanent brain (pondering).  King safety evaluation.  Hung pieces
19970529  static evaluation.  Null move pruning.  Forward pruning.  Better time
          heuristics - forced moves are played quickly.  New cmd-line options:
          -f, -x, -p, -s.

IV        New option -c to determine whether to use cpu or real time.  The
19970721  internal timing resolution changed to 1/100 of a second.  Xboard
          compatible editing position.  Removed en-passant capture from
          quiescence search.  Changes in static-eval function.  Piece list
          implemented - speedup is between 0 and 20%; more in endgame.  Pinned
          pieces static evaluation.  Better evaluation of weak pawns.  Trapped
          bishop and knight evaluation.  Bugfix at extending check evasions.
          Bugfix: development bonus was computed but not added to total
          evaluation.  Output change: '!' means turn, '!!' means value out of
          window.

V         Mostly interface changes, no big improvement in playing strength.
19970803  Xboard compatibility fixes: 'post' is no more switch, new command
          'remove'.  Fixed command 'level': 'level 0 5 0' (five minutes per
          game) should work, also increment (ICS) levels ('level 0 2 12').
          Increment can be given at command line.  New option -o (polling
          input) - when running tests, phalanx needs -o-.  New feature of
          autotesting: all incorrect results are written into file
          'notfound.fin'.  Small output changes for better compatibility with
          xboard 3.6.2.  Eliminated some bad turns in evaluation.  Better king
          safety evaluation - counting safe checks available.

VI        Fixed small efficiency bug in evaluate.c.  Improved time heuristics
19970915  for increment (ICS) levels.  Optimized hashing - about 5% overall
          speedup.  Fixed bug in ptime().  User is now allowed to continue play
          even if the position is drawn by 3-rep., material, or 50 moves rule.
          Fixed bug - Draw requests are now always ignored, not always accepted
          :-).  Xboard-compatible 'Illegal move' message.  Binary opening book,
          created from PGN by bcreate.  This distribution is bigger than any
          previous because it contains a small example of binary book
          ('sbook.phalanx', 174kB, 29634 moves).  SAN input accepted.  Static
          evaluation now better understands middlegame positions without
          castling.  Added pre-computed tables into static evaluation -> about
          5% speed improvement.  'Show thinking' mode now shows also a list of
          book moves if there's a book entry.  I have played a match with
          previous version (64 games, 2 minutes, increment 12 seconds, on
          a 486+/150, via xboard, no pondering), new version wins 38.5-25.5.

VII       Courtesy of Pavel Janik ml., new command 'fen'.  Bugfix in command
19971022  line parser, 'phalanx 0 2 12' now works.  Better time controls: added
          hard time limit to avoid being flagged.  Pondering bugfix: Phalanx
          was pondering O-O, but opponent played O-O-O; the move check was
          incorrect and Phalanx thought that O-O was played; this resulted in
          'Illegal move' message few moves later.  More pondering safety: the
          move to be pondered is now checked for legality, before this fix it
          was simply taken from PV (if present), but PV is not always 100%
          correct.  More PV safety: search cannot be interrupted during the
          first iteration, the abort is delayed until the first iteration is
          finished.  New options: -r <resign value>, -b <+/-> to set opening
          book on/off.  New commands hard/easy to set pondering on/off.
          Optimized do_move(): 3% speedup in test positions.  Search
          optimization: null move is not played if the value in hash table
          entry is too low.  Output bugfix: output is now readable even at long
          time searches.  SEE (Static Exchange Evaluator) and more pruning in
          quiescence search.  RoboFICS compatible commands 'white' and 'black'.
          Routine for evaluating pawn endgames.  New extension trick that helps
          in some horizon-effect type positions, it's based on measuring
          difference between current score and null move result; if current
          score is much better, the side to move must be under threat and the
          line is extended, similar trick is also in gnuchess.

VIII      Fixed bug in search(): eliminated useless re-searches -> about 3%
19971103  speed improvement.  Noise level is now in centiseconds, not in nodes.
          Improved horizon-effect extensions.  endgame.c: new endgame
          knowledge, mostly for endgames with minor pieces and pawns: knight
          and bishop mating, knight+knight (draw), minor vs. minor (draw),
          minor vs. pawn (draw, but still needs some work, sometimes a pawn
          wins against a knight), onepawn() as a special case of pawns(), bad
          bishop (bishop + rook pawn), basics for R+P vs. R, bishops with
          opposite colors (this is often drawish ending).  New penalty for
          moving castling-side pawns in middlegame.

IX        Function smove() is now used in both binary book and hashing code, it
19971205  is cleaner and easier to read, the binary is smaller with this.
          Bugfix: Phalanx now does not ponder move that leads into a terminal
          position (checkmate, stalemate), this fixes some unexpected quits
          (I hope all of them).  Added more limits to horizon-effect extension
          trigger - there was so many extensions, that version VIII was
          actually weaker than previous versions, because of lower nominal
          search depth; these extensions are now used only for major threats.
          Static eval cache entry is now packed into 4 bytes instead of 8 ->
          the cache eats only 256K (512K before this).

X         Bugfix in static evaluation of trapped knight at [AH]7.  Better
19980108  evaluation of trapped bishop ([AH]7) and knight ([AH][87]), now it's
          using the static exchange evaluator.  Time allocation: alloc more
          time (+1/8) if pondering is on.  Better understanding of 'trade-down'
          bonus - if there are no pawns, you often need a rook more to win the
          game, a minor piece is not enough.  Shallower extensions resulting in
          greater average search depth.  Easy levels: use new command line
          option -e <1...100> to select an easy level; 1 is the strongest and
          100 is the easiest one, Phalanx tries to make human-like blunders.
          Minor changes in resigning.  Clean up in pbook.phalanx, deleted over
          100 positions.  Killer heuristics now uses the SEE.  Bugfix in
          endgame.c: trade bonus did not work for kings and pawns endgames.
          Simple learning, can be activated by -l+ option; it is off by
          default, because it's very experimental version.  New version wins
          engine-engine match with version IX 23:17 (tc 2, inc 8, 486+/150,
          no learning, no pondering).

XI        Courtesy of Milan Zamazal: long options and user-friendly handling of
19980125  book files - you can now use environment variables or command line
          options.  Bugfix in trade bonus: endgame KQ-KBPP was evaluated only
          about +1.10, but the stronger side is winnig here even without pawns,
          now it's >+3.00 and Phalanx can solve this Dufrense&Mieses study:
          8/3Np3/7P/1p3P2/1k6/5K2/1b6/8/w Pf5f6.  Deeper overall extensions,
          +10% of ply.  More check evasion extensions.  Wider window for 'lazy
          evaluation', search is now slower but stable.  Minor fixes in forward
          and null move pruning.  Zero-width search modified for root moves,
          actually it's no more zero-width; this eliminates some 'blind turns'
          (a move is evaluated as >=(Alpha+1), but the engine cannot prove it
          in re-search in full [Alpha,Beta] window).  Minor changes in static
          evaluation.  Bugfix in time allocation of increment levels.  Changed
          time heuristics to use more time.

XII       More pruning in quiescence search: moves that have little chance to
19980301  return the value over alpha are not generated.  Permanent brain is
          now really 'permanent', if there is no move to ponder in the PV,
          Phalanx uses short search to pick a move and ponders it.  Bugfix:
          occasional zero division at very fast time controls, like 10s/game.
          Some puts() replaced with printf(), puts() is buggy in my gcc (2.7.2)
          and causes sigsegv when interrupted and called again during the
          interrupt.  Optimized null move, this speeds up the engine.  Easy
          levels now use nodes instead of centiseconds for measuring time, the
          playing strength of easy levels does not depend on cpu power and
          cpu load.  Resigning now works with RoboFics (via 'tellics resign').
          Updated FSF address in docs.

XIII      Lots of 'char' and 'short' replaced with 'int' -> speedup on iX86
19980316  chips (about 10% on my 486, probably more on P6).  Bugfix at 'edit'
          command, edit was broken for positions with black to move.  New
          command line option 'bench', 'phalanx bench' runs a 5 cpu-minutes
          benchmark and reports nodes per second.  Added some interesting lines
          into the opening book.  Dynamic draw score, it's set to -20 by
          default.  New command 'rating <phalanx rating> <opponent rating>' to
          adjust the dynamic draw score, Phalanx tries to avoid draw with
          weaker opponents, minimal draw score is -20, maximal +20.

XIV       Dynamic draw score did not work for stalemate, now fixed.  Major bug
19980416  fixed at resigning: if resigning was on, phalanx resigned almost any
          game after few moves, this was broken from previous version.
          Simplified computing bounds for lazy evaluation, this was too
          complicated and slow.  Higher material limit for evaluating position
          as endgame.  Deeper extensions, +0.1 ply.  Improved move ordering at
          root search.  Minor optimizations.  More variability in opening book.
          Disabled scout search near leafs.  Bugfix: type of Nodes changed to
          'long long' (64 bits on Intel[3456]86), 32-bit integer was not long
          enough for >24 hour runs.  Bugfix: option -P did not work, now fixed.
          Added startup messages that show full path of all open files.

XV        Internal iterative deepening.  Cleaned pbook.phalanx.  New "Pc2-c4"
19980614  code to encourage playing c4 (c5 as black) in closed positions where
          e4 (e5) is not possible.  Bugfix at computing total material on the
          board, the variable was sometimes overwritten with unexact value.
          New xboard compatible commands 'bk' and 'analyze'.  'bk' shows all
          book moves.  'analyze' starts analysis mode.  Bugfix in bcreate.c: no
          games on stdin caused segmentation fault.  GNU extensions (long
          options and snprintf) are now used only if GNUFUN is defined
          (-DGNUFUN in makefile).  New endgame knowledge: KNP vs. K is
          sometimes draw.  Small changes in static evaluation.  SIGINT is
          ignored in polling input mode.  Time information in post lines is
          shown in centiseconds instead of seconds to follow current draft of
          xboard chess engine communication protocol.

XVI       Bugfix in analyze mode: there is no extra character after the search
19980630  depth number in post lines - xboard understands that time info is in
          centiseconds, not in seconds.  Bugfix in null move pruning: the side
          that is trying its second move in row must have at least one legal
          move, this caused segmentation fault if there was none.  Command
          'hard' does not set pondering on in easy levels.  Bugfix at parsing
          SAN moves, nc3 was (possibly) interpreted as Pc2-c3.  Command 'level'
          accepts time in mm:ss form, for example 'level 0 2:30 12'.  Bugfix in
          kings+pawns endgames - penalty for pawns on one file (doubled) worked
          as penalty for pawns on one row.  Improved kings+pawns endgames
          static evaluation.  New command 'xboard' sets xboard compatible mode.

XVII      More variability in pbook.phalanx.  Better sbook.phalanx, generated
19980804  from wall.pgn.  Changed (and fixed) extensions for check evasions and
          passed pawn pushes.  Changed evaluation of passed pawns.  phalanx and
          bcreate integrated into one binary, most of the code was common
          anyway; book can be created via 'phalanx bcreate' instead of just
          'bcreate'.  Bigger limit for count of [position,move] in bcreate
          code, the counter has 32 bits instead of 16.  Performance bugfix in
          null move pruning.

XVIII     Bugfix in the static exchange evaluator - it let kings slide
19980906  horizontally.  New styling of board in command "bd"/"d".  New command
          in edit mode: 's' to switch side to move.  Modified look of edit
          mode.  Modifications in static evaluation: bishop pair needs
          mobility; queen has 'king distance' bonus only if it's on a safe
          square; simpler rook evaluations - smaller bonuses; forpost (outpost)
          pawn gets more bonus for # of pieces defending it (Aaron Nimzowitsch,
          "Mein System"); bigger bonus for protected or connected passed pawns.
          Modified threat extensions - only mate threats are extended.  Bugfix
          in analysis mode: PV is computed (and shown) even if there is only
          one legal move.  New feature of command 'level' - 'level N' sets
          level to N seconds fixed time per move.  Better pbook.phalanx.