Phalanx is a chess playing program
Copyright (c) 1997, 1998, 1999, 2000, 2014 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

- http://sourceforge.net/projects/phalanx/
- ftp://sunsite.unc.edu/pub/Linux/games/strategy/   (Only sources)

  Please let me know if there are others, i will update this list.
  Feel free to put Phalanx on your ftp site.


COMPILING, PORTABILITY

  Compiling is simple, at least under Linux. Just type `make'.  You might want
  to edit the optimization flags in makefile to produce faster binary.  Phalanx
  is developed under GNU C, GNU Debugger, and GNU Make.  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.


COMMAND LINE OPTIONS

  Usage:
    phalanx [options] [<moves> <minutes> [<increment in seconds>]]
    phalanx [options] [<seconds per move>]
    phalanx bench
    phalanx bcreate [book creation options]

  Options:
    -t <transposition table size in kilobytes>
       Transposition table really needs to fit in the RAM memory, it should
       never be swapped to disk. Maximum size is your total RAM minus space
       needed for OS (8-20 MB) minus space for other (possible) applications.
    -f <fixed search time in seconds>
    -x <+/->  xboard mode on/off                  default: on
       "Xboard mode off" is designed for the ascii interface. In -s+ mode it
       shows also the move that is currently searched.
    -p <+/->  permanent brain on/off              default: off
       Phalanx ponders on a predicted move with the permanent brain on. It is
       sometimes called pondering. Xboard sets it on with the 'hard' command
       regardless of this option, just use xboard menu to set it on/off.
    -s <+/->  show thinking on/off                default: off
       Phalanx shows depth, evaluation, time used in centiseconds, nodes
       searched, and principal variation (best line) when searching. Xboard
       overrides this option with 'post' and 'nopost' commands, just use
       xboard menu instead of this.
    -c <+/->  cpu time                            default: off
       This one defaults to the "wall clock" real time. It's better to use
       the CPU time when running test suites.
    -o <+/->  polling input                       default: on
       Use -o- for running test suites. Phalanx reads the positions from its
       standard input and polling input makes it stop thinking after almost
       zero seconds on each position.
    -b <+/->  opening book                        default: on
    -l <+/->  learning on/off                     default: off
    -r <resign value in centipawns>               default: 0 (no resigning)
    -e <easy level 0...99>                        default: 0 (best play)
       1 is the hardest and 99 is the easiest easy level. Phalanx tries to
       emulate human-like blunders, the higher the number the more blunders it
       plays. It also adds more randomness with the easy levels, repeating
       games should be impossible. Easy levels set hashtable size to zero,
       pondering and learning to off. Since version XXIII, Phalanx uses
       the time normally, it does not respond immediatelly. NPS is lowered
       to 100-300, unless overriden by the -n agrument. Root moves randomizing
       is used here as well, between 10 to 60 centipawns, unless overriden
       by the -z argument.
    -z <random evaluation in centipawns>          default: 0 (best play)
       Randomize play. Add pseudo-random values to root moves evaluations.
       The numeric value limits the random range, the interval of random
       evaluations to be added is [-N/2 ... N/2].
    -z <random evaluation in centipawns>:<N>
       Like above, but only randomize first N moves. This is to avoid repeating
       lines in opening, while keeping almost the same playing strength. For
       example, -z 20:10 will randomize first 10 moves in the game by
       20 centipawns.
    -n <nodes per second>                         default: 0 (no limit)
       Limits the speed to weaken the engine and to use less resources: The
       speed of the machine does not matter here, it uses usleep() during
       the search, so with low NPS it does not raise the machine load.
    -v
       Print version and exit.
    -P <primary book directory>
    -S <secondary book directory>
    -L <learning file directory>
    -g <log file name>

  Book creation options:
    -b <buffer size in cells>
       Stage 1. One cell is 10 bytes. Twice the space is needed for sorting
       the buffer, use no more than 1/3 of your total RAM.
    -p <maxply>
       Stage 1. Stop parsing the game at given ply (halfmove). Default value is
       70, it's 35 full moves.
    -c <max length of comment>
       Stage 1. PGN files have comments in {}. Phalanx skips the comments when
       parsing. Big PGN files also have lots of errors, sometimes '{' does not
       have matching '}'. So, if the comment goes over the maximal length, we
       suspect the text is no more the comment and continue parsing. Default
       value is 4096 bytes.
    -w <winning move value>
       Stage 1. We are adding the [position,move] to the database. The side to
       move won the game. The appropriate database entry gets <winning move
       value> bonus. Default is 5 points. Use values in 1-10 range.
    -d <drawing move value>
       Stage 1. Same as the previous except that the game was drawn. Default
       value is 2 points.
    -l <losing move value>
       Stage 1. Same as the previous except that the side to move lost the
       game. Default value is 1 point.
    -u <unknown result move value>
       Stage 1. Same as the previous except that there is no result of the game
       in the PGN file, sad and common case. Default value is 1 point.
    -v <min value of move to add>
       Stage 2. Moves that have less total points than this value are not
       added into the sbook.phalanx. Bigger numbers create smaller books.
       The smallest reasonable number is 10. Default is 15.
    -g <min value percentage of best move to add others>
       Stage 2. Use values in 50-100 range. The 2nd, 3rd, and other moves are
       stripped if their value is less than G% of the value of the best move.
       The G is decreased in positions where the 1st move value has high enough
       value to give more variability in frequently played opening, e.g. we
       want a bit more than just sicilian, maybe 1. ... e5 is also good.
       50 gives lots of variability and maybe dubious moves, 100 gives almost
       no variability and only the highest valued moves. Default is 80.

  Note that the book creation does not work with DOS end-of-lines in the PGN
  input, just use dos2unix filter if needed.

  Examples: phalanx -c+ -s+ -o - -x- -f 60 -t4000
            xboard -fcp "phalanx -r800"
            xboard -fcp 'phalanx -e 99'


ASCII INTERFACE COMMANDS

  about            about Phalanx, show version, copyright info, and settings
  bd               display position (same as 'd')
  bk               show book moves (xboard) - shows ECO code/name and all moves
                   from both primary and secondary opening books. The last line
                   is the text string that is used to identify the position in
                   the pbook.phalanx. Primary book moves are shown along with
                   their probabilities. There is no such probability info for
                   the secondary book moves, as all secondary book moves have
                   equal probability.
  book             enable/disable opening book
  both             machine plays both
  depth            set search depth in plies (xboard). Search will be stopped
                   at given depth, no timing info is used.
  fen              display position in FEN
  force            user plays both (xboard)
  go               switch sides, start computing (xboard)
  history          show game moves in full notation
  level N M I      set level to N moves in M minutes, increment I seconds.
                   Phalanx needs its time info have updated from xboard via
                   the 'time' command to make this level work well.
  level N          set level to fixed time N seconds per move
  new              new game (xboard)
  post             show thinking (xboard)
  remove           take back last move, two plies (xboard)
  nopost           do not show thinking (xboard)
  quit             quit (same as 'exit' or end of file character)
  score            show static evaluation
  time <N>         remaining time is N/100 s (xboard)
  undo             undo last ply (xboard; same as 'u')
  <FEN position>   set test position, start search, show result
  #                comment


OPENING BOOK

  From version VI, there are two book files - primary (pbook.phalanx), and
  secondary (sbook.phalanx).  A position is first searched in pbook.phalanx.
  Only if it's not found there, sbook.phalanx is searched.  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 <options>', like this:
    $ ./phalanx bcreate < manyGMgames.pgn
    Book creation has two stages. First stage reads and parses PGN from
    standard input and creates the 'rbook.phalanx' file. If rbook.phalanx
    already exists, the first stage is skipped. Second stage filters positions
    and moves from the rbook.phalanx to sbook.phalanx. First stage needs about
    30 times more time than the second one. Look at 'book creation options' for
    more details on creating your sbook.phalanx.


ECO DATABASE

  From version XX, Phalanx has ECO database.  Command 'bk' can also print ECO
  code and opening/variation name.  This works with xboard 4.0 via
  "Help"/"Book" menu item.  If you want to activate this feature, you must type
  the 'bk' command (or click the "Help"/"Book" menu item in xboard) once per
  session in the initial position.  Then, the ECO index is created (that might
  take few seconds on a slow machine).  The ECO index is based on positions
  rather than on moves so transpositions between openings can take place.  The
  eco.phalanx file is taken from Gnuchess distribution (originally eco.pgn, but
  this is not real pgn).


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

