Author: Robert Hyatt
Date: 07:22:09 09/24/99
Go up one level in this thread
On September 24, 1999 at 01:12:06, Christophe Theron wrote: >On September 23, 1999 at 23:12:48, Normand M. Blais wrote: > >>On September 23, 1999 at 22:44:01, leonid wrote: >> >>>On September 23, 1999 at 14:11:57, Normand M. Blais wrote: >>> >>>>On September 22, 1999 at 15:30:36, Brian Nielsen wrote: >>>> >>>>> >>>>>Hi >>>>> >>>>>My name is Brian, i was thinking about writing a chess engine for fun. >>>>>I am pretty experienced programmer/developper(c++,delpie), but have not been >>>>>programming games, thoug i have made a packman clone a couple years ago. >>>>> >>>>>I have done a little research myself to get the principles in making a chess >>>>>engine/program, and i think i now have basic understanding in how to(i hope :-)) >>>>> >>>>>i am curious in how you chessgame programmers represent the chessboard, I have >>>>>seen 4-5 different examples/ways in how to do it, how do you do it and why ?? >>>>> >>>>>Second how long time does it take to make a basic engine! from scratch >>>>>provided that i am a experienced programmer. >>>>> >>>>>Best regards >>>>> >>>>>Brian Nielsen >>>> >>>> >>>>Hi, >>>> >>>>I'm not using C/C++ (yet) but I thought I could share the idea that I use for >>>>my chess program. It is probably not new but I've nerver seen it mentionned any- >>>>where. It is easy to understand and to implement. So, just for the record, here >>>>it is. >>>> >>>> >>>> >>>>preliminary notes: The lower bound for array indexing is 1 (not 0) in the >>>> explanation below. >>>> >>>>1- The board is represented by an array of 64 integers. >>>> >>>> >>>> >>>> 1 2 3 4 5 6 7 8 - 8 >>>> 9 10 11 12 13 14 15 16 - 7 >>>> 17 18 19 20 21 22 23 24 - 6 >>>> 25 26 27 28 29 30 31 32 - 5 >>>> 33 34 35 36 37 38 39 40 - 4 >>>> 41 42 43 44 45 46 47 48 - 3 >>>> 49 50 51 52 53 54 55 56 - 2 >>>> 57 58 59 60 61 62 63 64 - 1 >>>> >>>> A B C D E F G H >>>> >>>> >>>>2- A 64 by 8 integer array is used for the piece movements. For each square, >>>> 8 directions is recorded: >>>> >>>> >>>> NW(8) N(1) NE(2) >>>> \ | / >>>> W(7)--- ----E(3) >>>> / | \ >>>> SW(6) S(5) SE(4) >>>> >>>> For a given square and a given direction, the index of the adjacent square >>>> is stored. If there is no square (case of a border square), 0 is stored. >>>> >>>> directions: 1 2 3 4 5 6 7 8 >>>> --------------------------------------- >>>> square(1) = 0, 0, 2,10, 9, 0, 0, 0 >>>> square(2) = 0, 0, 3,11,10, 9, 1, 0 >>>> . >>>> . >>>> . >>>> square(64) = 56, 0, 0, 0, 0, 0,63,55 >>>> >>>> >>>>3- The movement of the pieces are defined in term of directions: >>>> >>>> Rook --> 1 to 7 by 2 >>>> Bishop --> 2 to 8 by 2 >>>> Queen --> 1 to 8 by 1 >>>> King --> 1 to 8 by 1 >>>> >>>> Knight --> {1,1,2},{1,1,8},{3,3,2},{3,3,4}, >>>> {5,5,4},{5,5,6},{7,7,6},{7,7,8} >>>> White: >>>> pawn move one --> 1 >>>> pawn move two --> {1,1} >>>> pawn captures --> 2,8 >>>> >>>> Black: >>>> pawn move one --> 5 >>>> pawn move two --> {5,5} >>>> pawn captures --> 4,6 >>>> >>>>4- Enhencements. >>>> >>>> A 64 by 8 array can be generated for the knight where the squares stored >>>> for a given direction is the end square of a knight move. Then the knight >>>> movement can be defined this way: >>>> >>>> Knight --> 1 to 8 by 1 >>>> >>>> >>>> >>>>Best Regards, >>>> >>>>Normand M. Blais >>> >>>This is pretty fascinating for me to find your description of the chess >>>board. It had nothing to do with mine. My question to you is: Do your >>>representation of the board is usual? >>> >>>Thanks, >>>Leonid. >>>boad represention is usual one or something >> >>The way I represent the chess board is not new. What's particular is the way I >>generate the moves using an intermediary array to represent directions. I was >>able to build a movegenerator in a short time. I compare it to TSCP move >>generator and it is as fast if not faster. I know that the bitboard is the way >>to go but I'm using an interpreted language that don't have 64bits unsigned >>integer data type. I'm programming for fun only. >> >>NMB > >If somebody tells you bitboards are the way to go, don't believe him. > > > Christophe When IA64 is a reality, bitboards are the way to go. :)
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