Author: Vincent Diepeveen
Date: 10:56:29 09/25/99
Go up one level in this thread
We should compare speeds.
What i do after 1.e4,e5 2.d4,d5 is
generate the move list a few million times (n times).
Then i divide the time by (n * #semi legal moves).
#nodes a second generated at a PII450 for diep is 15.5M
Haven't seen anyone faster so far, though most are not
reveiling their speed.
Note that if we have a merced within say 5 years that i
can implement bitboards for a few eval terms within a day by then.
No need for rotated bb of course as i keep my current generator
and makemove.
Majority of code is not faster using bitboards even at 64 bits
machine.
On September 24, 1999 at 10:22:09, Robert Hyatt wrote:
>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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