Author: Bas Hamstra
Date: 01:12:01 11/10/99
Go up one level in this thread
Hi,
Don't worry about that 64 unused entries. If you want to be fast you not only
have to pay attention to fast move generation, but especially to fast capture
generation and fast attack generation. For all that your 0x88 reprensentation is
fine.
It is also fine because you can see very fast if a piece (pseudo-) attacks
another piece, without scanning squares. You can do that by square relationship
testing and it is very fast.
Just subtract two squares, add an offset and lookup the result in a simple
array.
Regards,
Bas Hamstra.
n November 09, 1999 at 22:29:17, Nicolas Carrasco wrote:
>Dear Guys,
>
>I have tryed to build a move generator using a single a array faster than TSCP.
>(I know how to increase a bit TSCP gen), and it seems that for move-generator is
>better a pair of arrays, but I guess to know if it is the same or equal speed
>for an eval function. I know that this depends of how you do that ,but try to
>answer considering your experince.
>
>Maybe a pair of 64 int arrays is slower than a single one for eval functions
>and/or hashing functions.
>
> I am asking you this in order to select the apropiate board representation for
>a long time before going to bitboards.
>
>I also found an interesting board representation that uses this:
>
>{ 0, 1, 2, 3, 4, 5, 6, 7,
> __, __, __, __, __, __, __, __,
> 16, 17, 18, 19, 20, 21, 22, 23,
> __, __, __, __, __, __, __, __,
> 32, 33, 34, 35, 36, 37, 38, 39,
> __, __, __, __, __, __, __, __,
> 48, 49, 50, 51, 52, 53, 54, 55,
> __, __, __, __, __, __, __, __,
> 64, 65, 66, 67, 68, 69, 70, 71,
> __, __, __, __, __, __, __, __,
> 80, 81, 82, 83, 84, 85, 86, 87,
> __, __, __, __, __, __, __, __,
> 96, 97, 98, 99, 100, 101, 102, 103,
> __, __, __, __, __, __, __, __,
> 112, 113, 114, 115, 116, 117, 118, 119 } // THE MAP TO CALCULATE THE VECTORS
>
>int initial_board[120]=
>{
> BR, BN, BB, BQ, BK, BB, BN, BR,
> __, __, __, __, __, __, __, __,
> BP, BP, BP, BP, BP, BP, BP, BP,
> __, __, __, __, __, __, __, __,
> XX, XX, XX, XX, XX, XX, XX, XX,
> __, __, __, __, __, __, __, __,
> XX, XX, XX, XX, XX, XX, XX, XX,
> __, __, __, __, __, __, __, __,
> XX, XX, XX, XX, XX, XX, XX, XX,
> __, __, __, __, __, __, __, __,
> XX, XX, XX, XX, XX, XX, XX, XX,
> __, __, __, __, __, __, __, __,
> WP, WP, WP, WP, WP, WP, WP, WP,
> __, __, __, __, __, __, __, __,
> WR, WN, WB, WQ, WK, WB, WN, WR
>
>};
>
>BP,WP,....,..., are number definitions :)
>
>the "__" are elements are not being used.
>
>here I skip the mailbox check doing :
>
>#define BOARD(z) ((z&0x88)==0) /* To check if a position z is inside
>the board */
>
>So if I put
>gen()
>{
> if(BOARD(any_position)) /// I SAVE THE MAILBOX FUNCTION
> THIS IS A LEGAL MOVE
>}
>
>The problem that I founded here is that I have to eat 64 unused
>elements or run an if statement to skip them, and that slows too much.
>
>Thanks
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