Author: Tony Werten
Date: 15:24:02 01/07/03
Go up one level in this thread
On January 07, 2003 at 16:27:33, Russell Reagan wrote: >On January 07, 2003 at 16:05:06, Tord Romstad wrote: > >>I still don't quite understand this, I'm afraid. How do you determine the >>lowest attacking piece from your bit settings in the presence of an x-ray >>attack? How do WB[G8] look for the above two positions? The way I understand >>the section about Rebel's eval on your homepage, the bit vector would look like >>this in both cases: >> >>+------+------+------+------+------+------+------+------+ >>| BIT0 | BIT1 | BIT2 | BIT3 | BIT4 | BIT5 | BIT6 | BIT7 | >>+------+------+------+------+------+------+------+------+ >>| Number of | PAWN |KNIGHT| ROOK | QUEEN| KING | >>| ATTACKERS | |BISHOP| | | | >>+------+------+------+------+------+------+------+------+ >>| 0 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | >>+------+------+------+------+------+------+------+------+ >> >>Clearly I am misunderstanding something, but I am not sure what ... >> >>Tord > >I am with you on this one. I don't understand it either. For example, if you >switch the white queen and bishop that are doing the attacking, the bit vector >is unchanged. If you pass that into the TABLE[][][] that Ed described, you >should get the same 'status' regardless of which piece is doing the "real" >attacking and which piece is doing the x-ray attack, and that's not going to be >very useful. > >So I too am missing something, and I too am not sure what... I'll give a different explanation. I thought Ed didn't want to give the full solution to leave some puzzling, but appearantly he didn't really know either anymore. What you do when a smal piece attacks trough a high piece is, you count from that moment on as if it is the big piece that's doing the attacking. So you OR with the big piece (useless because the big piece will also be ORed later) AND ad one to the attackers. When it's high through low, you just go on ORing with the high piece. This seems incorrect, but since you won't try the high piece until the small pieces are gone, it doesn't matter. So: high through low: count as normal attack low trough high: count as an attack made by high. Tony
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.