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Subject: Re: Alpha-beta PV collection

Author: Andrew Wagner

Date: 07:47:00 02/18/04

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On February 18, 2004 at 08:54:44, Charles Roberson wrote:

>
>  Fundamentally, it creates a pv line at each ply. Then when best move is
>changed at ply p it does 3 things:
>    1) save the best move at the head of the pv for this ply
>    2) save the length of the pv
>    3) copy in the pv for ply p+1 after the best move for ply p in the line
>       for  ply p.
>
>   The idea takes advantage of how the search works. When you get a value better
>than alpha (a new best move), you have searched the tree below. So, you just
>need to chain the best moves together. One way to do this is above. How it works
>is this:
>     when searching a 4 ply depth and updating the best move at ply 2, you have
>  searched below ply two to plys 3 & 4.
>    1) at ply 4 (you do this first in a depth first search), you put in the
>       best move for ply 4.
>    2) you get a new best move for ply 3, you put it in the pv line for ply 3
>       and copy the pv line for ply 4 which is only one move.
>    3) you get a new best move for ply 2, you put it in the pv line for ply 2
>       and copy the pv line for ply 4 which is now 2 moves.
>
>    You are asking a lot of questions at a fast pace. Is this a school project?
>
>    Charles


Ok, I think I understand. Will try to fool around with it this weekend some. And
no, it's not for a school project. I decided I wanted to test my programming
skills as well as do something that could possibly impress potential employers.
So...I wrote a chess program in one week in a language I've only been studying
for a few months :)  Some of the chess-specific stuff is pretty hard though.



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