Author: Uri Blass
Date: 01:42:31 03/23/04
Go up one level in this thread
On March 23, 2004 at 02:00:13, Mridul Muralidharan wrote: >On March 22, 2004 at 19:30:35, Anthony Cozzie wrote: > >>On March 22, 2004 at 17:18:49, Dann Corbit wrote: >> >>>On March 22, 2004 at 16:18:19, Anthony Cozzie wrote: >>> >>>>On March 22, 2004 at 03:40:57, Daniel Shawul wrote: >>>> >>>>>Hello >>>>> >>>>>I have decided to use attack tables. I just did >>>>>a rough implementation of it at the beginning of the eval >>>>>according to Ed's paper. The problem is the thing dropped the nodecount >>>>>by almost 40% . Initial position nodecount was 800000 and now it is 500000. >>>>>Do incremental move attack tables help? And how do i update the table? It seems >>>>>very difficult to update a sliding move and other special cases. >>>>> >>>>>thanks >>>>>daniel >>>> >>>>I have some code for incremental attack tables if you want it. However, it took >>>>Tord 4 months to figure out :) I don't use attack tables in Zappa; i wrote this >>>>when i was considering switching to a piecelist based engine. >>> >>>Is your code 0x88 or bitboard based? >> >>board[64]. Its based on Vincent's move generator. >> >>anthony > >Hi Anthony, > > I had done an incremental attacktable but was not quiet sucessful with it - it >was almost same speed as the previous one : and so removed - potential for more >bugs (kiss). I am very surprised to read it because my attack table was extremely slow and this is the reason that I worked months on updating them incrementally. Calculating the directions that every square is attacked by white and black from scratch is very expensive. It means doing a loop on all squares of the board after every move and for every square doing a loop on all directions to see the direction that it is attacked and the square of the attacker from every direction. Uri
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