Author: Mridul Muralidharan
Date: 06:44:42 03/23/04
Go up one level in this thread
On March 23, 2004 at 04:42:31, Uri Blass wrote: >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 As I had already opsted in this forum , my attacktable generator is based on Vincent's move generator - and there are other optimisations possible with it that has not been presented in his post. And , I am not a bitboarder - and follow a board structure which is quiet similar to GNUChess 4. This makes it not that expensive - but still quiet expensive :( Mridul
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