Author: Tord Romstad
Date: 05:27:54 03/22/04
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On March 22, 2004 at 07:49:17, Daniel Shawul wrote: >On March 22, 2004 at 07:06:53, Tord Romstad 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. >> >>Hello Daniel, >> >>Yes, attack tables tend to be expensive. I calculate them from scratch at >>every node, and my impression is that most others (including Ed) does the >>same. Perhaps it would be possible to do it faster by some sort of >>incremental updating, but I am fairly sure it would still slow you down a lot. >> >>You simply have to decide whether it is worth the cost. >> >>Tord > >Hi Tord > >I am going to use them whatever the cost. But I am intending to do it only at >quiescence nodes [not at internal nodes]. If I use an incremental one I can >also use it for internal nodes too.I am not sure how much i save by doing this >but like you said a minumum of 20% decrease seems inevitable. >I guess you are using the table at internal nodes for move ordering. Not only that. I do a full eval at all internal nodes. The evaluation results for internal nodes are used to shape the search tree. >My see is a very costy operation. But with this attack table i hope it is for >granted? At least I use them for SEE. Originally I used a lookup table (like Rebel), but now I have switched to computing SEE values from the contents of the attack table, and caching the results in a tiny hash table. It is just as fast as the lookup table, and consumes much less memory. >Good luck with Gothmog. [ofcourse it doesn't need my luck,it's already a world >beater!!] Your wishes are most welcome. It is only a world beater in games where it has lots of luck on its side. :-) Good luck to you and DanChess, too! Tord
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