Author: Peter Fendrich
Date: 05:55:27 03/22/04
Go up one level in this thread
On March 22, 2004 at 08:27:54, Tord Romstad wrote: >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. :-) Right! Good engines seems to have better luck than the others. Strange isn't it? ;-) /Peter
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