Author: Peter McKenzie
Date: 20:06:12 02/16/99
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On February 16, 1999 at 22:34:32, Robert Hyatt wrote: >On February 16, 1999 at 16:26:53, James Robertson wrote: > >>My program keeps falling prey to king attacks. Although it does very well >>tactically when it's king is not threatened, it frequently plays combinations >>that win material (it thinks), only to find, say, a back-rank mate that went >>unnoticed. I am using a one-reply-to-check extension, the mate extension after >>null move, and extending half a ply whenever there is a check in the tree. No I haven't tried the mate extension after null move yet, do you think it is very effective? >>check detection is done in the q-search. Are there any other standard check >>extensions I am not doing? I've heard that some programs extend on captures by (or adjacent to maybe) the King, but I've never tried this. >> >>James > >Half a ply for check is very conservative. I use 1 ply for all checks, 3/4 >ply for one-legal-reply-to-check... Yes, I extend a full ply for check - I think this is pretty standard. I don't do partial ply, so I limit the number of one-legal-reply-to-check extensions to something like 3 in any given branch of the search tree. > >but speed is the main thing you need. Or else resorting to selective approaches q-srch is of course a selective search, I think it is a common idea to try checks in the q-srch. Either only in the first N ply of q-srch or only 'good looking' checks. The other thing to try is playing all responses to check in the q-srch, even if they aren't captures. These changes to your q-srch will of course cost you nodes, it is debatable whether they are worthwhile. >to get the depth you need. Or else tuning your evaluation to protect your king >better. The chess servers will _really_ help you do this, of course... Sure does! Peter
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