Author: Gerd Isenberg
Date: 11:55:16 12/28/02
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On December 28, 2002 at 14:00:05, Vincent Diepeveen wrote: >On December 28, 2002 at 12:31:01, Alessandro Damiani wrote: > >>On December 28, 2002 at 12:15:46, Vincent Diepeveen wrote: >> >>>On December 28, 2002 at 11:18:58, Alessandro Damiani wrote: >>> >>>>On December 28, 2002 at 10:10:53, Ricardo Gibert wrote: >>>> >>>>>It seems Ed Schröder has added a bit more to his web page: >>>>> >>>>>http://members.home.nl/matador/chess840.htm#SEARCH >>>>> >>>>>I have the feeling that ES will be getting a lot of thank yous for quite awhile >>>>>for his fine contributions to computer chess. >>>>> >>>>>Thanks again! >>>> >>>>It seems to me that there are two typos in the following code: >>> >>>it's not about the source code. It's about the idea. >>>Any sort of pseudo code gets accepted then. Definitely >>>by me. >> >>I am talking about the pseudo code Ed published on his homepage (pseudo code is >>still code). I don't understand your statement in this context. >> >> >>> >>>Of course do not forget that these reductions are very dangerous >>>to use in combination with nullmove and that as Ed describes them >>>they completely rape your hashtable. A depth stored as 'n depth left' >>>might be in reality n+1. You need to add a bit and some code for >>>transpositions to the hashtable in order to fix that. >>> >> >>My new variant of ABC uses depth reductions instead of extensions. So I am >>looking at the difference between Ed's reductions and mine. I don't use >>conventional null-move yet. >> >>There is a doctoral thesis by Thomas Barth which describes how depth reductions >>work fine with a hashtable. His work is from 1988. >> >>Alessandro > >I do not know the work of Barth here, but i know that without >modifying the hashtable you run into trouble a lot. > >In the 90s several publications from Feldmann ignored the hashtable >problem with his Fail High reductions. > >Note that though the implementation detail of Ed seems small compared >to the FHR concept of Feldmann, the implementation of Ed is practically >working a lot better. FHR is based on nullmove observation. Rather than doing a nullmove-cutoff they reduced the depth. Isn't Ed's approach more like Heinz's "limited razor"? Gerd > >It's conceptual the same thing of course. I can't remember so quickly >whether Feldmann did them also non recursively.
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