Author: Vincent Diepeveen
Date: 11:08:05 12/28/02
Go up one level in this thread
On December 28, 2002 at 14:05:56, Tony Werten wrote: >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. >> >>It's conceptual the same thing of course. I can't remember so quickly >>whether Feldmann did them also non recursively. > >No, he allowed them recursive. That's why it sucked. >That is time to solution, because you need more ply. Nodes to depth, it looked >great. (Just like randomly skipping moves ) the problem of most 'reductions' is the hard fact that you lose a full ply near the root. Random skipping moves compared to that is not such a bad idea :) >Tony
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