Author: Uri Blass
Date: 12:18:42 11/21/02
Go up one level in this thread
On November 21, 2002 at 13:52:33, Omid David Tabibi wrote: >On November 21, 2002 at 13:05:28, Uri Blass wrote: > >>On November 21, 2002 at 09:16:09, Omid David Tabibi wrote: >> >>>On November 21, 2002 at 08:34:36, Uri Blass wrote: >>> >>>>1)I do not find in the pseudo code in figure 3 undo null move. >>>> >>>>I assume that it should be before if value>=beta and after value=-search(...) >>>>Am I right? >>>> >>> >>>That is why it is called *pseudo*-code :-) >>>You have to fill in the obvious parts by yourself... >>> >>> >>>>2)What is the value of the research for tactical strength? >>>>Should it help significantly relative to searching to reduced depth when >>>>value>=beta without research (even when we get value that is less than beta). >>>> >>> >>>I didn't understand the question. Dp you mean doing a shallow search even when >>>we don't have a fail-high report?! >> >>I meant to ask what is the tactical value of the research(You suggested people >>to start with doing it without the research first and only after it works to do >>it with the research) >> > >The re-search is needed only in zugzwang positions. Such zugzwang positions >occur very rarely in midgames; so you can forgo the zugzwang detection re-search >and still benefit all the improved tactical performance. Maybe there is something that I do not understand but it seems to me that the research may be theoretically important also in middle game positions(no zugzwang positions). Without the research I do 2 searches and with the research I do 3 searches. It is possible that I see lower scores when I search deeper(because of the horizon effect). In this case the following can happen: 1)I get beta in search A(When I assume the opponent plays null move but search to small depth because of R=3) 2)I get alpha+beta/2 in search B(search to verify the null move that has bigger depth) 3)I get alpha after the research(searching to even deeper depth) It means that without the research I get different score than the score with the research and a different score may lead to a different result. Uri
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