Author: Tony Werten
Date: 00:46:06 11/22/02
Go up one level in this thread
On November 22, 2002 at 03:31:37, Uri Blass wrote: >On November 22, 2002 at 02:59:34, Tony Werten wrote: > >>On November 22, 2002 at 02:44:52, Tony Werten wrote: >> >>>On November 21, 2002 at 17:01:11, Omid David Tabibi wrote: >>> >>>>On November 21, 2002 at 16:55:04, Tony Werten wrote: >>>> >>>>>On November 21, 2002 at 16:19:17, Omid David Tabibi wrote: >>>>> >>>>>>On November 21, 2002 at 16:05:45, Tony Werten wrote: >>>>>> >>>>>>>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. >>>>>>> >>>>>>>I was quite surprised to see them from the starting position at a rate of 5 per >>>>>>>second. Not impressive, XiniX searches 400 Kn/s there, but still surprising. >>>>>>> >>>>>> >>>>>>The rate of what, was 5 per second? >>>>> >>>>>"Zugzwang positions" or rather, positions where nullmove would have given a >>>>>cutoff but that after reducing depth and searching gave a score < beta. >>>>> >>>> >>>>You mean you got an average of 5 zugzwang indications per second in middle >>>>game?!!! Then your program has instabilities which cause a huge number of >>>>needless re-searches due to false zugzwang alarm. Turn off your zugzwang >>>>detection at once! >>> >>>I'm quite interested in finding out what is happening so I'll leave it in for a >>>while. I think it has something to do with tempo. XiniX doesn't use futility >>>pruning so I'm quite curious to know if programs that do, have a bigger false >>>zugzwang count. >> >>Think I found it. Your algoritm doesn't seem to work correctly with threat >>detection, causing instabilities. Maybe your testprogram didn't use it ? > >I do not understand > >Can you explain? > >I did not find something strange with the 5 "Zugzwang" per second in the opening >position because I assume that it is all about the horizon effect and not about >real zugzwang positions". Yes, and R=3 gets the horizon closer than R=2. Threats fe get found easier with R=2. Tony > >Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.