Author: Tony Werten
Date: 23:59:34 11/21/02
Go up one level in this thread
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 ? BTW assuming my program has searchinstabilities instead of realising that you used a woodcounter that may be too simple to reflect the impact on the architecture of a real chessprogram isn't a nice thing to do. > >Tony > >> >> >>>Tony >>> >>>> >>>> >>>>>Tony >>>>> >>>>>> >>>>>> >>>>>>>Uri
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