Author: Omid David Tabibi
Date: 07:52:03 11/22/02
Go up one level in this thread
On November 22, 2002 at 10:47:00, Uri Blass wrote: >On November 22, 2002 at 03:46:06, Tony Werten wrote: > >>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 > >I now checked with movei and counted 63 horizon effects in the first 10,000,000 >nodes. > By 63 horizon effects you mean zugzwang detection (they are two different things!)? >Uri
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