Author: Uri Blass
Date: 07:47:00 11/22/02
Go up one level in this thread
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. Uri
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