Author: Omid David Tabibi
Date: 09:41:48 07/21/03
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On July 21, 2003 at 11:15:30, Vincent Diepeveen wrote: >On July 20, 2003 at 04:55:17, Ryan B. wrote: > >>Questions about verified null move >> >>1. Should the verify be stored in the hash table? At this time I store the >>verify in hash but think I am doing something wrong. My program is playing >>stronger with standard null move set to R=3 than verified null move with R = 3. >>Possibly the verify should not be sorted? > >This is a correct conclusion. > >Verified nullmove is not improving your program except if you test it at mating >positions where checks matter a lot so it gives you another ply then to find >tricks 1 ply sooner. > >However it will play worse. Also it basically shows how bad a qsearch is when in >such positions you do not find the mate in qsearch. > >Also note that overhead of verified nullmove is pretty big. > >The way in which Omid compared in his article is scientific not correct. > You can say whatever you want, but there isn't a week in which I don't receive an email from another programmer who reports that verified R=3 works better than adaptive R=2~3 and standard R=2 or R=3. But of course you have never tried it, so you could never know. And for your information, I know of at least one commercial program which is using verified null-move pruning. >>2. Is it normal to get more cuts in a search than reductions? From The starting >>position I get 18636 reductions and 53901 cuts in 494148 nodes searched (360543 >>of them Qnodes). To me this does not look like it can be right. >> >>Thanks >>-Ryan
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