Author: Robert Hyatt
Date: 10:16:08 12/18/02
Go up one level in this thread
On December 17, 2002 at 19:16:26, Vincent Diepeveen wrote: >On December 17, 2002 at 18:21:28, Uri Blass wrote: > >>On December 17, 2002 at 18:11:20, Vincent Diepeveen wrote: >> >>>On December 17, 2002 at 17:30:36, Bruce Moreland wrote: >>> >>>if you go back in time a bit you see that i had >>>major problems with Omids article and posted it here. >>> >>>there is more than just the problems you see there. >>> >>>also look at his homepage and get the positions he tested >>>and then look to his node counts. for a mate in 2 position >>>where i need like a couple of hundreds of nodes to get to 10 ply >>>he needs 10 million nodes. then R=3 reduces that more. >>> >>>also his implementation is buggy of course. it doesn't take into >>>account problems with transpositions. a classical beginners problem. >>> >>>But most important is that verification search is not something new >>>it is a buggy implementation of something already described years ago >>>with only 'novelty' that omid turns off nullmove *completely* >>>after he finds a nullmove failure. >> >>No he does not. >>There is no point in the tree that he turns off nullmove completely. >> >>> >>>All with all a very sad article. The only good thing about it is >>>the quantity of tests done. >>> >>>The test methods and the implementation and the conclusions are >>>grammar school level. >>> >>>I do not know who proofread it, but it gotta be idiots or people who >>>didn't care at all. >>> >>>Amazingly Bob defended Omid here and said nothing was wrong with >>>the article. >> >>Bob also found that verification search is good for crafty based on his post. >>Bob is not the onlyone who defended Omid. >> >>I also defend him and you are the only poster who attacks him(even posters who >>said that it did not work for them did not say that it is very bad). >>Most of what you say is not correct. >> >>Uri > >You are dreaming. > >Ok to list a few bugs in his paper: > > a) all his test positions are mates and he doesn't do > checks in qsearch so R=2 versus R=3 matters a lot because > of the extra ply you miss of the main search finding the > mate for you. So if your qsearch is so buggy it is logical > that R=2 works at depth==9 better than R=3 at depth==9, > this is *trivial*. It is so trivial that no serious researcher > should compare the same plydepths with each other without > taking into account time. > > Because we are going to conclude that minimax search is better > than alfabeta for sure. That is simply nonsense. That is a conclusion I could see _you_ making. But not anybody else. > > b) now already assuming the bug in his comparision is there to > compare depth==9 with depth==9 instead of the factor time, > then the bug is that he is just testing mates so reduction > factor matters. It is trivial to try adaptive nullmove then. > > c) there is major bugs in the program Genesis looking at the > branching factor differences between R=1, R=2 and R=3. > I do not know a single serious chess program that has > such a difference. > > d) Genesis needs way too much nodes to get to a decent plydepth > when compared to even programs doing checks in their qsearch > and extensions in nominal search. For mate in 2 he needs like > 10 million nodes to get to depth == 10. So? If you force the search to a specific depth, that is not an unexpected thing. > > e) illegal position in his testset. > > f) his algorithm is not new. It is a rewrite of something already > existing and he rewrote it wrong. He has a bug in his verification > search. You can easily proof it by using transpositions. It is "new". It is similar (in ways) to an old idea but it is also new in ways. > > g) It won't detect a zugzwang for sure simply because of transposition > bugs. Therefore the only claim can be that it is enhancing tactical > abilities of his program. Therefore it is crucial to also test > different forms of adaptive nullmove (with different depths to > go from R=3 to R=2). > > h) It is unclear why he concluded verification search is better using > his own data. > a) more Fullwidth search than verification > clearly finds more positions. > > b) R=3 uses less nodes than his verification search. > > it is very unclear how he concludes then that verification search > is better. It's topping nowhere a list of 'this works better'. > > i) Even from where i sit and without having genesis i can already smell > that adaptive nullmove works better than his own verification search. > his beloved verification search you can easily write down what it is > doing on paper. It's simply avoiding to nullmove last few plies > initially. So there is always a form of adaptive nullmove that is > going to completely outgun it simply. > > j) the testset is just basically mating positions in all tests. > that's a very dangerous ground to conclude things. > >Note that at depth == 10 ply i solve with diep with R=3 i solve far more >positions in way less nodes than this guy ever will. This testset is just >too simple. So???
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