Author: Bruce Moreland
Date: 00:04:03 11/28/00
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On November 27, 2000 at 19:36:18, Scott Gasch wrote: >Hi, > >I recently attempted to change my move ordering so that "losing" captures >(MVV/LVA) were searched after everything else. This resulted in search trees >about 30% larger than when I searched all captures at once, best to worst >(MVV/LVA) before any non-capture moves. Perhaps Ernst figured out a way to do this better, but I don't think that MVV/LVA can detect losing captures. QxR is either great or terrible, but MVV/LVA can't tell you which. If it is great, it should be sorted first. What I'm hearing from you is that it's mostly great. It sounds like you have discovered that most downward captures in a search tree are captures of an undefended piece. bruce > >The reason I tried this was because both Prof. Hyatt and an article online by E. >Heinz suggest losing captures should be tried last for better move ordering. >Does this rule hold if I am doing a simple MVV/LVA move value scheme instead of >a more complicated SEE? How can I be sure a capture is "losing" just because >the piece I capture with is more valueable than the captured piece? > >Should qxn when n is hung be search last in a position just because it's >considered "losing" since the queen > knight? This seems wrong to me because >most likely such a hung-knight position would be a beta cutoff and we could have >saved all the work of considering all other non-capture moves in this position >had we looked at this "losing" capture first. IS this just the exception to the >rule? Don't get me wrong, I'm all for apparently "better" captures before >"worse" ones but I wonder if I am misunderstanding where to search the "worse" >capture moves. It would seem to be so since my tree expands after I make this >change. > >Scott
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