Author: Robert Hyatt
Date: 20:57:00 09/02/02
Go up one level in this thread
On September 02, 2002 at 19:54:20, Vincent Diepeveen wrote: >On September 02, 2002 at 02:19:08, Ricardo Gibert wrote: > >without hashtable you can put mtd in the toilet. Not if 99.99999% of the time you only need one search... > >>On September 01, 2002 at 13:41:19, Gian-Carlo Pascutto wrote: >> >>>On September 01, 2002 at 13:28:20, Robert Hyatt wrote: >>> >>>>On September 01, 2002 at 03:20:20, Gian-Carlo Pascutto wrote: >>>> >>>>>On August 31, 2002 at 23:54:31, Robert Hyatt wrote: >>>>> >>>>>>Interesting question. Deep Blue essentially used it in the chess hardware, >>>>>>which means the last software ply was a sort of mtd(f) search. >>>>> >>>>>Except that it was missing the 'm' in mtd(f), which made it horribly >>>>>inefficient. >>>>> >>>>>-- >>>>>GCP >>>> >>>> >>>>I don't agree. They simply had a piece of hardware that could search a >>>>null-window tree, and nothing else. Which is all a single search in a single >>>>iteration of mtd(f) can do. The software provided the "m" at the point where >>>>the software handed things off to the hardware... >>> >>>Nonsense. The point of MTD is to use a hashtable to prevent wasted work when >>>researching the tree and trying to converge on a value. The Deep Blue chess >>>chips did *not* have hashtables. This makes them horribly inefficient, as anyone >>>that has actually used or uses MTD will tell you. >> >>This isn't clear. Remember the hardware is not searching near the root. It is >>only searching near the leaves. The vast majority of the time, all you may want >>to show near the leaves is if all the "relevant" positions in the subtree are >>greater or less than a certain bound. For this mtd(f) would fit the bill just >>fine despite the absence of a hash table as long as a research does not need to >>be performed. Whether or not it is really inefficient depends on how it is used. >>However, you are right that "mtd(f)" is something of a misnomer as the "m" is >>missing as you have noted. >> >>> >>>The fact that the software part of their search had hashtables has *nothing* to >>>do with this. >>> >>>-- >>>GCP
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