Author: Filip Tvrzsky
Date: 14:20:46 01/14/04
Go up one level in this thread
On January 14, 2004 at 16:56:20, Anthony Cozzie wrote: >On January 14, 2004 at 16:26:42, Ed Trice wrote: > >> >>> >>>Have you considered trying MTD(f) instead of PVS? I am not sure it is any more >>>efficient in practice, but it is easier to code, and has the additional benefit >>>of making you feel different, original, interesting, intelligent, handsome and >>>attractive. >>> >> >>Well Aske Plaat would love to hear that :) >> >>But doesn't MTD(f) trigger a great deal of researches? I remember trying that >>once and it bloated the tree. > >---- opinion mode on ---- > >MTD(f) has two big problems. > >1, you ponder the wrong move occasionally because your PVs are less accurate. >If you are pondering the wrong move 20% of the time that is equivalent to a 10% >time loss. > >2, MTD(f) is at its worst when the score is dropping. A fail high in MTD(F) is >much faster than a fail low (1 child node vs all child nodes). Unfortunately, >this is when you need your search the most: you are in trouble, and you need to >make exact moves to win/draw (you might already be lost, but thats just the way >it goes). I remember some Zappa-Gothmog games where Gothmog had been searching >8 ply, got in a tight spot, made a 6 ply search, played a huge blunder, and went >from -1 to -5 the next move. > >---- opinion mode off ---- > >Most people that try MTD(f) will give up very fast because it requires a >two-limit hash table rather than a bound hash like most people implement. I have noticed this in several postings before but still do not follow: why is with MTD(f) necessary to store two limits in hash table instead of only one? Filip >Its a >difference of style, but in my opinion worst case performance is key when for >search. There is some interesting room for work IMHO with MTD(f)/PVS hybrids. > >anthony
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