Author: Vincent Diepeveen
Date: 05:21:26 08/08/00
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On August 07, 2000 at 20:04:18, Dave Gomboc wrote: >On August 06, 2000 at 20:26:06, Vincent Diepeveen wrote: > >>Actually MTD is great for testsets. MTD is having a huge problem if >>you start playing games with it however and the vice versa happens. > >Completely unjustified, as always. > >>If i'm at 0.600 now with PVS at iteration is 8, and the chess prog >>starts smelling trouble, then suppose we fail low to 0.300, now >>aren't that 300 researches with MTD? >> >> THREEHUNDERD RESEARCHES? > >Vincent, if it takes you 300 researches to fail low by 0.3 pawns with mtd(), >your code is seriously broken. > >Dave Using MTD it's easy to research using only 1 point: bound,bound+1 if bound a bit lower then newbound = bound-1; then search at newbound,newbound+1 Now that's something you can do quick. As soon as you go jump in scores in a binary way newbound = bound-2; then search at bound-3,bound-2 no if fails again low then bound-5,bound-4 Then you lose a big advantage of MTD, namely that you search the same space with about the same score. Now you suddenly need to see entire new trees, and that all because you don't use but prefer to get a lot of overhead to get there. Better works: -infinite So any number of researches is a bigger overhead as using PVS, and that in positions which are CRUCIAL to your game!
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