Author: Robert Hyatt
Date: 13:18:24 09/03/02
Go up one level in this thread
On September 03, 2002 at 15:12:10, Bo Persson wrote: >On September 03, 2002 at 12:03:24, Dave Gomboc wrote: > >>On September 03, 2002 at 11:49:42, Robert Hyatt wrote: >> >>>On September 03, 2002 at 11:30:35, Gian-Carlo Pascutto wrote: >>> >>> >>>I worked on trying it for about three months. I didn't go "all the way" and >>>add both upper/lower scores/moves into the hash table entries, as mtd(f) really >>>needs. But I had to do so many re-searches that I didn't deem it worthwhile to >>>worry with that... I did spend a lot of time trying to limit the number of >>>re-searches. But if you do three or more, you begin to lose to straight PVS >>>in the general case... >>> >>>and you are going to be forced to do at least two searches in the best case... >> >>Well, I do think you need to at least make that switch (to storing both upper >>and lower bounds) to give it a fair shot. If you don't, the algorithm can >>ping-pong like crazy with the "right" input :-) >> >>Dave > >Yes, you might want to try adding two bounds anyway. I started by modifying the >hash table, and then accidentally forgot to include the MTD(f) code, but got a >pretty good improvement anyway. Having two bounds helps reduing the alpha-beta >windows from both sides. > >On the other hand, I have tried MTD(f) for a lot longer than 3 months, and still >have this "fast, fast, fast, hit-the-wall" effect, where 10 plies takes less >than a second and ply 11 takes forever. > > > >Bo Persson >bop2@telia.com That was the effect I had. Several searches would go a bit faster than with PVS, but then "blam", when the score changed a lot. And it would start "hunting"...
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.