Author: Robert Hyatt
Date: 12:40:33 10/26/01
Go up one level in this thread
On October 25, 2001 at 16:20:42, John Merlino wrote: >On October 25, 2001 at 12:02:29, Robert Hyatt wrote: > >>On October 25, 2001 at 06:37:00, Mike Hood wrote: >> >>>There have been a lot of posts (over the years) about how to make engines >>>weaker. This is an interesting question that I'd like to revive. I mean, it's >>>not just about getting to the top of the SSDF list. Very few people who buy a >>>current chess program at its full unleashed power stand a chance of even drawing >>>against it. It's a matter of playing enjoyable (and instructive) chess in your >>>spare time. >>> >>>I'm disappointed with most of the handicap levels in chess programs. Everything >>>from "Drunken Assassin" to "Paranoid Scaredycat" delivers poor chess, making >>>stupid blunders that anyone with an ELO rating over 1000 can take advantage of. >>>The only successful handicapping that I've seen is limiting the ply depth of the >>>search. Limiting the ply search of an engine to 4 (or maybe 6) ply leads to the >>>engine playing solid but beatable chess. Maybe I'm just speaking from my own >>>limited perspective as a 1550 player, but I have the impression that the >>>blunders made by a plydepth-limited engine are very "human". >> >>I don't think this works. I ran some tests on one of the chess servers once >>with a very limited search depth and still saw ratings of over 2200 at times. >> >>Bruce ran a version of Ferret on ICC with a time limit of milliseconds per >>move and it too was in the 2200 range if I recall correctly. >> >>The problem is that against weaker players, even shallow searches see through >>their simple tactics, and you _still_ have the full positional evaluation of >>the program, with weak squares, pawn structure, king safety, etc. to guide the >>program. >> >>If you reduce the search depth, you only reduce tactics. You won't find a >>1200 player that understands much about pawn majorities, weak pawns, king >>safety, etc. You end up with a program that is tactically weaker, but still >>positionally very strong. And (IMHO) it just doesn't "feel right". IE weak >>players will let me wreck their pawn structure where a shallow search program >>will not. > >We have found this also to be the case with Chessmaster. There are a few >personalities that are identical to the Chessmaster personality, but have a VERY >limited search depth. Vlad has a search depth of 3, and his rating came out to >approximately 1850. Max has a depth of 2, with a rating of around 1600. And >Lacey (the bane of all existence) has a depth of 1, with a rating of around >1300. So, I would estimate that a search depth of 5 would be approximately in >the 2200 range that you mention above. > >Does that come close to matching your findings? > >jm I haven't tried fixed depth very much. Because it is _way_ too "uneven" overall. IE N plies in the middlegame might play at rating X, while N plies in the endgame plays at rating X-N because in the endgame X plies go by much quicker. If I had a lot of time, I would try to set up a few ICC accounts that played at specific levels. And tune them to do so. However, I think it would be a non-trivial task, particularly to reach lower levels like 1300 - 1600 or so. And then there is the hardware issue that would require some sort of quick benchmark to establish some speed reference point.
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