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Subject: Re: Handicapping Chess Engines

Author: Robert Hyatt

Date: 12:43:00 10/26/01

Go up one level in this thread


On October 25, 2001 at 14:12:37, Uri Blass 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.
>
>I think that one of the problem is that the games of ICC are usually blitz and I
>guess that the poster talks about 2 hours/40 moves and not about blitz.
>
>I agree that the style is not similiar to humans because humans do tactical
>mistakes that 4 plies is not going to do even at 2 hours/40 moves.
>
>
>>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.
>
>The poster is 1550 player and not 1200 player.
>
>Uri


I wasn't really speaking about _his_ rating.  Just a "low" rating.  IE I
suspect that Crafty at 2 plies would be non-trivial to beat for very weak
players.  I've seen it play (and beat) 2000 players with a rook missing,
on a P6/200...

I think it is hard to get the rating _very_ low.  It isn't hard to weaken
it quite a bit, with a couple of simple commands.  But to do it both
accurately, _and_ allow very low ratings seems pretty hard...



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