Author: Mike Byrne
Date: 04:17:56 04/19/04
Go up one level in this thread
On April 18, 2004 at 22:36:34, Mike Byrne wrote: >On April 18, 2004 at 20:36:56, Steve Maughan wrote: > >>I'm looking to implement the new ELO rating support in UCI 2. In the past I >>haven't given much thought as to how one could make an engine predictably >>weaker. Does anyone have any suggestions? After the little thought I have >>given the subject here's what I've come up with. >> >>1. Search to a shallower depth / shorter time. This seems somewhat >>unsatisfactory as it will ignore the other setting. >> >>2. Add random elements to the evaluation term - the bigger the term the weaker >>the play. >> >>3. Round off at the root. So to weaken the engine slightly you would have the >>root round off to 0.1 pawns, a further weakening would be in units of 0.5 pawns >>etc. This means that if a value came back as +1.23 the engine would regard it >>as +1.20. I like this idea since it is relatively simple to implement :-). >>However I'm not sure how effective it would be at actually weakening the engine >>(it may speed the engine up since there may be more cuttoffs!?!). >> >>4. Within the tree you could ignore some moves e.g. all losing capture after x >>depth. This is also interesting. It may closely match how humans think and >>err. Of course it is more complex to implement. >> >>Any other ideas. This could be an interesting area for discussion as it has >>virtually no commercial value (IMO nobody is going to buy an engine that is >>weak). I'd be interested to know of other idea. >> >>Regards, >> >>Steve Maughan > >The two simplest methods are to reduce depth and to provide offbeat score values >for pieces. I use a combination of both in dumming down Crafty in the modified >Se version. In additon, I implemeneted a delay move feature so it would would >not move so quickly while serching to a SD of 3. There are versions that have >tens of thousands of games played already with a rating near 1300/1400 for some >of the weaker personalities. Those operatotors can tell you more than me how >effective the dumb down Crafty's are. The fact that it has already played in >excess of 10,000 games on ICC tells you much people like it. > >With a search depth of 1 with full extensions, Crafty will play near 1500 in >blitz on ICC. To get it weaker, you have to reduce extensions and/or provide >offbeat piece values and/or weaken the evaluation function. I do the first two, >never touched the evaluation function to weaken it. I forgot, the other method I usd is an option called "intensity". Intensity is a value between 1 and 10,000 set by the user- - the engine will take the intensity value , divide by 10,000 and mulitply that by the internally generated time to calculate its move and spend the rest of its time in a simple loop. 10,000 was used, because it was determined that a user would have to use a value between 20 and 50 to make it weak enough for a weak player on today's hardware and could slowly increment it the usage overtime to make Crafty play stronger.
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