Author: Christophe Theron
Date: 11:12:31 11/10/00
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On November 10, 2000 at 09:16:06, Mogens Larsen wrote:
>On November 10, 2000 at 08:41:24, Uri Blass wrote:
>
>>The question is how do you combine the 2 programs.
>
>Exactly. That was the point of my last paragraph. I suppose it would be
>essential to analyze where the strengths and weaknesses of the programs differ
>and interpret them as patterns recognizeable for some sort of evaluation
>function.
>
>I was talking with Bob about applying SMP knowledge to run different engines at
>the same time and base the selectivity on an advanced evaluation engine. I still
>think it's possible to implement and get good results.
>
>>I thought about the idea of a root processor that decides based on the root
>>position which engine to use.
>
>What should a root processor "look" for?
>
>>It can be based on previous evaluations of the program.
>>
>>I think that starting to use tiger13 when Gambittiger shows big scores may be a
>>good idea because when gambit shows a big score the job of attacking was done
>>and the problem of tiger that I found in the game against crafty that was posted
>>by thorsten was that it did not like to go to an endgame and prefered
>>speculation of 3 pawns and not winning a rook for a bishop but I do not believe
>>that it can lead to an improvement of more than 20-30 elo.
>
>It might be useful to make certain that the high evaluation of GT is maintained
>for x number of moves before concluding that the attack has accomplished a
>winning position by transposing to the endgame. Basically that would mean
>reducing or removing "speculation" altogether at a cetain point in the endgame.
>
>Maybe it's possible to encourage or favour the speculative approach in certain
>positions where the structure is immoveable in order to open up for the tactics.
>That might not necessarily be a good idea.
>
>Mogens.
This discussion between you and Uri sounds interesting, and the ideas might be
true and useable.
However I see a much simpler way to get an already significant improvement by
using Chess Tiger 13.0 and Gambit Tiger 1.0 together, and any owner of the Rebel
11 CD can do it:
The trick is very simple: just decide to use either Chess Tiger or Gambit Tiger
depending on which opponent you have to play.
During the beta test period, we have gathered informations about the performance
of the two engines, and we have noticed that against some opponents Gambit Tiger
was scoring very well, while against other opponents Chess Tiger did much
better.
I should dig into my archives to find the right information, but I remember that
for example Gambit Tiger 1.0 crushed Shredder 4, and did 50% against Junior6.
Chess Tiger 13.0 did much better against Junior6. This has been reported by
several testers, who have played matches independantly.
These two opponents are just an example. The important point is that Chess Tiger
and Gambit Tiger have different winning profile against different opponents and
it must be possible to take advantage of this.
Given that against a given opponent the difference in winning percentage between
Chess Tiger and Gambit Tiger can easily be around 10%, I guess that the
difference between "using always the same Tiger engine" and "using the right
Tiger engine for an opponent" could be 5% in average, which makes an elo
difference of 35 elo points.
Given the current level of competition between chess progams, 35 elo points is a
significant advantage.
If the idea of selecting the engine depending on the opponent sounds shocking to
you, remember that this strategy is a main source of success for human players.
Human players KNOW who they are playing, and adapt their style according to
their opponent (and also according to the specific conditions of the game).
The players able to adapt gain a lot of points because of this, and this
strategy is considered with respect amongst human players.
I think that using Sarah's tournaments results (which are public) it must be
possible to see against which opponents Gambit Tiger performs better. It should
also be possible from these public results to see if by selectively using Gambit
Tiger or Chess Tiger it is possible to get a much better performance for the
"Tiger family".
Then an experiment could be done in order to verify that the improvement is
consistent and reproductible.
I believe an elo improvement of 35 points is possible.
Christophe
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