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Subject: Re: some results of Deep Fritz on the nolot test suite

Author: Ed Schröder

Date: 08:00:37 09/01/01

Go up one level in this thread


On September 01, 2001 at 09:55:25, Robert Hyatt wrote:

>On September 01, 2001 at 08:48:00, Vincent Diepeveen wrote:
>
>>
>>You are entirely right Ed, i have singular extensions inside diep now
>>and play with them turned on tournaments now. first tournament i played
>>with them turned on was back in 1994 the dutch open championship,
>>but my implementation sucked bigtime there. Then in paderborn 2001 i
>>used a better implementation with big reduction factor (R=3) and
>>also in combination with other extensions. The reason i have them
>>inside diep now is
>>  a) diep doesn't search very deeply so overhead isn't too big then
>>  b) to solve testpositions quicker otherwise i need days to solve things
>>
>>However what i notice is that in mainlines in complex positions the
>>value of singular extensions is very limited. Of course if i'm already
>>won i see mates way before my opponent sees them (in middlegame) or
>>i see a win way before my opponent sees it, as well as that Rxf7 move
>>which ferret played against gandalf i see within seconds with within 90
>>seconds the right score, but after all the only impact of singular extensions
>>is that they give a psychological good feeling "i'm not going to lose
>>because of a cheap trick if my program messes up". Of course combinations
>>can only be there and getting outsearched is only important if a program
>>plays completely anti positional chess.
>>
>>In normal game play and in sound positions, there the value of SE and similar
>>extensions gets hugely overrated i think.
>
>
>I don't believe they _hurt_ when done right.  The _last_ report by the DB
>team suggested that SE was worth maybe 10-20 Elo rating points at most.  Their
>first report suggested far greater improvement, but this was because it did far
>better on test suites.  In matches, it won, but the margin of victory was much
>less than the test suite results suggested...
>
>My tests in CB produced the same results.  Modest improvements in games, some-
>times wild improvements in test positions.  But even though the improvement in
>games is very modest, that one game here or there is _still_ very important.
>That could be your game vs Kramnik in a big tournament, for example.


Then why is SE not in Crafty when SE is an improvement?

Ed



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