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Subject: Re: to the author of SEE engine

Author: Tord Romstad

Date: 08:01:56 10/16/03

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On October 16, 2003 at 10:29:25, Ross Boyd wrote:

>Hi Tord,
>After adding EGTB support to TRACE her rating improvement was barely measurable.
>I think it was 6 elo after at least 200 games.
>And she is definitely an engine that lacks endgame knowledge. :-)

I added tablebase support in Gothmog last week, but haven't tested the
improvement yet.

>Often I see TRACE swindle a draw in R+PvR endgames and sometimes she swindles a
>RvB endgame for a win.

In games against Phalanx (my favorite sparring partner), Gothmog often
gives away a half point in advantageous rook endings by allowing Phalanx
to simplify to a Philidor-type position.  Phalanx apparently knows that
these positions are drawn, but Gothmog still thinks it has good winning
chances.  I think this happens often enough that adding tablebase support
should give a small, but measurable improvement.

Of course, it would be much better to actually implement knowledge about
the third-rank defence in my evaluation function.  I will probably do
so some time in the future.

>But accessing the egtbs is very slow so frequently she loses because her
>NPS is severely hampered..

Huh?  I haven't noticed any slowdown at all.  When do you probe?  I probe
in all positions where the last move was a capture, and the remaining depth
is at least 5 plies.

Perhaps I simply have a much faster hard disk than you, or perhaps my NPS
is so slow to begin with that the disk access doesn't matter much.

>Uri is right when he says the game is usually over before the egtbs can come to
>the rescue.

Usually, but not always.

>So, the main benefit for TRACE has been knowing well in advance that she will be
>checkmated in 47 moves with best play... :-)

Yes, that is the most noticable "improvement", here too.  :-)

Tord




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