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Subject: Re: Null move R=3

Author: Bruce Moreland

Date: 23:46:45 08/08/01

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On August 09, 2001 at 00:42:38, Robert Hyatt wrote:

>I should have added that I played this a good while before Ernst reported his
>results in the JICCA.  Stanback started me on this trail about 4 years ago or
>so.  He suggested using R=2 normally, but using R=1 near the tips to avoid
>hiding the tactical problems that R=2 causes near to the tips (it collapses
>me right into the q-search, which is a problem).  That got me to thinking at

This would suck, I bet.

>the time that R=2 to R=1 was not a bad idea, but the R=1 really hurt performance
>as you might guess.  As my search got deeper (going from the P5/133 to the
>P6/200 was quite a jump in speed, roughly 2.5X or so) R=2 became more
>trustworthy and that was when I started toying around with R=2 or R=3, right
>after the match you and I played for fun one night where you used R=3 and we
>didn't see anything bad happen to Ferret as a result.

I used R=4 and didn't see a problem.  I've used very high R and haven't seen a
problem.  Other than not doing as well on tactical tests.

>I believe that Ernst and I slightly disagreed on where to make the switch
>from 3 to 2...  I chose my "shift point" after playing lots of test matches,
>while Ernst used test position results to adjust his.  We ended up within a
>ply of each other if I recall, although I think he might have shifted further
>away from my shit point later on after more testing.
>
>I tried lots of things, including a gradual reduction from 3 to 2, using
>fractional ply reductions...  and I even tried R=4 to 2.  Which didn't look
>bad.  However, I was a bit suspicious of R=3, so R=4 really got my super-
>stition active.  I used to hate R=2 if you recall.  And I am pretty sure
>that R=2 to R=3 is worse at blitz but better at longer time controls.  But
>not _hugely_ better...  just "better".  But I used games to judge this, which
>might not be the best way.
>
>There is still plenty of things to try with this 'adaptive' behavior.  I doubt
>the last word has been written yet...  John Stanback served as the catalyst for
>me.  It is possible that (a) he has experimented with this a lot as well,
>although I didn't hear him mention R=3/2 when he was talking about R=2/1 back
>then.  (b) he heard about the adaptive R adjustment from someone else himself
>and was just relaying what he had heard rather than what he had tried.
>
>No idea whether he was the first to suggest this or not.   In my case, it was
>simply a natural extension of his idea to go from 2/1 to test the 3/2 shift as
>well.
>
>I can certainly run some test suite of your choice with R=2 and R=3/2 to see
>the difference, if you want...

I don't have time to do a lot of analysis of this now, since all of my machines
are busy constantly until the end of the month.

If you don't do it, I will do it later.

bruce

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>>>Frank



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