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Subject: Re: Singular extensions

Author: Stuart Cracraft

Date: 17:41:54 01/09/98

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Win-at-Chess 141? About 3 1/2 minutes at 29k nodes per second.
Total nodes was a little over 9 million. There were about 400,000
check extensions and 120,000 recapture extensions. Took a partial
7 ply search to see the move and a partial 8 ply search to see
the mate.

On January 08, 1998 at 20:00:31, Robert Hyatt wrote:

>On January 08, 1998 at 17:01:56, Bruce Moreland wrote:
>
>>Could this be how Genius gets the answer to Wac 141 extremely quickly?
>>
>>bruce
>
>
>could be.  I haven't talked with richard in a *long* time.  I do
>remember
>his letting slip that the only difference between two versions of Genius
>was singular extensions, although I can't believe he was able to do both
>the fail-high *and* PV extensions without taking too big a hit.  I seem
>to remember that genius 2 was the program that started with these
>things,
>but I'm no longer certain.  It would certainly help with WAC 141.
>
>BTW, on this subject, after fixing the check extension problem with the
>hash table, I now get a fail high on Qxf4 in 25 seconds or so.  But I
>have
>let Crafty search for a *long* time and it can't get a score back.  Long
>= > 10 minutes.  It gets into the 9 ply search and fails high on Qf4,
>and
>when I have peeked into the tree, it has found a mate, but it apparently
>also follows *lots* of other mating lines as well.
>
>Does anyone else get a real mate here in reasonable time?  I've been
>checking
>extensions and none seem to be "out of control"..  However, this has
>been *the*
>hard problem for Crafty for a couple of years, so at least it now finds
>the
>right move fairly quickly...



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