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Subject: Re: programmer's position

Author: Dieter Buerssner

Date: 11:37:18 04/16/03

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On April 15, 2003 at 17:23:09, Will Singleton wrote:

>r1br2k1/p1q2ppp/2n2n2/2B5/P1BNp3/1QP1P3/5PPP/R4RK1 b - -
>
>Some programs never show an elevated score, others show +2 or so before figuring
>it out.  It has to do with a piece that is guarding a pinned piece at the end of
>the pv.  Ruffian and Yace 99.5 exhibit the problem, while Tao doesn't.  I'm
>wondering if this problem is due to a lack of extensions in the pv, or a qsearch
>artifact, or something else.
>10 216 736 3122242 Ne5 Qb4 Nxc4 Nb5 Qc6 Qxc4 Rd5 Rd1 Rxc5 Rd8 Ne8
>
>However, at the end of that pv, you get the following position:

This PV is 11 ply deep, probably no extensions (?). I just tried Yace, and it
neede 11 ply, to get a drawish score. Disabling all pruning in qsearch (and
using even some very limited extensions in qsearch) did not make a difference.
But it is probably a bit more complicated as that. I also should check
carefully, if really all pruning in qsearch was disabled. At least the line QxR
QxQ RxN+ Qf8 RxQ KxR should be seen in qsearch here.

Can you show some analysis of programs, that never show a higher score of black?

Regards,
Dieter



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