Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: What do you do in your qsearch?

Author: Ross Boyd

Date: 04:36:44 11/06/03

Go up one level in this thread


On November 06, 2003 at 04:51:38, José Carlos wrote:

>  This position is easy, but interesting:
>
>[D]r2qk2r/pp3ppp/2pbpn2/4Nb2/PnBP2P1/2N1P3/1P3P1P/R1BQ1RK1 b kq g3 0 1
>
>  Black plays Ng4 with big advantage.
>  Anubis (complex qsearch) finds it in iteration 8, while Averno (simple
>qsearch) needs 12. Studying what the program was searching in qsearch in this
>position has been very interesting for me.
>  How does your program here?
>
>  José C.


Hi Jose,

Its an interesting topic.... I have a weak engine with a fairly standard qsearch
ie. simple standpat plus SEE pruning - with check evasions.

I'm investigating beefing up the qsearch to include checking moves and some
static threat extensions, like for example, forks ie. if two black pieces can be
forked by a white pawn then look deeper rather than stand pat.
I don't know how successful this will be but I'm hoping for some tactical
improvement. An alternative and possibly 'cheaper' approach is to evaluate these
potential forks statically... but I haven't tried any of this yet. Hope it
works. :-)

Anyway, here is TRACE's analysis of your position... she finds Ng4 in 10 ply
which is halfway between Anubis and Averno... which may be due to extensions,
but its hard to tell.

Ross

New position
r2qk2r/pp3ppp/2pbpn2/4Nb2/PnBP2P1/2N1P3/1P3P1P/R1BQ1RK1 b kq g3 0 1

Analysis by TRACE 1.25 on PIII-600Mhz 64Mb Hash:

1...Bxe5 2.gxf5
  =  (-0.07)   depth: 2   00:00:00
1...Bxe5 2.gxf5 Bd6 3.fxe6
  ±  (1.39)   depth: 3   00:00:00
  =  (-0.21)   depth: 4   00:00:00
1...Bc2 2.Qe2 0-0 3.Bd2 Nbd5 4.Nxd5 cxd5
  =+ (-0.29)   depth: 5   00:00:00  20kN
1...Bc2 2.Qf3 0-0 3.Bd2 Nd7 4.Nxd7 Qxd7
  =  (-0.24)   depth: 6   00:00:00  32kN
1...Bc2 2.Qf3 0-0 3.e4 Qc7 4.Bf4
  =  (-0.24)   depth: 7   00:00:01  98kN
1...Bc2 2.Qe2 0-0 3.Na2 Nxa2 4.Rxa2 Bb1 5.Ra1
  =+ (-0.34)   depth: 8   00:00:04  557kN
1...Bc2 2.Qf3 0-0 3.b3 Nbd5 4.Bb2 Nb6 5.Qe2 Nxc4 6.Qxc4
  =+ (-0.39)   depth: 9   00:00:08  1769kN
1...Bc2 2.Qe2 0-0 3.Bd2 Bxe5 4.dxe5 Nxg4 5.Qxg4 Qxd2 6.Bxe6
  =+ (-0.33)   depth: 10   00:00:25  4947kN
1...Nxg4
  =+ (-0.34)   depth: 10   00:00:32  6520kN
1...Nxg4 2.Nxg4 Qh4 3.h3 h5 4.Be2 hxg4 5.Bxg4 0-0-0 6.Bd2
  -+ (-0.86)   depth: 10   00:00:42  8945kN
1...Nxg4 2.Nxg4 Qh4 3.h3 h5 4.Be2 hxg4 5.Bxg4 Bd3 6.Re1 0-0-0
  -+ (-1.06)   depth: 11   00:01:10  15564kN
1...Nxg4 2.Nxg4 Qh4 3.h3 h5 4.Ne5 Bxh3
  -+ (-1.19)   depth: 12   00:02:22  33488kN
1...Nxg4
  -+ (-1.44)   depth: 13   00:08:47  121798kN
1...Nxg4 2.Nxg4 Qh4 3.f3 Bxg4 4.Rf2 Bf5 5.e4 Bg6 6.Be3 0-0 7.Rc1 Rad8 8.Rg2
  -+ (-1.36)   depth: 14   00:21:24  310116kN




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.