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Subject: funny search results, nullmove

Author: macaroni

Date: 15:32:08 12/02/03


this is the analasys from the re-write of my engine from the first position in
WAC.
[D]2rr3k/pp3pp1/1nnqbN1p/3pN3/2pP4/2P3Q1/PPB4P/R4RK1 w - - 0 1
-->"WAC001", best=Qg6
stage=middlegame, playing as WHITE, nullmove is ON, Using
ply=1, value=-200, nodes=113, kNps=0, best=Ne5xc6
ply=2, value=-200, nodes=2546, kNps=11, best=Ne5xc6
ply=3, value=-200, nodes=7708, kNps=18, best=Ne5xc6
ply=4, value=10000, nodes=129225, kNps=88, best=Qg3-g6
ply=5, value=100, nodes=224379, kNps=105, best=Nf6-e8
ply=6, value=10000, nodes=658686, kNps=125, best=Qg3-g6
ply=6, value=10000, nodes=1012767, kNps=129, best=Qg3-g6

it's a very easy mate in 2, and the computer, as expected, finds it at ply 4,
but then disregards it at ply 5, for Ne8, which also just about wins. It is
nullmoving that has caused this, is there any way I can avoid this sort of
problem? it arises, because after playing Qg6, it nullmoves, and calls a 1 ply,
or 0 ply search, in both of these searches, black is better by 200 points, it
doesn't fail in the ply 4 search because there is nothing better, it DOES fail
in the ply 5 search because Ne8 is also good, so beta is 100, not -200.
cheers
tor



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