For Marco---possible Stockfish bug

[lech]

Hi Marek,

what you are doing seems to me like an artificial contempt factor.
Of course, it will sometimes help.

Maybe, but I always try to help, if I feel that I can.
Do you like to read or hear: "stupied engines"?

[lech]

I found a next very interesting example with a logical solution.
[d]8/5p2/8/8/p7/rpK4p/1p3ppr/bQ1N1bqk w - -
White King must catch the black Rook (a3) like "cat and mouse".
It is one of these positions which leads you to a fatal conclusion, that only human can
think, and machines are stupid and there is needed an artificial intelligence to solve such problem.

At first I did it much weaker and moved black Pawn one step up.
[d]8/8/5p2/8/p7/rpK4p/1p3ppr/bQ1N1bqk w - -

Now I tried Stockfish 2.1.1 with VALUE_DRAW = -1.

Code: Select all

info depth 71
info currmove c3d4 currmovenumber 1
info nodes 1066926600 nps 248439 time 4294516
info currmove d1b2 currmovenumber 2
info currmove c3d2 currmovenumber 3
info nodes 1067469748 nps 248416 time 4297094
info currmove c3b4 currmovenumber 4
info depth 71 seldepth 28 multipv 1 score mate 32 lowerbound nodes 1068814645 np
s 248369 time 4303328 pv c3b4 a3a2 b4a5 a2a3 a5b6 a3a2 b6c7 a2a3 c7d6 a3a2 d6e7
f6f5 e7d6 a2a3 d6e5 a3a2 e5d4 a2a3 d4c5 a3a2 c5b4 a2a3 b4a3 f5f4 a3b4 f1d3 d1f2

After this Stockfish 2.1.1 with VALUE_DRAW = 0.
As it was excepted, it reaches a very high depth very quickly.

Code: Select all

info depth 95 seldepth 15 multipv 1 score cp 0 nodes 682474575 nps 238514 time 2
861359 pv c3d2 a3a2 d2e3 f6f5 e3f4 a2a3 f4e3 a3a2

But now it stoped and after 2 next hours I terminated the solving.

Of course I tried to solve the original position with black Pawn on f7 too.
Stockfish 2.1.1 with VALUE_DRAW = -1 shows mate in 44 on depth 74. Maybe it was a lucky.