Author: scott farrell
Date: 18:46:41 09/05/02
Hi guys,
I hope someone can give me some ideas, or can understand this pattern.
this is the fen position
7k/pp3p1p/1np5/5N2/1P2P1NR/7P/3r2PK/2r5/ b - - 0 50
clearly the best move is Nd7 (aka B6D7)
Rcc2 (aka c1c2) is not too bad either
The rest pretty much lead to mate.
My program works that out pretty quickly, but changes its mind during depth 10
to D2C2.
When searching depth 11 - its sees that D2C2 leads straight to being mated (in 2
plies - mate in 1 - I think). The move ordering obviously gets screwed up, and
it does an almost reverse alpha-beta search.
I assume this is a bug somewhere in my search, does anyone have any ideas?
this is my programs analysis:
d6/8(3) 4.28 0.38secs 6820 C1C2 G4E3 C2A2 H4G4 B6D7 G4G7
->6/10(3) 4.28 0.71secs 38971 C1C2 G4E3 C2A2 H4G4 B6D7 G4G7
d7/12(3) 4.59 0.88secs 55850 C1C2 F5E3 C2B2 G4F6 H8G7 F6H7 B2B4
d7/12(4) 4.85 1.7secs 137123 B6D7 F5H6 F7F6 G4E3 H8G7 H6F5
->7/12(4) 4.85 1.7secs 137141 B6D7 F5H6 F7F6 G4E3 H8G7 H6F5
d8/12(3) 4.22 1.98secs 162918 B6D7 F5H6 F7F6 H4H5 C1C2 H6F7
->8/14(4) 4.22 4.01secs 364580 B6D7 F5H6 F7F6 H4H5 C1C2 H6F7
d9/16(4) 4.69 6.87secs 654405 B6D7 H4H6 C1C2 G4E3 C2B2 H6D6 D2D6
->9/16(4) 4.69 7.36secs 711939 B6D7 H4H6 C1C2 G4E3 C2B2 H6D6 D2D6
d10/18(4) 3.86 12.3secs 1292913 B6D7 H4H6 C6C5 B4B5 C1E1 F5D6 E1F1 D6C4 D2C2
H6D6
d10/18(4) 3.9 19.17secs 1941731 D2C2 H2G3 C6C5 B4C5
->10/24(4) 3.9 30.43secs 3164993 D2C2
d11/19(2) -501.99 30.59secs 3178776 PV miss at root:D2C2
d11/20(3) -1.03 41.52secs 4470207 D2G2 H2G2 C1C2 G2F3 C2C3 F3E2 B6D7 F5D6
H8G7 D6B7 C3G3 G4F2 G7F6
d11/20(3) 3.89 43.01secs 4611313 C1C2 F5E3 C2B2 G4F6 H8G7 E4E5 G7F8 F6H7
d11/22(4) 4.59 116.28secs 11658630 B6D7 G4E3 D7E5
This is from crafty:
({10:Mat06} 35. ... Ra2 36. Nf6 Rxg2+ 37. Kxg2 Rc2+ 38. Kg3 Rc3+ 39. Kg4 Rxh3
40. Rxh3 Nc4 41. Rxh7# +-)
(yes beleive it or not, my engine played Ra2 - a few months back without
extensions)
({10:-5.14} 35. ... Nd7 36. Rh6 Rb1 37. Rd6 Rxd6 38. Nxd6 Kg7 39. Nxb7 h5 40.
Ne3 Rxb4 -+)
({10:-1.74} 35. ... Rcc2 36. Nf6 Rxg2+ 37. Kh1 Rh2+ 38. Kg1 Rcg2+ 39. Kf1 Rg7
40. Nxg7 Kxg7 41. Ne8+ Kg8 42. Nd6 Rb2 43. Rf4 Rb1+ 44. Kg2 Rb2+ 45. Kf3 -+)
({10:+2.46} 35. ... Nd5 36. exd5 Rcc2 37. Nge3 Rb2 38. Re4 h5 39. dxc6 bxc6 40.
Ng3 c5 41. bxc5 +-)
normal moves:
C1H1,C1G1,C1F1,C1E1,C1D1,C1B1,C1A1,C1C2,C1C3,C1C4,C1C5,D2D1,D2G2,D2F2,D2E2,D2C2,
D2B2,D2A2,D2D3,D2D4,D2D5,D2D6,D2D7,D2D8,C6C5,B6C4,B6A4,B6D5,B6D7,B6C8,B6A8,H7H5,
H7H6,F7F6,A7A5,A7A6,H8G7,H8G8,
OUT OF CHECK moves:
C1H1,C1G1,C1F1,C1E1,C1D1,C1B1,C1A1,C1C2,C1C3,C1C4,C1C5,D2D1,D2G2,D2F2,D2E2,D2C2,
D2B2,D2A2,D2D3,D2D4,D2D5,D2D6,D2D7,D2D8,C6C5,B6C4,B6A4,B6D5,B6D7,B6C8,B6A8,H7H5,
H7H6,F7F6,A7A5,A7A6,H8G7,H8G8,
qsearch moves:
D2G2,
sideotmove token:
7k/pp3p1p/1np5/5N2/1P2P1NR/7P/3r2PK/2r5/ b - - 0 50
searchProbeThread starting
start search from 6 to 30
Scott
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