Author: allan johnson
Date: 01:59:00 09/06/02
Go up one level in this thread
On September 05, 2002 at 21:46:41, scott farrell wrote:
>Hi guys,
>
>I hope someone can give me some ideas, or can understand this pattern.
>
>this is the fen position
>
>[D]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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