Author: Heiner Marxen

Date: 10:57:35 04/17/01

Go up one level in this thread

On April 17, 2001 at 13:12:22, leonid wrote: >On April 17, 2001 at 11:13:02, Heiner Marxen wrote: > >>On April 17, 2001 at 07:43:30, leonid wrote: >> >>>Hello! >>> >>>If you like to solve very "regular" mate position, then you have one. >>> >>>[D]R7/4P1Pq/1rR5/2pb1rnk/1Q3B2/4Nn2/1PB2Np1/2K1b1Q1 w - - >>> >>>Please, indicate your result. >>> >>>Thanks, >>>Leonid. >> >>According to Chest there are two key moves for mate in 7 moves: >> >>Qxg2 Bd2+ Qxd2 Bxc6 g8=Q Qxg8 Rxg8 Bd5 e8=Q+ Bf7 Nxf5 Nd4 Rxg5# >>Rh8 Bd2+ Qxd2 Be4 e8=Q+ Rf7 Qxf7+ Nxf7 Qd5+ Bf5 Rxh7+ Nh6 Rhxh6# >> >>(K7/600, 350MB hash, 9.3 minutes) >> >>Heiner > >Thanks, Heiner! My program demonstrate the worst possible branching factor for >this position. Even for seeing the 6 moves by brute force it took already 38 min >(Celeron 600. No hash). Only after your indication I went to see 7 moves by >brute force. It took for mine hefly 1 hours 5 min. And this is after my last >improvement that cut 6 moves brute force search already by 48%. > >Previously this position my solved by selective search in 10 moves. > >Leonid. Hi Leonid, From depth=6 in 38 minutes to depth=7 in 1h5min is a factor of less than 2. Even with the 48% improvement, the factor is just 4. That is quite different from Chest's timing (see below), and is unexpectedly low (for me). My program shows a branching factor significantly larger than usual, but not "worst possible". Here is the timing info for increasing depths: depth seconds speed hash in hash out # 1 0.00 0.87 1- 0 # 2 0.01 1.00 1- 0 # 3 0.03 0.97 83- 0 # 4 0.26 1.06 907- 0 # 5 2.59 1.30 13215- 0 # 6 31.77 1.58 184695- 0 # 7 559.19 1.81 3425552- 2347 559.19 / 31.77 = 17.60 which is much smaller than 79 (initial legal moves). Here is statistics over remaining depth: moves quotient depth attacker defender att def mvx 7: 79 192 [ 79.000 2.430] mvskip lvskip mvx 6: 1167 1863 [ 6.078 1.596] 5 mvx 5: 22875 25690 [ 12.279 1.123] 679 mvx 4: 299329 334138 [ 11.652 1.116] 7313 4 mvx 3: 3752287 3769416 [ 11.230 1.005] mvx 2: 22524391 7352320 [ 5.976 0.326] mvx 1: 2394158 0 [ 0.326 ] The "refutation table" shows which defender moves were chosen top level. Selecting the "right" defender moves is important for small search trees: refu 1: e8=Q+ Bf7 [ 6-] solu 4: Nf7 [ 5+] solu 5: Kh4 [ 1+] refu 2: e8=B+ Bf7 [ 6-] solu 6: Nf7 [ 5+] solu 7: Kh4 [ 1+] refu 3: Rh6+ Qxh6 [ 6-] refu 4: Qh1+ gxh1=Q [ 6-] refu 5: Qh2+ Nxh2 [ 6-] refu 6: g8=Q Bd2+ [ 6-] refu 7: g8=N Bd2+ [ 6-] refu 8: g8=R Bd2+ [ 6-] refu 9: g8=B Bd2+ [ 6-] refu 10: e8=N Bd2+ [ 6-] refu 11: e8=R Bd2+ [ 6-] refu 12: b3 Bd2+ [ 6-] refu 13: Nd3 Bd2+ [ 6-] refu 14: Nfd1 Bd2+ [ 6-] refu 15: Ne4 Bd2+ [ 6-] refu 16: Nfg4 Bd2+ [ 6-] refu 17: Nh3 Bd2+ [ 6-] refu 18: Nh1 Bd2+ [ 6-] refu 19: Nc4 Bd2+ [ 6-] refu 20: Nxd5 Bd2+ [ 6-] refu 21: Ned1 Bd2+ [ 6-] refu 22: Nxf5 Bxf2 [ 6-] solu 9: Bd2+ [ 6+] solu 10: Nxg1 [ 3+] solu 11: Nd2 [ 2+] solu 12: Nd4 [ 2+] solu 13: Ne5 [ 2+] solu 14: Qxf5 [ 5+] solu 15: Ra6 [ 3+] solu 16: Qxg7 [ 3+] solu 17: cxb4 [ 5+] solu 18: Rxb4 [ 5+] solu 19: Bxb4 [ 5+] solu 20: Rxc6 [ 6+] solu 21: Bxc6 [ 6+] refu 23: Nf1 Bd2+ [ 6-] refu 24: Neg4 Bd2+ [ 6-] refu 25: Nxg2 Bd2+ [ 6-] refu 26: Bxg5 Rxb4 [ 6-] solu 22: Bd2+ [ 6+] solu 23: Nxg1 [ 1+] solu 24: Ne5 [ 1+] solu 25: Nd2 [ 1+] solu 26: Nd4 [ 3+] solu 27: Qxg7 [ 1+] solu 28: Ra6 [ 1+] solu 29: cxb4 [ 6+] refu 27: Bg3 Bd2+ [ 6-] refu 28: Bh2 Bd2+ [ 6-] refu 29: Be5 Bd2+ [ 6-] refu 30: Bd6 Bd2+ [ 6-] refu 31: Bc7 Bd2+ [ 6-] refu 32: Bb8 Bd2+ [ 6-] refu 33: Bd3 Bd2+ [ 6-] refu 34: Be4 Bd2+ [ 6-] refu 35: Bxf5 Rxc6 [ 6-] solu 30: Bd2+ [ 6+] solu 31: Nxg1 [ 4+] solu 32: Nd4 [ 2+] solu 33: Nd2 [ 2+] solu 34: Ne5 [ 2+] solu 35: Rxb4 [ 2+] solu 36: Qxf5 [ 5+] solu 37: Qxg7 [ 2+] solu 38: Ra6 [ 2+] solu 39: cxb4 [ 2+] solu 40: Bxb4 [ 2+] refu 36: Bb1 Bd2+ [ 6-] refu 37: Bd1 Bd2+ [ 6-] refu 38: Bb3 Bd2+ [ 6-] refu 39: Ba4 Bd2+ [ 6-] refu 40: Rd6 Bd2+ [ 6-] refu 41: Re6 Bd2+ [ 6-] refu 42: Rf6 Bd2+ [ 6-] refu 43: Rg6 Bd2+ [ 6-] refu 44: Rxb6 Bd2+ [ 6-] refu 45: Rc7 Bd2+ [ 6-] refu 46: Rcc8 Bd2+ [ 6-] refu 47: Rxc5 Bd2+ [ 6-] refu 48: Rb8 Bd2+ [ 6-] refu 49: Rac8 Bd2+ [ 6-] refu 50: Rd8 Bd2+ [ 6-] refu 51: Re8 Bd2+ [ 6-] refu 52: Rf8 Bd2+ [ 6-] refu 53: Rg8 Bd2+ [ 6-] refu 54: Rh8 Bd2+ [ 5-] solu 41: Bd2+ [ 6+] solu 42: Nxg1 [ 5+] solu 43: Nd2 [ 2+] solu 44: Nd4 [ 2+] solu 45: Ne5 [ 2+] solu 46: Ra6 [ 4+] solu 47: cxb4 [ 4+] solu 48: Rxb4 [ 2+] solu 49: Bxb4 [ 4+] solu 50: Rxc6 [ 6+] solu 51: Bxc6 [ 6+] solu 52: Qxh8 [ 2+] solu 53: Rxf4 [ 4+] solu 54: Bxf2 [ 5+] solu 55: c4 [ 4+] solu 56: Ba2 [ 4+] solu 57: Rb7 [ 2+] solu 58: Bb3 [ 4+] solu 59: Be4 [ 5+] solu 60: Nf7 [ 2+] solu 61: Nh4 [ 5+] solu 62: Bf7 [ 4+] solu 63: Rf7 [ 2+] solu 64: Kh4 [ 2+] solu 65: Rb8 [ 2+] solu 66: Rb5 [ 2+] solu 67: Ne6 [ 2+] solu 68: Ne4 [ 1+] solu 69: Nh3 [ 1+] solu 70: Nh2 [ 2+] solu 71: Bc3 [ 4+] solu 72: Be6 [ 5+] solu 73: Bg8 [ 5+] solu 74: Bc4 [ 4+] solu 75: Re5 [ 2+] solu 76: Rf6 [ 5+] solu 77: Rf8 [ 2+] solu 78: Qh6 [ 1+] refu 55: Ra7 Bd2+ [ 6-] refu 56: Ra6 Bd2+ [ 6-] refu 57: Ra5 Bd2+ [ 6-] refu 58: Ra4 Bd2+ [ 6-] refu 59: Ra3 Bd2+ [ 6-] refu 60: Ra2 Bd2+ [ 6-] refu 61: Ra1 Bd2+ [ 6-] refu 62: Qf1 Bd2+ [ 6-] refu 63: Qgxe1 g1=Q [ 6-] refu 64: Qxg2 Bd2+ [ 5-] solu 79: Bd2+ [ 6+] solu 80: Ng1 [ 1+] solu 81: Nd2 [ 1+] solu 82: Nd4 [ 1+] solu 83: Ne5 [ 2+] solu 84: Qxg7 [ 1+] solu 85: Ra6 [ 1+] solu 86: cxb4 [ 1+] solu 87: Rxb4 [ 1+] solu 88: Bxb4 [ 1+] solu 89: Rxc6 [ 6+] solu 90: Bxc6 [ 6+] solu 91: Rxf4 [ 2+] solu 92: Bxf2 [ 1+] solu 93: c4 [ 1+] solu 94: Rb7 [ 1+] solu 95: Bb3 [ 1+] solu 96: Ba2 [ 1+] solu 97: Be4 [ 1+] solu 98: Nf7 [ 1+] solu 99: Nh4 [ 1+] solu 100: Bf7 [ 1+] solu 101: Rf7 [ 1+] solu 102: Kh4 [ 1+] solu 103: Rb8 [ 1+] solu 104: Rb5 [ 1+] solu 105: Ne6 [ 1+] solu 106: Ne4 [ 1+] solu 107: Nh3 [ 1+] solu 108: Nh2 [ 2+] solu 109: Bc3 [ 1+] solu 110: Be6 [ 5+] solu 111: Bg8 [ 1+] solu 112: Bc4 [ 1+] solu 113: Re5 [ 1+] solu 114: Rf6 [ 4+] solu 115: Rf8 [ 1+] solu 116: Qh6 [ 1+] solu 117: Qg6 [ 3+] solu 118: Qh8 [ 1+] solu 119: Qg8 [ 1+] refu 65: Qc4 Bd2+ [ 6-] refu 66: Qd4 Bd2+ [ 6-] refu 67: Qe4 Bd2+ [ 6-] refu 68: Qa4 Bd2+ [ 6-] refu 69: Qb5 Bd2+ [ 6-] refu 70: Qxb6 Bd2+ [ 6-] refu 71: Qb3 Bd2+ [ 6-] refu 72: Qxc5 Bd2+ [ 6-] refu 73: Qa3 Bd2+ [ 6-] refu 74: Qc3 Nxg1 [ 6-] refu 75: Qd2 Bxd2+ [ 6-] refu 76: Qbxe1 Rxc6 [ 6-] solu 1: Nd4 [ 2+] solu 2: Nd2 [ 2+] solu 3: Nxe1 [ 2+] solu 120: Nxg1 [ 6+] solu 121: Ne5 [ 2+] solu 122: Qxg7 [ 6+] solu 123: Ra6 [ 6+] refu 77: Qa5 Bd2+ [ 6-] refu 78: Kd1 Bb3 [ 6-] solu 8: Ne4 [ 5+] refu 79: Kb1 Nd2+ [ 6-] Have a nice day! Heiner

- Re: Mate that every program will solve...
**leonid***15:06:54 04/17/01*

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