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
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