Author: Heiner Marxen
Date: 04:17:48 01/19/01
Go up one level in this thread
On January 18, 2001 at 22:06:37, leonid wrote: >On January 18, 2001 at 19:13:22, Paul wrote: > >>On January 18, 2001 at 19:01:08, Pete Galati wrote: >> >>>On January 18, 2001 at 18:44:05, leonid wrote: >>> >>>>Hi! >>>> >>>>If you would like to find a mate here is one position. It is very easy to solve >>>>but not that simple to find shortest mate. >>>> >>>>I failed here even in 3 hours to find shortest mate through brute force search. >>>>Maybe you will have better chance. >>>> >>>> 1k4q1/1pppPr2/PbbP1N1n/QP2rn1R/1q6/1q2RBB1/q1q2PPP/6NK black to go >>>> >>>>Leonid. >>> >>>Is this the right position? >>> >>>[D]1k4q1/1pppPr2/PbbP1N1n/QP2rn1R/1q6/1q2RBB1/q1q2PPP/6NK b - - 0 1 >> >>If so, then mine says it's a mate in 10 for black starting with Nxg3+ ... >>It looks like a daily reverse auction ... Anyone lower, anyone? :) >> >>Paul > >Position is exact and response 10 moves must be or shortest possible, or very >close move. Actually my program solved this position through selective search in >11 moves. Solution was instant. Finding shortest mate is the other story. >Through brute force program said in 8 mate is not there. Only 9 still could be >looked. > >I found that branching factor was terrible to see 9 moves. AMD 400Mhz. > >8 moves - 2h 44 min. >7 moves - 2 min 48 sec. >6 moves - 7 sec. > >Leonid. Chest says "no mate in 9" in 180 sec (3 min) (K7/600 350MB TT) My branching factor is not that bad (depth, seconds, speed, TT-nodes in-out) # 1 0.00 0.87 1- 0 # 2 0.00 1.00 1- 0 # 3 0.01 0.97 45- 0 # 4 0.07 1.07 338- 0 # 5 0.37 1.27 1971- 0 # 6 1.78 1.66 9653- 0 # 7 9.25 1.99 52004- 0 # 8 41.00 2.45 261032- 0 # 9 180.08 2.97 1253899- 1 May be that your move ordering for the defender (here: white) is not so good. Aggresive defender moves are important to reduce the size of the search trees. You seem to like bizarre positions :-) Heiner
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