Author: leonid
Date: 16:44:02 01/19/01
Go up one level in this thread
On January 19, 2001 at 17:54:10, Heiner Marxen wrote: >On January 19, 2001 at 17:06:44, leonid wrote: > >>On January 19, 2001 at 15:32:49, Heiner Marxen wrote: >> >>>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. >>> >>>Now, with the correct side to move, Chest has still found "no mate in 9". >>>But the timing indicate an unusually large branching factor: >>># 1 0.00 0.87 1- 0 >>># 2 0.01 1.00 1- 0 >>># 3 0.02 0.96 89- 0 >>># 4 0.06 1.09 437- 0 >>># 5 0.27 1.30 1693- 0 >>># 6 2.04 1.38 6662- 0 >>># 7 31.09 1.49 63238- 0 >>># 8 824.56 1.75 1256916- 3 >>># 9 24061.56 2.19 37677207- 28929306 >>>(depth, seconds, speed, nodes in-out) on a K7/600 (350 MB TT) >>> >>>That are already 6.7 hours. I'm not sure I will wait until the mate in 10 >>>arrives. We can expect over 8 days from the above data. The last two >>>lines have indicate an effective branching factor of 29.2. >>>Although this is a bit better than Leonid's factor 60, it is still quite >>>a bit too heavy. >>> >>>Heiner >> >>So it was really 10 moves positions! >> >>Your branching factor is much better that mine. Only position? Better move >>ordering? I don't know. It could be even hash table. And how after your >>experience hash helps in branching factor? If there ever existe some difference >>at all. >> >>Can see that in general our branching factor have the same tendency for this >>position. It grows to the worst with the number of plys to be seen. In mine it >>goes this way: >> >>4 moves - 0.1 sec >> branching = 8.8 >0.27 / 0.06 = 4.5 >>5 moves - 0.88 sec >> branching = 8.2 >2.04 / 0.27 = 7.55 >>6 moves - 7.25 >> branching = 23 >31.09 / 2.04 = 15.24 >>7 moves - 2 min 47 sec >> branching = 59 >824.56 / 31.09 = 26.52 >>8 moves - 2 h 43 min 56 sec >> >>Leonid. > >Since increasing depth seems to help me as compared to you, >I suspect much of it is caused by the TT. My hit rate is not large, >8.6% normal hits and 18.2% hits for ETC (enhanced transposition cutoffs). >But with some depth left to go that can have quite an effect. Heiner, please don't use with me abreviation! I just don't know what it is TT. If you will write something in German, or even in Chinese - never mind! I have all dictionaries in my room to help me. I have no chance with abreviations. Only few I learned already by heart. >To measure the effect of good move ordering, I would have to replace it >with another one, and re-run. I'm too lazy for this just now. >I suspect that you will at least also prefer check moves and captures, >so for this special problem we may do comparatively equal: white has >left quite some pieces to be agressive in that simple way. > >BTW, here are my branching factors inside the "no mate in 8": >mvx 8: 87 87 [ 87.000 1.000] 1 >mvx 7: 438 533 [ 5.034 1.217] >mvx 6: 1713 2259 [ 3.214 1.319] 1 >mvx 5: 7444 9227 [ 3.295 1.240] 154 4 >mvx 4: 70334 74945 [ 7.623 1.066] 2052 5 >mvx 3: 1469915 1314821 [ 19.613 0.894] >mvx 2: 33639291 23346271 [ 25.585 0.694] >mvx 1: 4117503 0 [ 0.176 ] > >Just implement your TT. You will love the effect! If TT have something to do with hash table then I expect to come to this sonner or later. Mainly when complet rewriting for Linux will start. I dream already to start my new system writing! But probably I must wait up to the end of Summer. Today went reading about new 64 bits chip. Could never understand if this Intel's chip already came, or close to be produced but it give wonderful impression! 128 new 64 bits registers to play with. When finally it will be no more rumor but real chip for all of us!!!! Leonid. >Heiner
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