Author: F. Huber
Date: 09:59:29 01/06/05
Go up one level in this thread
On January 06, 2005 at 12:20:13, Heiner Marxen wrote: >On January 05, 2005 at 16:15:22, F. Huber wrote: > >>On January 05, 2005 at 14:02:58, Richard Pijl wrote: >> >>>On January 05, 2005 at 13:47:09, Kurt Utzinger wrote: >>> >>>>Much too easy for any chess program I think. Or can you find >>>>a modern engine being unable to solve this within 0 to some seconds? >>>>Kurt >>> >>>I only tried a few, and all were able to solve it in 1 second or less on my >>>machine. >>>Now a question for the mate-solvers: Is this a mate in 20, or can a faster mate >>>be found? >>>Richard. >> >>Hi Richard, >> >>I´ve tried it now in brute-force mode with ´Gustav 3.0´ up to depth 13, but >>with a branching factor of about 2.5 it would take too long, if it´s really >>a mate in 20 (so at least it´s above 13). >>Chest (also in brute force) is much slower for this position ... >> >>Of course all this is _without_ any EGTBs, since both programs don´t support >>them - although: Heiner Marxens private development version of Chest seems to >>already have implemented it, so maybe Heiner could try this problem. > >Hello Franz, > >I've started it on my Athlon 1500+ with all 3&4 piece TBs, and very few 5-piece >TBs. Depth 12 needs a minute and shows a factor around 3 between depths, >so I'm not sure this has any hope. > >Which 5-piece tables would be most useful here? >I could try to get some more... >[depth 13: 244 secs, factor 3.79... :-( ] Hello Heiner, I´m not absolutely sure, but I´d guess KNPKP would be the best one (since white can quite simply force it to remove both queens and win the black knight). Of course 6-men TBs would be still better, but probably they are not supported yet in your current version. (?) But IMO this is much more a position for a normal chess engine (and EGTBs) than for a mate solver, and (again only IMO) I don´t really see the need of EGTB- support in a mate solver at all - there are much too little positions which would profit by it, but OTH it will probably slowdown the search. What´s really surprising with this position, is that Chest is much slower than Gustav here (which is absolutely not usual!), and furthermore that the branching factor in Chest is significantly higher than that of Gustav (being about 2.5)!? Regards, Franz.
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