Author: Tony Werten
Date: 11:11:40 11/22/02
Go up one level in this thread
On November 22, 2002 at 12:58:42, Andreas Herrmann wrote: >On November 22, 2002 at 11:35:38, Tony Werten wrote: > >>On November 22, 2002 at 10:39:16, Uri Blass wrote: >> >>>On November 22, 2002 at 10:30:34, Robert Hyatt wrote: >>> >>>>On November 22, 2002 at 07:21:13, Uri Blass wrote: >>>> >>>>>On November 22, 2002 at 05:50:09, Omid David Tabibi wrote: >>>>> >>>>>>Vincent, >>>>>> >>>>>>You haven't read the article yet. READ IT. I have described everything I have >>>>>>done quite clearly, and have presented the results. All the node counts are also >>>>>>available at my website. >>>>>> >>>>>>Regarding your checkmate question: except for the "Mate in 4" and "Mate in 5" >>>>>>positions which I was interested to know only if the checkmating was found or >>>>>>not, in all other test positions (ECM, WCS, Neishtadt) the search was conducted >>>>>>to the mentioned depth even if a checkmate is found at eariler plies. This was >>>>>>done in order to ensure that the fixed depth results are comparable in terms of >>>>>>tree size. >>>>>> >>>>>>Omid. >>>>> >>>>>What do you search after finding a mate? >>>>>Does genesis search for a shorter mate and in this case does it knows not to >>>>>search when it get ply that means that no shorter mate can be found? >>>>> >>>>>Movei simply stop searching after finishing an iteration with mate score. >>>>> >>>>>Uri >>>> >>>> >>>>I would suspect he does like most everyone else. Search until you reach depth >>>>2*N-1 where N is the mate depth as in mate in 9. I need to search 17 plies to >>>>verify that no shorter mate than mate in 9 exists... >>> >>>I do not know what most do but I do not care after finding a mate to find the >>>shorter mate. >>> >>>The result is the same even if I do not find the shortest mate. >>>I care only to finish the iteration. >> >>You'll care when you add tablebase support. >> >>When there are 6 pieces on the board and your program sacrifies his queen to >>find a checkmate in 123, you'd wish it had searched a bit longer to find the >>mate in 4. > >Hi Tony, > >but then you must be in depth 245 to cut the search by checkmate in 123 and >search abort after 2*N-1. No, if you can't find anything better then you take the checkmate in 123. But if you allocated fe 2 minutes, you can spend that time to find a shorter one. I started with this idea when I saw Fritz make exactly this mistake. It's not too bad, it just looks silly. > >In previous versions i have also finished the search after 2*N-1. In my current >version i finish my search after 2*N+2, because of Nullmove and other pruning >algos. But it's mainly interresting to search a little bit deeper if there was >found a mate for the opponent, perhaps in some rare cases a draw will be find 2 >or 3 plys deeper. > >Andreas > >PS: Thanks again for your DLL. Works fine :) You're welcome. Please don't forget to drop Eugene an email. The dll gives acces to his tables, so you should let him know/ask permission. (Theoreticly the latter, practicly the first ) Tony
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