Author: José Carlos
Date: 10:24:56 09/23/01
Go up one level in this thread
On September 23, 2001 at 12:45:41, Uri Blass wrote: >On September 23, 2001 at 12:15:35, José Carlos wrote: > >>On September 23, 2001 at 11:02:09, Uri Blass wrote: >> >>>On September 23, 2001 at 08:54:02, Gian-Carlo Pascutto wrote: >>> >>>>On September 23, 2001 at 05:29:51, Peter Berger wrote: >>>> >>>>> >>>>>[D]2b3k1/p4ppp/7q/2Q5/8/P3r1P1/1r4BP/R3R1K1 b - - bm Bb7; id "ECM.1197"; >>>>> >>>>>This one looks wrong. >>>> >>>>Nope...Bb7 is the fastest mate. >>> >>>What is the importance of finding the fastest mate. >>>There are programs that stop to search when they find one mate and I do not see >>>it as important for games if they know to find a shorter mate in the next move. >> >> This is wrong, partially. Of course playing programs are not mate provers, but >>if you stop the search in _any_ mate, you can play a check that leads to mate in >>5. The next move, check again, which leads to mate in 5. Then, another move that >>leads to mate in 6, and so on... You might lose on time meanwhile. > >I wrote > >"I do not see it as important for games if they know to find a shorter mate in >the next move" I wrote: "partially" >It means that the program can stop in the first mate and in the next move to >stop only when it finds a shorter mate. I agree here. >If the program can remember the full tree that proved the mate then it even does >not need to use time in the rest of the moves to find a shorter mate in the next >move. Agreed again. >If the tree is too big to remember for the program >then it means that the program needed a lot of time to find the mate and it >means that it had time and again there is no problem of losing on time unless >the program got into big time trouble in the last move and getting into a big >time trouble in one move is usually not logical(the only exception is if the >program thought that it is losing but it is not the case here). > >Uri I was only trying to point that it is dangerous to stop when a mate is found withot any other consideration. Of course, if you consider other things, you may solve it easyly. I know what I say because this _happened to me_ the first time I wrote Averno. As I've said before, I wrote it from scratch, and so I did a lot of stupid stuff, until I realized it was stupid, and figure out a smarter way to do it. I remember a game of version 0.14 where the program played Qh3+ Kh4 / Qh4+ Kh5 / Qh5 Kg6 etc. saying mate in 3 all the time. After that, I handled it in a less stupid, but still stupid way: remembering the pv when there was a mate score. Then, the opponent made a move out of the pv, and the stupidity begun again. When you do things like this, you feel the need to prevent others from doing the same :) Of course, there're zillions of ways to handle this smartly. José C.
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