Author: José de Jesús García Ruvalcaba
Date: 08:18:50 02/08/99
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On February 07, 1999 at 18:30:17, Robert Hyatt wrote: >On February 07, 1999 at 13:12:01, José de Jesús García Ruvalcaba wrote: > >> >>Was crafty using the full 3+2 five men tablebases? > >yes... > > >>If the position after 100...Kc4 is a mate in 70 moves, then the position after >>101.Qe2+ should allow black a move which is a mate in at most 69 moves. But this >>position appeared *twice* before in the game. I wonder why crafty did not go for >>the mate in 69 *before*. > > >the problem is that at the point where it screwed up, it had a _real_ mate >in 73, or a bogus mate in 70 (bogus because it was a draw before the mate >could be played). So it went for the mate in 70 because the bug didn't let >it detect that the next opponent move would be a 3-fold repetition. > I see that crafty would never give up the h-pawn to reach a drawn QP vs Q ending. So I assume that the position after 96. Qxh5+ is won for black. I do not understand why, in a tablebase position, crafty allowed the same position to appear twice (however, I understand why it allowed the third repetition now). If crafty is in a won tablebase position, the distance to mate should decrease every move. > > >> >> Is it possible to have a queue of tablebase positions which need to be scored >>waiting for the harddisk to respond? > >not really. Because when I do a probe, I _know_ I will get a result. So >the search will definitely terminate here, with win/lose/draw scores. But I >can't really go on until I know which... because of alpha/beta.... > I see, the score is needed for the cutoffs. I realized that after giving it some thought at home. > > >>Currently there are no faster drives available, but there will... > >Certainly, although I doubt we are going to see much below 5ms for the >access time. There is still 'inertia' to overcome. But it wouldn't matter >if it was down to 1ms... because compare a 1ms disk read to a 2ns instruction >cycle time in a 500mhz processor... a difference of _one million_ that will >only get worse, not better...
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