Author: Stuart Cracraft
Date: 12:18:22 09/25/04
Go up one level in this thread
On September 25, 2004 at 14:59:07, Zach Wegner wrote: >On September 25, 2004 at 14:46:06, Peter Fendrich wrote: > >>On September 25, 2004 at 13:51:39, Zach Wegner wrote: >> >>>>When you find a mate it first will get x > beta... Right? >>>>Then you will never reach the following statement. >>>>/Peter >>> >>>No, this is when the side to move gets mated, giving a score < -MATE + MAXPLY. >>> >>>Zach >> >>Right but I meant that return beta will not show -MATE+MAXPLY one ply up. >>This nulmove only code, however, and the answer is dependent of what's happening >>in the alpha/beta stuff later on... >>/Peter > >Sorry, I misunderstood you. But the mate threat code is typically not (x < -MATE >+ MAXPLY) but (x == -MATE + ply + 2) so that first when the side to move is >mated it returns -MATE + ply (ply being 2 more than where the nullmove is >called) and then at ply + 1 it returns MATE - ply (this is a simple >change-return val instead of beta at a fail high) But doesn't returning -MATE+ply from search() mean that the program might postpone making a mate since it is not returning -MATE+depth and so the ply is increasing and so more credit for deeper mates whereas depth is decreasing so more credit for more shallow mates? Stuart
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