Author: Michel Langeveld
Date: 07:58:35 01/13/04
Go up one level in this thread
On January 13, 2004 at 10:36:30, martin fierz wrote: >On January 13, 2004 at 10:28:54, Michel Langeveld wrote: > >>The idea of Nullmove is that you let a player have the right to do two moves >>during a game. If he can't win with this right then his position is really bad, >>and we count it as lost. >>-------------------------------------------------------------------------------- >>original >>6 318 343459 -8 b1c3 b8c6 i1h3 d7d6 h3f4 c8f5 >>7 1782 2188112 3 b1c3 d7d5 d2d4 c8f5 i1h3 i8h6 c1f4 >> >>nullmove with: if (!c && !nullmoved && depth - 1 - R > 0) >>6 215 227824 -8 b1c3 b8c6 i1h3 d7d6 h3f4 c8f5 >>7 859 1008458 3 i1h3 d7d5 d2d4 c8f5 b1c3 i8h6 c1f4 >> >>nullmove with :if (!c && !nullmoved) >>6 59 63778 -3 i1h3 d7d6 g1f3 i8h6 b1c3 b8c6 >>7 342 403509 3 i1h3 d7d5 d2d4 c8f5 c1f4 i8h6 b1c3 >> >>My question is do I have to protect that after a nullmove we go immediatly into >>quiesce or can I live without this protection? > >i don't protect against it. as you can see you get a massive speedup without it. Yes I can see it is huge. I was thinking a bit more when the if (x >= beta) return beta is triggered. [d]rnbqkbnr/1ppp1ppp/p7/4p3/4P3/5Q2/PPPP1PPP/RNB1KBNR w KQkq - 0 1 In this position. If white plays f1c4 then we do a nullmove and white can move again. Then we can win with Qxf7 mate. We have done the variation then f1c4 <null> f3q7# which is 3 ply This mate score is returned as -10000 + ply (does a nullmove has to increase th ply count?) which is -10000 + 3 = -9997 x = 9997 f3q7 is takebacked x = -9997 and the nullmove is takebacked x is then not > beta probably so this example does not work. Or did I gave now an excellent example of Bruce Moorelands thread extensions. >what i (and many others of course, before me) do is to generate checks at the >first ply of qsearch. so if you nullmove, go to qsearch, you probably find out >whether you're being mated or not. I hope I can make an ultra fast generatechecks for tscp and expirement with it. >if you don't have checks on the first ply of >QS, you will happily cut off in a position where your opponent can mate in one. > >so doing checks in QS is a way of protecting yourself here. > >then again lots of people don't do checks in QS - a well-known example for this >is crafty.
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