Author: Tony Werten
Date: 06:01:09 01/07/03
Go up one level in this thread
On January 07, 2003 at 08:46:56, Ed Schröder wrote: >On January 07, 2003 at 07:31:35, Tony Werten wrote: > >>On January 07, 2003 at 07:17:27, Ed Schröder wrote: >> >>>On January 07, 2003 at 06:48:50, Tony Werten wrote: >>> >>>>On January 07, 2003 at 05:47:37, Ed Schröder wrote: >>>> >>>>>On January 07, 2003 at 05:05:31, Tony Werten wrote: >>>>> >>>>>>Hi Ed, >>>>>> >>>>>>your board tables seem to ignore xray attacks. >>> >>> >>>>>xray attacks are done, it's only not mentioned as I thought it would be >>>>>self-understood. >>> >>>>I don't see how they are combined with the boardtables to find hanging pieces. >>>> >>>>Adding them as normal attacks will make you go wrong as often as not counting >>>>them at all, is my guess. >>> >>>Let's go through a couple of xray examples: > > >>I understand (I think). Ignore low pieces through high pieces, but add high >>through low as a normal attack. Seems a cheap way. One question though. Will it >>go wrong in this position (g8) ? > >Rebel will report that G8 is hanging, expected gain 5.00 > >It's all in those bits, there are a few complicated cases you don't get the >right status, but over 99.9% will get it right. I had a sudden brainwave and understand now. That's a nice trick ! And a lot cheaper than SEE, specially when looking for safe squares to move a piece to. Tony > >Ed > > >>[d]r2qkbqr/pbppp1pp/1pn2p2/3Q4/2B5/2P1P3/PP1P1PPP/RNB1K1NR b KQkq - >> >>Tony >> >>> >>>[d]rn1qkbnr/pbppp1pp/1p3p2/8/2B5/1QP1P3/PP1P1PPP/RNB1K1NR b KQkq - >>> >>>The knight on G8 is hanging, 2 attackers, one defender, the lowest attacking >>>piece is a bishop. You can extract this from the bit settings. >>> >>> >>> >>> >>> >>> >>> >>>[d]r2qkbnr/pbppp1pp/1pn2p2/3Q4/2B5/2P1P3/PP1P1PPP/RNB1K1NR b KQkq - >>> >>>The knight on G8 is not hanging because the lowest attacking piece is a Queen. >>> >>> >>> >>> >>>[d]rn2kbnr/pppqpppp/3pb3/8/8/P1N4N/1PPPPPPP/R1BQKB1R w KQkq - >>> >>>The white knight on H3 is well covered, 2 attackers, 2 defenders, the lowest >>>attacking piece is a bishop, but its defender is lower, a pawn. The white bishop >>>on F1 looks through G2 to H3. >>> >>>Hope this helps, >>> >>>Ed >>> >>> >>> >>>>Tony >>>> >>>>> >>>>> >>>>>>Is that because it doesn't matter too much, or because it's mainly used for move >>>>>>ordering ( so it's only less effective but not wrong ) ? >>>>> >>>>>I use xray also for evaluation, for instance for mobilty, king safety, so xray >>>>>must be done and in an accurate way, I will write a little about it in the >>>>>mobility section. >>>>> >>>>>Ed >>>>> >>>>>>Or do you handle xray attack as a normal attack ? >>>>> >>>>> >>>>>>Cheers, >>>>>> >>>>>>Tony
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