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Subject: Re: Evaluation in Rebel

Author: Tony Werten

Date: 04:31:35 01/07/03

Go up one level in this thread


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) ?

[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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