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Subject: Re: Attack Table Question

Author: Heiner Marxen

Date: 06:21:21 03/23/04

Go up one level in this thread


On March 23, 2004 at 04:51:18, Uri Blass wrote:

>On March 23, 2004 at 02:24:38, Tony Werten wrote:
>
>>On March 22, 2004 at 19:21:42, Dann Corbit wrote:
>>
>>>On March 22, 2004 at 18:57:52, Uri Blass wrote:
>>>
>>>>On March 22, 2004 at 18:50:15, Dieter Buerssner wrote:
>>>>
>>>>>On March 22, 2004 at 18:16:37, martin fierz wrote:
>>>>>
>>>>>>of course i would also like to make an incremental update of that table, but i
>>>>>>decided against such an attempt because i couldn't figure out how to do it - or
>>>>>>rather, i devised a scheme for incremental updating which was so horribly
>>>>>>complicated that i decided not to use it - i'd rather have a slow engine with
>>>>>>little bugs and good maintainability than a fast engine with many bugs and low
>>>>>>maintainability :-)
>>>>>
>>>>>Reminds me of:
>>>>>
>>>>>"Debugging is twice as hard as writing the code in the first place. Therefore,
>>>>>if you write the code as cleverly as possible, you are, by definition, not smart
>>>>>enough to debug it." Brian W. Kernighan
>>>>>
>>>>>At the moment, I don't use attack tables at all. But I want them again. And I
>>>>>also only have a "build-from-scratch" routine. I also thought about incremental
>>>>>updates, and it seems like a very hard job. And the bad thing is, they seem to
>>>>>be especially useful at the leafs or close to the leafs. Perhaps I will start
>>>>>again with using them only closer to the root, for pruning/extension decisions.
>>>>>
>>>>>Regards,
>>>>>Dieter
>>>>
>>>>I update them incrementally.
>>>>I can only give a hint that I simply have a function to update incrementally
>>>>when I add a piece or delete a piece.
>>>>
>>>>I got this idea when I got the conclusion that having a function to update them
>>>>based on a move is a very hard task.
>>>
>>>I think I have the same idea:
>>
>>You left out the interesting part:
>>
>>>
>>>1.  Lift the piece off the board, and remove all of its influence
>>
>>1b for every slider attacking the fromsquare, extend its influence
>
>You miss the idea
>
>All the idea is that I consider no from square and no to square in updating the
>attack table.
>
>I look at a move as a sequence of add piece to square and remove the piece from
>square and I have function to update the attack table when I add piece or remove
>piece.

That is exactly the way I do it in Chest all the time.
Still, extending through a removed piece is necessary, as well as restricting
sliders at a newly placed piece.  But you knew that already  :-))

But e.p. and castling are just some more calls of these basic operations.
I have 3 basic operations:  put, delete and replace.

>Uri



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