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Subject: Re: SEE Function

Author: Tom Kerrigan

Date: 08:38:21 04/08/00

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On April 08, 2000 at 09:35:39, Robert Hyatt wrote:

>On April 08, 2000 at 01:34:50, Tom Kerrigan wrote:
>
>>On April 07, 2000 at 23:20:54, Robert Hyatt wrote:
>>
>>>>I still disagree. Didn't DB do a quick evaluation in ~4 cycles? So going back to
>>>>my example, the time to search 2/5 capture moves using MVV/LVA is:
>>>>
>>>>generate moves = 2 * 2
>>>>make moves = 1 * 2
>>>>eval = 2 * 8
>>>>=> 22 cycles
>>>>
>>>>And if you use SEE:
>>>>
>>>>generate moves = 2 * 5
>>>>SEE = 5 * 5
>>>I don't see 5*5 cycles in SEE.  I see 5 to enumerate the capturing pieces,
>>>5 to minimax the score.  10 total...  That is definitely cheaper than searching
>>>a node, which takes 10 clock cycles in DB.  Because in the above case you
>>>would have to search up to 10 nodes (5 captures per side) which is 100 clocks.
>>
>>I meant that the SEE would take on average 5 cycles, and it would have to be
>>done for 5 different moves.
>>
>>Searching a node might take 10 cycles for DB. And adding a SEE would add a
>>significant number of cycles to many of those nodes. That's exactly my point.
>>
>>-Tom
>
>
>Then we strayed...  my original comment was "the ultimate SEE would be too slow
>_unless_ it was designed as a special-purpose piece of hardware."  I have no
>doubt I could design a device to sit on the bus somewhere and handle SEE
>analysis, and do it inside the cycle time required to handle a single normal
>software SEE.  Probably at least 100 times faster, if not more...

Oh, whoops. I didn't realize that's what the original conversation was about.

-Tom

>
>and there is another point.  SEE can be used to reduce the overall size of
>the tree by 50%, easily.  Which would further widen the gap.  In hardware that
>does _everything_ it might well be a different issue...  Or the hardware will
>work differently than you expect...  IE the find-victim cycle is _not_ needed
>in SEE.  that goes out.  The find-aggressor cycle could, in one cycle, enumerate
>all the pieces that attack the target square.  So in one cycle, we enumerate all
>the black and white pieces that attack the square.  It _might_ require 5 cycles
>to do the swap calculations although I doubt it.  I believe that the typical
>SEE could be done in around 5 cycles which is not horribly slow...



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