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Subject: Re: SEE Function

Author: Robert Hyatt

Date: 06:35:39 04/08/00

Go up one level in this thread


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...

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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