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Subject: Re: SEE Function

Author: Tom Kerrigan

Date: 09:04:47 04/07/00

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On April 07, 2000 at 08:07:56, Robert Hyatt wrote:

>>(another 5 cycles). So doing SEE takes 10/2=5 times as long. This ignores the
>>fact that the SEE is probably much more expensive than 1 cycle, and the added
>>complexity/time of saving the list of captures/SEE values and then sorting them.
>Again, as I said, if I was designing a circuit to do a SEE, it would _still_
>be faster than software SEE.  And it could include as much as we wanted in
>terms of not overlooking pinned pieces or whatever... and _still_ run fast
>enough that it would be totally unnoticable in a chess engine...  IMHO of
>course.

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
make moves = 1 * 2
eval = 2 * 8
=> 53 cycles

So I bet SEE would slow the chip down by at least a factor of 2. I think that's
pretty noticable.

>Not when you read the details about the _last_ ASIC.  They added kpk endgame
>database to simply fill out the remainder of the chip...  which sounds like
>space wasn't a problem...  especially considering they used under 50% of the
>total eval hardware in the last version of DB, which suggests that he also added
>a _lot_ of feature detection hardware that was also done just to fill out the
>chip and was not used due to lack of time to test it.

Possibly. The PKP database doesn't impress me very much because it can probably
be extremely dense. I wouldn't be surprised if the move generator was larger
than the database.

-Tom



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