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Subject: Re: 2^250 and 2^400

Author: Keith Ian Price

Date: 10:34:36 06/28/98

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On June 27, 1998 at 15:48:19, Robert Hyatt wrote:

>On June 27, 1998 at 15:32:50, Keith Ian Price wrote:
>
>>2^250=
>>1809251394333065553493296640760748560207343510400633813116524750123642650624
>>
>>2^400=
>>2582249878086908589655919172003011874329705792829223512830659356540647622016841194629645353280137831435903171972747493376
>>
>>The latter number is greater than the estimated number of atoms in the universe,
>>so making the gates may be troublesome.
>>
>>In case you were really interested.
>>
>>kp
>
>
>never thought otherwise.  But sometimes it is difficult to explain simple
>concepts to Vincent without bringing out elementary math facts.  He is of
>the opinion that to design a circuit you lay all gates out in a linear line,
>one gate per level, so that gate-delays == # of gates.  I am *trying* to
>explain to him that this is *not* the way you design fast hardware.  You
>lay things out horizontally whenever possible, to take advantage of the
>inherent parallelism in such hardware logic.
>
>so far, my lectures are going over his head...  But I'll keep trying.
>But, as you notice, given 400 gate delays lets me put a *huge* amount
>of parallel stuff together...

Yes, I saw that you were doing that, but in real terms, given 2.4 million
transistors on the chip (I think I recall that that is close), and with 1/3 of
the chip devoted to move generation and EGTB and tunable weight storage
(actually, it might be 2/3, but we'll stick with 1/3), and a conservative figure
of 3.2 transistors per gate (very conservative if you'll be latching a lot of
the values), this leaves 500000 gates. With 64 gates per bitboard for a simple
XOR, for example, it seems there must be a limit to the complexity of the
evaluation in the chip, given 8000 features in the evaluation. Since I don't do
hardware design, I realize my figures may be wrong, but if so can you please
explain. 8000 features * 64 bits = 512000 gates for a simple function, so does
that rule out the possibility that they are using bitboards?


kp



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