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What does this mean??

 
 
Thomas G. Marshall
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      11-06-2005
zero coughed up:
> "Thomas G. Marshall"
> <(E-Mail Removed). com> wrote in
> news:i0qbf.4532$41.2418@trndny04:
>
>>
>> You remember wrong.
>>
>> When I went to school for computer science we had to take a
>> substantial amount of electrical engineering. The courseload for the
>> class just beyond our required classes had the engineers building a 32
>> bit multiplier out of ttl hardware. The algorithm for n bits * n bits
>> is of order n*n. O(n*n).
>>
>> I've also implemented 32 and 64 bit multiplication algorithms on 8 bit
>> machines that had no such concept. You just don't do it by successive
>> additions, because you don't have to.
>>
>> Can you imagine the multiplication of two large numbers? It could
>> possibly take a /very/ long time by cpu standards. They would never
>> be able to manage it in the handful of cycles that they do. 64 bits
>> could handle 2 32bit numbers multiplied. That would be an iteration
>> of 4 billion in microcode or other chipset hardware!!!!!!
>>
>> Read the section under "Long Multiplication".
>>
>> http://www.answers.com/topic/multiplication-algorithm
>>
>>

>
> Ok I yield. You're right, I'm wrong.


No, no. Say it again! Say it again!

Yield again dammit!

LOL. Seriously though, I'm sorry for being AR.


--
Enough is enough. It is /not/ a requirement that someone must google
relentlessly for an answer before posting in usenet. Newsgroups are for
discussions. Discussions do /not/ necessitate prior research. If you are
bothered by someone asking a question without taking time to look something
up, simply do not respond.


 
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Roedy Green
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      11-06-2005
On Sun, 06 Nov 2005 16:17:18 GMT, "Thomas G. Marshall"
<(E-Mail Removed). com> wrote, quoted
or indirectly quoted someone who said :

>Can you imagine the multiplication of two large numbers? It could possibly
>take a /very/ long time by cpu standards. They would never be able to
>manage it in the handful of cycles that they do. 64 bits could handle 2
>32bit numbers multiplied. That would be an iteration of 4 billion in
>microcode or other chipset hardware!!!!!!


Yes and an ordinary 32x32 bit multiply is done in hardware with
parallel shifts and parallel adds, is it not? These fancy algorithms
such as karatsuba only apply for large BigInteger calculations.
--
Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.
 
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Roedy Green
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      11-06-2005
On Sun, 06 Nov 2005 16:17:18 GMT, "Thomas G. Marshall"
<(E-Mail Removed). com> wrote, quoted
or indirectly quoted someone who said :

>
>He said a loop using *only addition*.


He said that but he also said loop which implies some extra minor
stuff. The extra minor stuff he forgot about is the shift and test.

The point I am making is the source he originally heard this from was
likely correct. It is just he did not remember the WHOLE story. He
just remembered that part of the algorithm was a mess of additions.

His error would be akin to forgetting to shift over one for each line
when doing manual decimal multiply.
--
Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.
 
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Thomas G. Marshall
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      11-07-2005
Roedy Green coughed up:
> On Sun, 06 Nov 2005 16:17:18 GMT, "Thomas G. Marshall"
> <(E-Mail Removed). com> wrote, quoted
> or indirectly quoted someone who said :
>
>>
>> He said a loop using *only addition*.

>
> He said that but he also said loop which implies some extra minor
> stuff. The extra minor stuff he forgot about is the shift and test.



That's hardly "some minor stuff". That shift and test are the small binary
multiplies that are critical parts of the algorithm! That's like saying
that a sort routine is a comparison plus some minor stuff.

His notion was that it was merely cyclical addition. What he remembers,
from whom, and why, are of no consequence or value, much like our
conversation here.

I'm done with this diversion.


--
It's time for everyone to just step back, take a deep breath, relax, and
stop
throwing hissy fits over crossposting.


 
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