On Apr 27, 8:55 pm, rjf <fate...@gmail.com> wrote:
> Oh, just another note.
>
> There are people who have made their whole careers on devising
> asymptotically fast algorithms
> which have never been implemented, or (if they have been implemented)
> are not fast because
> their overly-simplified analysis does not fit the currently available
> computer efficiency profile.
> Indeed, their analysis may not fit any past profile of computers, and
> their algorithms were never
> practical.

Interesting observation. Furer's algorithm is not practical, as are
some matrix multiplication algorithms. Do you have any other examples
in mind?

>
> Note, for example, that memory access is far more expensive than
> arithmetic, and that
> many computers now can multiply or add in comparable time; and they
> have several multipliers. Etc.

I would say that memory access if far more expensive than addition,
but not arithmetic in general. FFT multiplication is n log n
(sometimes with a log log n, depending on what you are multiplying)
and I would say the memory access perhaps adds a hidden log n factor.

Can you perhaps be more specific as to what you are hinting at?

>
> RJF
>
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