🚀 go-pugleaf

radford@cs.toronto.edu (Radford Neal) writes:

>Go right ahead and adopt this Turing machine for all your computing
>needs if it makes you happy, but I suspect you'll find it a bit slow
>and awkward, as well as difficult to get good repair service for.

You misunderstand completely.
Just beacause you define a unit of time in terms of
the spectral frequency of caesium,
that does not mean that every wristwatch
has to include a caesium laser.

>As for myself, I'm happy to use whatever machine seems convenient at
>the time. In particular, if I'm interested in storing images compactly
>for later display, I'm happy to use a "machine" that is carefully
>tailored so that there are short "programs" that produce images that
>crop up a lot, at the expense of long "programs" for images that don't
>occur very often.

You will find that in order to separate your "easy" images
you will need rather a lot of cyles on the universal Turing machine U.

>What is it about data compression that induces so much confusion in
>the layperson? 

Which category do you place yourself in?
Since you base your comments on my posting,
which referred explicitly and exclusively
to Chaitin/Kolmogorov Algorithmic Information Theory,
may I ask if you have read anything on this subject?

>Half of them seem to think it plausible that one
>could compress any data set into practically nothing without any
>knowledge of the source probabilities, while the other half think 
>that knowledge of the source is irrelevant in light of mythical
>"theoretical limits" . . .

They are not mythical.
It is you who confuse theoretical and practical matters.
You dismissed my theoretical definition of informational content
(or entropy)
on the grounds that it was not based on practical computing practice.
This is like dismissing the special theory of relativity
on the grounds that Einstein
did not try to drive faster than the speed of light.

-- 
Timothy Murphy  
e-mail: tim@maths.tcd.ie
tel: +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland