On 12/13/2018 4:15 AM, Bruno Marchal wrote:
See the bit about reversible computing:
https://en.wikipedia.org/wiki/Landauer%27s_principle (computations
that are reversible require no energy).
And they produce no results since they run both ways. They are not
even computations in the CT sense.
They are computations in the CT sense.
CT computations halt. A program that can just wander back an forth
at random doesn't halt.
?
There is no CT for the programs who always halt. Universal machine
would not exist. The price of being a universal machine is that not
only it does not always halt, but there is no mechanical procedure
deciding when it halts or not.
No, my point was that unless a program halts it has not computed
anything. I objected to the above /"computations that are reversible
require no energy"/. This is either a statement about the abstract
mathematical computation, in which case it is trivial, or it is a
statement about physically realized computations in which case it is
false because physically reversible computations have no direction.
Brent
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
