Re: Question on Non-simulability

[John M <***>]

Dear Howard,
thanks for the explanation, I did not understand one word of it.
My mistake.
Q: Does  "An analog computer uses ..." mean that there IS such a thing? As
your concluding sentence said: "...the design of the analog is limited only
by your imagination."
Is that example (simulating?) the pendulum not an old fashioned "physical
modeling"?
Regaards
John M

----- Original Message -----
From: "Howard Pattee" <***>
To: <***>
Sent: Saturday, August 21, 2004 8:25 PM
Subject: Re: Question on Non-simulability


> John asked:
> Could you tell more about that "analog device"? i searched for the "analog
> comput/er/ing" and asked lots of people - no dice.
>
> HP: An analog computer uses continuous physical variables such as a
voltage in a circuit to model some other physical variable or behavior.
Rosen's favorite simple example is the voltage in a tuned
inductive/capacitive circuit that models the displacement of a simple
pendulum. These are generally dynamical systems, so they operate in real
time.
>
> There is no formal definition of analog computers, like Turing
equivalence, because the design of the analog is limited only by your
imagination.
>
> Howard