On Sat, 16 Sep 2017 12:04:27 +1200, Michael Cree wrote:
On Fri, Sep 15, 2017 at 10:34:14PM +1200, Lawrence D'Oliveiro wrote:
The essence of analog computing is that physical quantities are represented by physical quantities.
Huh? I'm not sure what you are trying to say here as what you state is just a tautology.
It’s the difference between analog and digital computers: in an analog computer, a scalar physical quantity in the model being solved is represented by a scalar physical quantity in the machine. In a digital computer, each scalar physical quantity in the machine is just a digit of a number (hence “digital”); you usually have several of these to represent a single quantity in the model, using a place-system encoding, also exponents etc. Thus, physical limitations in the construction of digital machines don’t constrain the accuracy with which we can do calculations, only their speed; whereas in analog machines their accuracy is constrained as well.