Entropy vs Nat - What's the difference?
As nouns the difference between entropy and nat
is that entropy
is (thermodynamics|countable) while nat
is a spirit in burmese mythology, whose cult is followed alongside buddhism or nat
can be logarithmic unit of information or entropy, based on natural logarithms.
As a adverb nat is
# strictly thermodynamic entropy . A measure of the amount of energy in a physical system that cannot be used to do work.
# A measure of the disorder present in a system.
- The thermodynamic free energy is the amount of work that a thermodynamic system can perform; it is the internal energy of a system minus the amount of energy that cannot be used to perform work. That unusable energy is given by the entropy''' of a system multiplied by the temperature of the system.''[http://en.wikipedia.org/wiki/Thermodynamic_free_energy] ''(Note that, for both Gibbs and Helmholtz free energies, temperature is assumed to be fixed, so '''entropy is effectively directly proportional to useless energy.)
# The capacity factor for thermal energy that is hidden with respect to temperature [http://arxiv.org/pdf/physics/0004055].
# The dispersal of energy; how much energy is spread out in a process, or how widely spread out it becomes, at a specific temperature. [http://www.entropysite.com/students_approach.html]
(statistics, information theory, countable) A measure of the amount of information and noise present in a signal. Originally a tongue-in-cheek coinage, has fallen into disuse to avoid confusion with thermodynamic entropy.
(uncountable) The tendency of a system that is left to itself to descend into chaos.
- Ludwig Boltzmann defined entropy''' as being directly proportional to the natural logarithm of the number of microstates yielding an equivalent thermodynamic macrostate (with the eponymous constant of proportionality). Assuming (by the fundamental postulate of statistical mechanics), that all microstates are equally probable, this means, on the one hand, that macrostates with higher '''entropy''' are more probable, and on the other hand, that for such macrostates, the quantity of information required to describe a particular one of its microstates will be higher. That is, the Shannon '''entropy''' of a macrostate would be directly proportional to the logarithm of the number of equivalent microstates (making it up). In other words, thermodynamic and informational entropies are rather compatible, which shouldn't be surprising since Claude Shannon derived the notation 'H' for information '''entropy from Boltzmann's H-theorem.
* bound entropy
* free entropy
* algorithmic entropy
* conditional entropy
* information entropy
* joint entropy
* Shannon entropy
* von Neumann entropy
(Internet) A network function whereby one network address is rewritten (translated) to another address: Network Address Translation is frequently used to allow multiple network nodes (computers or inter-networked devices) to share a single internet (or local network) IP address. NAT may be used in "one to one", "many to one", or "one to many" types of configurations.
(Internet) A device that implements that network function; a NAT firewall.