 Computation

Computation is defined as any type of calculation.^{[1]} Also defined as use of computer technology in Information processing.^{[2]}^{[3]}Computation is a process following a welldefined model understood and expressed in an algorithm, protocol, network topology, etc. Computation is also a major subject matter of computer science: it investigates what can or cannot be done in a computational manner.
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Classes of computation
Computation can be classified by at least three orthogonal criteria: digital vs analog, sequential vs parallel vs concurrent, batch vs interactive.
In practice, digital computation is often used to simulate natural processes (for example, Evolutionary computation), including those that are more naturally described by analog models of computation (for example, Artificial neural network).
Computations as a physical phenomenon
A computation can be seen as a purely physical phenomenon occurring inside a closed physical system called a computer. Examples of such physical systems include digital computers, mechanical computers, quantum computers, DNA computers, molecular computers, analog computers or wetware computers. This point of view is the one adopted by the branch of theoretical physics called the physics of computation.
An even more radical point of view is the postulate of digital physics that the evolution of the universe itself is a computation  Pancomputationalism.
Mathematical models of computation
In the theory of computation, a diversity of mathematical models of computers have been developed. Typical mathematical models of computers are the following:
 State models including Turing Machine, pushdown automaton, finite state automaton, and PRAM
 Functional models including lambda calculus
 Logical models including logic programming
 Concurrent models including actor model and process calculi
History
The word computation has an archaic meaning (from its Latin etymological roots), but the word has come back in use with the arising of a new scientific discipline: computer science.
Comparison to calculation
See also
 Computing
 Physical information
 Real computation
 Reversible computation
 Hypercomputation
References
Categories: Theoretical computer science
 Computability theory
 Computer science stubs
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