Computation
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Computation is any type of calculation[1] or use of computing technology in information processing.[2][3] Computation is a process following a well-defined model understood and expressed as, for example, an algorithm, or a protocol.
The study of computation is paramount to the discipline of computer science.
Classification
Computation can be classified by at least three orthogonal criteria: digital versus analog, sequential versus parallel versus concurrent, batch versus 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).
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
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, push-down 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.