Personal and Historical Perspectives of Hans Bethe. Inside-out_torus_(animated,_small).gif (GIF Image, 170x170 pixels) Langtons Ant -- from Wolfram MathWorld. A 4-state two-dimensional Turing machine invented in the 1980s. The ant starts out on a grid containing black and white cells, and then follows the following set of rules. 1.
If the ant is on a black square, it turns right and moves forward one unit. 2. 3. When the ant is started on an empty grid, it eventually builds a "highway" that is a series of 104 steps that repeat indefinitely, each time displacing the ant two pixels vertically and horizontally. (right figure) steps. Universal Turing machine. In computer science, a universal Turing machine (UTM) is a Turing machine that can simulate an arbitrary Turing machine on arbitrary input. The universal machine essentially achieves this by reading both the description of the machine to be simulated as well as the input thereof from its own tape. Alan Turing introduced this machine in 1936–1937. This model is considered by some (for example, Martin Davis (2000)) to be the origin of the stored program computer—used by John von Neumann (1946) for the "Electronic Computing Instrument" that now bears von Neumann's name: the von Neumann architecture.
It is also known as universal computing machine, universal machine (UM), machine U, U. In terms of computational complexity, a multi-tape universal Turing machine need only be slower by logarithmic factor compared to the machines it simulates. Introduction[edit] Every Turing machine computes a certain fixed partial computable function from the input strings over its alphabet. Efficiency[edit] Turing machine. An artistic representation of a Turing machine (Rules table not represented) A Turing machine is a hypothetical device that manipulates symbols on a strip of tape according to a table of rules.
Despite its simplicity, a Turing machine can be adapted to simulate the logic of any computer algorithm, and is particularly useful in explaining the functions of a CPU inside a computer. The "Turing" machine was invented in 1936 by Alan Turing[1] who called it an "a-machine" (automatic machine). The Turing machine is not intended as practical computing technology, but rather as a hypothetical device representing a computing machine. Turing machines help computer scientists understand the limits of mechanical computation. Turing gave a succinct definition of the experiment in his 1948 essay, "Intelligent Machinery". ...an unlimited memory capacity obtained in the form of an infinite tape marked out into squares, on each of which a symbol could be printed.
Informal description[edit] where to.