Wireworld

Last updated
2 Wireworld diodes, the above one in conduction direction, the lower one in reverse-biasing Wireworld two-diodes.gif
2 Wireworld diodes, the above one in conduction direction, the lower one in reverse-biasing

Wireworld, alternatively WireWorld, is a cellular automaton first proposed by Brian Silverman in 1987, as part of his program Phantom Fish Tank. It subsequently became more widely known as a result of an article in the "Computer Recreations" column of Scientific American . [1] Wireworld is particularly suited to simulating transistors, and is Turing-complete.

Contents

Rules

Example of a complicated circuit made in WireWorld: a seven-segment display and decoder. Conductor cells are dark green to highlight signal flow and display segments. Animated display.gif
Example of a complicated circuit made in WireWorld: a seven-segment display and decoder. Conductor cells are dark green to highlight signal flow and display segments.

A Wireworld cell can be in one of four different states, usually numbered 03 in software, modeled by colors in the examples here:

  1. empty (black),
  2. electron head (blue),
  3. electron tail (red),
  4. conductor (yellow).

As in all cellular automata, time proceeds in discrete steps called generations (sometimes "gens" or "ticks"). Cells behave as follows:

Wireworld uses what is called the Moore neighborhood, which means that in the rules above, neighbouring means one cell away (range value of one) in any direction, both orthogonal and diagonal.

These simple rules can be used to construct logic gates (see below).

2 clock generators sending electrons into an XOR gate Wireworld XOR-gate.gif
2 clock generators sending electrons into an XOR gate

Applications

Entities built within Wireworld universes include Langton's ant (allowing any Langton's ant pattern to be built within Wireworld) [2] and the Wireworld computer, a Turing-complete computer implemented as a cellular automaton. [3]

See also

Related Research Articles

<span class="mw-page-title-main">Conway's Game of Life</span> Two-dimensional cellular automaton

The Game of Life, also known as Conway's Game of Life or simply Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further input. One interacts with the Game of Life by creating an initial configuration and observing how it evolves. It is Turing complete and can simulate a universal constructor or any other Turing machine.

<span class="mw-page-title-main">Cellular automaton</span> Discrete model studied in computer science

A cellular automaton is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessellation structures, and iterative arrays. Cellular automata have found application in various areas, including physics, theoretical biology and microstructure modeling.

<i>A New Kind of Science</i> Book by Stephen Wolfram

A New Kind of Science is a book by Stephen Wolfram, published by his company Wolfram Research under the imprint Wolfram Media in 2002. It contains an empirical and systematic study of computational systems such as cellular automata. Wolfram calls these systems simple programs and argues that the scientific philosophy and methods appropriate for the study of simple programs are relevant to other fields of science.

<span class="mw-page-title-main">Langton's ant</span> Two-dimensional Turing machine with emergent behavior

Langton's ant is a two-dimensional Turing machine with a very simple set of rules but complex emergent behavior. It was invented by Chris Langton in 1986 and runs on a square lattice of black and white cells. The idea has been generalized in several different ways, such as turmites which add more colors and more states.

<span class="mw-page-title-main">Rule 110</span> Elementary cellular automaton

The Rule 110 cellular automaton is an elementary cellular automaton with interesting behavior on the boundary between stability and chaos. In this respect, it is similar to Conway's Game of Life. Like Life, Rule 110 with a particular repeating background pattern is known to be Turing complete. This implies that, in principle, any calculation or computer program can be simulated using this automaton.

A cellular automaton (CA) is Life-like if it meets the following criteria:

<span class="mw-page-title-main">Garden of Eden (cellular automaton)</span> Pattern that has no predecessors

In a cellular automaton, a Garden of Eden is a configuration that has no predecessor. It can be the initial configuration of the automaton but cannot arise in any other way. John Tukey named these configurations after the Garden of Eden in Abrahamic religions, which was created out of nowhere.

<span class="mw-page-title-main">Turmite</span> Turing machine on a two-dimensional grid

In computer science, a turmite is a Turing machine which has an orientation in addition to a current state and a "tape" that consists of an infinite two-dimensional grid of cells. The terms ant and vant are also used. Langton's ant is a well-known type of turmite defined on the cells of a square grid. Paterson's worms are a type of turmite defined on the edges of an isometric grid.

<span class="mw-page-title-main">Codd's cellular automaton</span> 2D cellular automaton devised by Edgar F. Codd in 1968

Codd's cellular automaton is a cellular automaton (CA) devised by the British computer scientist Edgar F. Codd in 1968. It was designed to recreate the computation- and construction-universality of von Neumann's CA but with fewer states: 8 instead of 29. Codd showed that it was possible to make a self-reproducing machine in his CA, in a similar way to von Neumann's universal constructor, but never gave a complete implementation.

<span class="mw-page-title-main">Cyclic cellular automaton</span>

A cyclic cellular automaton is a kind of cellular automaton rule developed by David Griffeath and studied by several other cellular automaton researchers. In this system, each cell remains unchanged until some neighboring cell has a modular value exactly one unit larger than that of the cell itself, at which point it copies its neighbor's value. One-dimensional cyclic cellular automata can be interpreted as systems of interacting particles, while cyclic cellular automata in higher dimensions exhibit complex spiraling behavior.

<span class="mw-page-title-main">Billiard-ball computer</span> Type of conservative logic circuit

A billiard-ball computer, a type of conservative logic circuit, is an idealized model of a reversible mechanical computer based on Newtonian dynamics, proposed in 1982 by Edward Fredkin and Tommaso Toffoli. Instead of using electronic signals like a conventional computer, it relies on the motion of spherical billiard balls in a friction-free environment made of buffers against which the balls bounce perfectly. It was devised to investigate the relation between computation and reversible processes in physics.

<span class="mw-page-title-main">Langton's loops</span> Self-reproducing cellular automaton patterns

Langton's loops are a particular "species" of artificial life in a cellular automaton created in 1984 by Christopher Langton. They consist of a loop of cells containing genetic information, which flows continuously around the loop and out along an "arm", which will become the daughter loop. The "genes" instruct it to make three left turns, completing the loop, which then disconnects from its parent.

Humans have considered and tried to create non-biological life for at least 3,000 years. As seen in tales ranging from Pygmalion to Frankenstein, humanity has long been intrigued by the concept of artificial life.

Quantum dot cellular automata are a proposed improvement on conventional computer design (CMOS), which have been devised in analogy to conventional models of cellular automata introduced by John von Neumann.

<span class="mw-page-title-main">Von Neumann universal constructor</span> Self-replicating cellular automaton

John von Neumann's universal constructor is a self-replicating machine in a cellular automaton (CA) environment. It was designed in the 1940s, without the use of a computer. The fundamental details of the machine were published in von Neumann's book Theory of Self-Reproducing Automata, completed in 1966 by Arthur W. Burks after von Neumann's death. It is regarded as foundational for automata theory, complex systems, and artificial life. Indeed, Nobel Laureate Sydney Brenner considered Von Neumann's work on self-reproducing automata central to biological theory as well, allowing us to "discipline our thoughts about machines, both natural and artificial."

A quantum cellular automaton (QCA) is an abstract model of quantum computation, devised in analogy to conventional models of cellular automata introduced by John von Neumann. The same name may also refer to quantum dot cellular automata, which are a proposed physical implementation of "classical" cellular automata by exploiting quantum mechanical phenomena. QCA have attracted a lot of attention as a result of its extremely small feature size and its ultra-low power consumption, making it one candidate for replacing CMOS technology.

<span class="mw-page-title-main">Rule 90</span> Elementary cellular automaton

In the mathematical study of cellular automata, Rule 90 is an elementary cellular automaton based on the exclusive or function. It consists of a one-dimensional array of cells, each of which can hold either a 0 or a 1 value. In each time step all values are simultaneously replaced by the XOR of their two neighboring values. Martin, Odlyzko & Wolfram (1984) call it "the simplest non-trivial cellular automaton", and it is described extensively in Stephen Wolfram's 2002 book A New Kind of Science.

Mobile automaton within theoretical computer science, is a class of automata similar to cellular automata but which have a single "active" cell instead of updating all cells in parallel. In a mobile automaton, the evolution rules apply only to the active cell, and also specify how the active cell moves from one generation to the next. All cells that are not active remain the same from one generation to the next. Mobile automata can therefore be considered a hybrid between elementary cellular automata and Turing machines.

<span class="mw-page-title-main">Byl's loop</span> Cellular automaton

The Byl's loop is an artificial lifeform similar in concept to Langton's loop. It is a two-dimensional, 5-neighbor cellular automaton with 6 states per cell, and was developed in 1989 by John Byl, from the Department of Mathematical Sciences of Trinity Western University.

<span class="mw-page-title-main">Reversible cellular automaton</span> Cellular automaton that can be run backwards

A reversible cellular automaton is a cellular automaton in which every configuration has a unique predecessor. That is, it is a regular grid of cells, each containing a state drawn from a finite set of states, with a rule for updating all cells simultaneously based on the states of their neighbors, such that the previous state of any cell before an update can be determined uniquely from the updated states of all the cells. The time-reversed dynamics of a reversible cellular automaton can always be described by another cellular automaton rule, possibly on a much larger neighborhood.

References

  1. Dewdney, A K (January 1990). "Computer recreations: The cellular automata programs that create Wireworld, Rugworld and other diversions". Scientific American . 262 (1): 146–149. doi:10.1038/scientificamerican0190-146. JSTOR   24996654 . Retrieved 2 December 2018.
  2. Nyles Heise. "Wireworld". Archived from the original on 2011-02-04.
  3. Mark Owen. "The Wireworld Computer".