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Variable Word Length Computers
Variable may refer to: Computer science * Variable (computer science), a symbolic name associated with a value and whose associated value may be changed Mathematics * Variable (mathematics), a symbol that represents a quantity in a mathematical expression, as used in many sciences * Propositional variable, taking the value true or false in mathematical logic * Random variable, a variable in statistics whose value depends on random events ** Categorical variable, taking one of a finite number of values in a statistical problem, such as the head or tail result of a tossed coin ** Independent and identically distributed random variables, statistically independent and having the same probability distribution * Fluent (mathematics), a time-varying quantity as coined by Isaac Newton in his early calculus * State variable, used to describe the mathematical "state" of a dynamical system * Slack variable, inserted to transform an inequality constraint in an optimization problem into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable (computer Science)
In computer programming, a variable is an abstract storage location paired with an associated symbolic name, which contains some known or unknown quantity of data or object referred to as a '' value''; or in simpler terms, a variable is a named container for a particular set of bits or type of data (like integer, float, string, etc...). A variable can eventually be associated with or identified by a memory address. The variable name is the usual way to reference the stored value, in addition to referring to the variable itself, depending on the context. This separation of name and content allows the name to be used independently of the exact information it represents. The identifier in computer source code can be bound to a value during run time, and the value of the variable may thus change during the course of program execution. Variables in programming may not directly correspond to the concept of variables in mathematics. The latter is abstract, having no reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Variables And Bound Variables
In mathematics, and in other disciplines involving formal languages, including mathematical logic and computer science, a variable may be said to be either free or bound. Some older books use the terms real variable and apparent variable for free variable and bound variable, respectively. A ''free variable'' is a Mathematical notation, notation (symbol) that specifies places in an expression (mathematics), expression where Substitution (logic), substitution may take place and is not a parameter of this or any container expression. The idea is related to a ''placeholder'' (a symbol that will later be replaced by some value), or a wildcard character that stands for an unspecified symbol. In computer programming, the term free variable refers to variable (programming), variables used in a function (computer science), function that are neither local variables nor parameter (computer programming), parameters of that function. The term non-local variable is often a synonym in this co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Variable (other)
Hidden variable may refer to: * Confounding, in statistics, an extraneous variable in a statistical model that correlates (directly or inversely) with both the dependent variable and the independent variable * Hidden transformation, in computer science, a way to transform a generic constraint satisfaction problem into a binary one by introducing new hidden variables * Hidden-variable theory, in physics, the proposition that statistical models of physical systems (such as Quantum mechanics) are inherently incomplete, and that the apparent unpredictability of such systems is actually due to the influence of additional, putative yet-unseen or unmeasurable factors ** Local hidden-variable theory, in quantum mechanics, a hidden-variable theory in which distant events are assumed to have no instantaneous (or at least faster-than-light) effect on local events * Latent variable In statistics, latent variables (from Latin: present participle of ) are variables that can only be inferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lost (2004 TV Series)
''Lost'' is an American science fiction on television, science fiction Adventure fiction, adventure Drama (film and television), drama television series created by Jeffrey Lieber, J. J. Abrams, and Damon Lindelof that aired on American Broadcasting Company, ABC from September 22, 2004, to May 23, 2010, with a total of List of Lost episodes, 121 episodes over six seasons. It contains elements of supernatural fiction and follows the survivors of a commercial jet airliner flying between Sydney and Los Angeles after the plane crashes on a mysterious Mythology of Lost#The Island, island somewhere in the South Pacific Ocean. Episodes typically feature a primary storyline set on the island, augmented by flashback (narrative), flashback or flashforward sequences which provide additional insight into the involved characters. Lindelof and Carlton Cuse served as showrunners and were executive producers along with Abrams and Bryan Burk. Inspired by the 2000 film ''Cast Away'', the show is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Variable
"The Variable" is the 14th television episode of the fifth season of '' Lost'', and the 100th episode overall. It originally aired on the American Broadcasting Company (ABC) in the United States on April 29, 2009. The hundredth episode milestone was celebrated by cast and crew on location in Hawaii. In the episode, Daniel Faraday ( Jeremy Davies) returns to the Island in order to warn the inhabitants of a catastrophe involving the DHARMA Initiative research station the Swan. Jack (Matthew Fox), Kate ( Evangeline Lilly) and Daniel begin a fight with DHARMA, leading DHARMA to go after Sawyer (Josh Holloway) and Juliet (Elizabeth Mitchell). In flashbacks, Daniel's relationship with his parents, Eloise Hawking ( Fionnula Flanagan) and Charles Widmore (Alan Dale), is shown. The episode was written by executive producers Edward Kitsis and Adam Horowitz and directed by Paul Edwards. It serves as a companion piece to the season four episode " The Constant", another episode th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * ''Intrinsic variables'', whose luminosity actually changes periodically; for example, because the star swells and shrinks. * ''Extrinsic variables'', whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it. Many, possibly most, stars exhibit at least some oscillation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsing binary Algol. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Variable
A control variable (or scientific constant) in scientific experimentation is an experimental element which is constant (controlled) and unchanged throughout the course of the investigation. Control variables could strongly influence experimental results were they not held constant during the experiment in order to test the relative relationship of the dependent variable (DV) and independent variable (IV). The control variables themselves are not of primary interest to the experimenter. "Good controls", also known as “confounders” or “deconfounders”, are variables which are theorized to be unaffected by the treatment and which are intended to eliminate omitted-variable bias. "Bad controls", on the other hand, are variables that could be affected by the treatment, might contribute to collider bias, and lead to erroneous results. Usage A variable in an experiment which is held constant in order to assess the relationship between multiple variables, is a control variable. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable (research)
In science and research, an attribute is a quality of an object (person, thing, etc.). Earl R. Babbie, ''The Practice of Social Research'', 12th edition, Wadsworth Publishing, 2009, , p. 14-18 Attributes are closely related to variables. A variable is a logical set of attributes. Variables can "vary" – for example, be high or low. How high, or how low, is determined by the value of the attribute (and in fact, an attribute could be just the word "low" or "high"). ''(For example see: Binary option)'' While an attribute is often intuitive, the variable is the operationalized way in which the attribute is represented for further data processing. In data processing data are often represented by a combination of ''items'' (objects organized in rows), and multiple variables (organized in columns). Values of each variable statistically "vary" (or are distributed) across the variable's domain. A domain is a set of all possible values that a variable is allowed to have. The values are o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complex Analysis
Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebraic geometry, number theory, analytic combinatorics, and applied mathematics, as well as in physics, including the branches of hydrodynamics, thermodynamics, quantum mechanics, and twistor theory. By extension, use of complex analysis also has applications in engineering fields such as nuclear, aerospace, mechanical and electrical engineering. As a differentiable function of a complex variable is equal to the sum function given by its Taylor series (that is, it is analytic), complex analysis is particularly concerned with analytic functions of a complex variable, that is, '' holomorphic functions''. The concept can be extended to functions of several complex variables. Complex analysis is contrasted with real analysis, which dea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependent And Independent Variables
A variable is considered dependent if it depends on (or is hypothesized to depend on) an independent variable. Dependent variables are studied under the supposition or demand that they depend, by some law or rule (e.g., by a mathematical function), on the values of other variables. Independent variables, on the other hand, are not seen as depending on any other variable in the scope of the experiment in question. Rather, they are controlled by the experimenter. In pure mathematics In mathematics, a function (mathematics), function is a rule for taking an input (in the simplest case, a number or set of numbers)Carlson, Robert. A concrete introduction to real analysis. CRC Press, 2006. p.183 and providing an output (which may also be a number). A symbol that stands for an arbitrary input is called an independent variable, while a symbol that stands for an arbitrary output is called a dependent variable. The most common symbol for the input is , and the most common symbol for the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable (mathematics)
In mathematics, a variable (from Latin language, Latin ) is a Mathematical symbol, symbol, typically a letter, that refers to an unspecified mathematical object. One says colloquially that the variable ''represents'' or ''denotes'' the object, and that any valid candidate for the object is the value (mathematics), value of the variable. The values a variable can take are usually of the same kind, often numbers. More specifically, the values involved may form a Set (mathematics), set, such as the set of real numbers. The object may not always exist, or it might be uncertain whether any valid candidate exists or not. For example, one could represent two integers by the variables and and require that the value of the square of is twice the square of , which in algebraic notation can be written . A definitive proof that this relationship is impossible to satisfy when and are restricted to integer numbers isn't obvious, but it has been known since ancient times and has had a big ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slack Variable
In an optimization problem, a slack variable is a variable that is added to an inequality constraint to transform it into an equality constraint. A non-negativity constraint on the slack variable is also added. Slack variables are used in particular in linear programming. As with the other variables in the augmented constraints, the slack variable cannot take on negative values, as the simplex algorithm requires them to be positive or zero. * If a slack variable associated with a constraint is ''zero'' at a particular candidate solution, the constraint is binding there, as the constraint restricts the possible changes from that point. * If a slack variable is ''positive'' at a particular candidate solution, the constraint is non-binding there, as the constraint does not restrict the possible changes from that point. * If a slack variable is ''negative'' at some point, the point is infeasible (not allowed), as it does not satisfy the constraint. Slack variables are also used i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
