Glossary

This glossary includes a compilation of terms specific to Analytica as well as statistical terms used in this manual.

Array: A collection of values that can be viewed as one or more tables. An array has one or more dimen- sions; each dimension is identified by an index.

Arrow, influence arrow: Influence arrows (or arrows) from one variable node to another indicate that the origin node affects (influences) the destination node. If the nodes depict variables, the origin variable is an input to the destination variable, and the destination variable is an output of the origin variable.

Attribute: A property of an object, such as its title, description, definition, value, or inputs.

Attribute panel: An auxiliary window pane that can open below an influence diagram. Use it to rapidly examine one attribute at a time of any variable, function, or module.

Browse tool: A tool for examining the structure and assumptions of a model, with limited ability to make changes to the model.

Chance variable: An uncertain variable that cannot be directly controlled by the decision maker. It is usually defined by a probability distribution. A chance variable is represented by an oval node.

Class: Analytica objects are organized into the following classes: module, attribute, function, and decision, chance, objective, index, and general variables.

Cumulative probability distribution: A graphical representation of a probability distribution. It plots the cumulative probability that the actual value of the uncertain variable X is less than or equal to each possible value of X. The cumulative probability distribution is a display option in the Uncertainty View popup menu in a Result window.

Decision variable: A variable that the decision maker can control directly. A decision variable is represented by a rectangular node.

Definition: A specification for computing a variable’s value. The definition can be a number, a mathematical expression, a list of values, a table, or a probability distribution.

Description: Text explaining what the object represents in the system being modeled. The description is lim- ited to 32,000 characters in length.

Deterministic table: A function that gives the value of a variable conditional on the values of its input variables, where the inputs are all discrete variables.

Domain: The possible outcomes for a variable defined as a probability table.

Edit table: A definition that is an array (table) is also called an edit table because it can be edited.

Edit tool: A tool for creating or changing a model. Use it to move, resize, and edit nodes, and to expose the arrow tool and node palette.

Expression: A formula that can contain any combination of numbers, variables, functions, distributions, and operators, such as 0.5, a-b, or Min(x), combined according to the Analytica language syntax. Expression type Expression types include expression, list (of expressions or numbers), list of labels (text strings), table, probability table, and distribution. You select an expression type using the Expression popup menu, which appears above the Definition field. Note that any definition, regardless of expression type, can be viewed as an expression.

General variable: Any type of variable; useful when the variable type is unknown. The general variable typically rep- resents a deterministic or functional dependency.

Graph: Format for displaying a multidimensional result. To view a result as a graph, click the Graph but- ton. See also Table.

Identifier: A short name for an object. A variable’s identifier is used to refer to the variable in mathematical expressions in definitions of other variables. An identifier must start with a letter, have no more than 20 characters, and contain only letters, numbers, and the underscore character (_) (used instead of a space). Compare to Title.

See Also