Options
=======

*Options* (also called *alternatives*) are basic entities studied in a
:doc:`decision problem <DEXiGlosDProb>`. Depending on the problem, they
can represent different objects, solutions, courses of action, etc.,
which are :doc:`evaluated <DEXiGlosEval>` and
:doc:`analyzed <DEXiGlosAnal>` by a :doc:`multi-attribute
model <DEXiGlosMAMod>`.

In :doc:`DEXi <DEXi>`, each option is represented by its *name* (not
necessarily unique) and a set of *values*, so that one value is assigned
to each :doc:`attribute <DEXiGlosAttr>` in the :doc:`tree of
attributes <DEXiGlosTree>`. These values are further distinguished
into:

-  *option description*: vector of values assigned to basic attributes;
-  *intermediate evaluation results*: values assigned to aggregate
   attributes other than the roots of the tree;
-  *final* (or *overall*) *evaluation results*: values assigned to the
   root(s) of the tree.

Values assigned to basic attributes can be either defined or undefined:

-  *Defined* means that a single qualitative value from the
   corresponding :doc:`scale <DEXiGlosScale>` has been assigned to that
   attribute.
-  *Undefined* means that the value is unknown or unspecified. In DEXi,
   this is denoted by an asterisk '\*' and is interpreted as a *set of
   all values* that can be assigned to the corresponding attribute.

Example
-------

See :doc:`options (cars) <DEXiCarEval>` as described and
:doc:`evaluated <DEXiGlosEval>` in the :doc:`Car Evaluation <DEXiCar>`
model.

See also
--------

DEXi's :doc:`Options Page <DEXiIntTabOpt>`.

DEXi's :doc:`Evaluation Page <DEXiIntTabEval>`.

Saving options on :doc:`files <DEXiIntOptFile>`.

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