.. _DexAlternative:

Alternatives
------------

*Alternatives*  are basic entities studied in a :ref:`decision problem <MethDecisionProblem>`.
Depending on the problem, they can represent different objects, solutions, courses of action, etc.,
which are :ref:`evaluated <DexEvaluation>` and
:ref:`analyzed <DexAnalysis>` by a :ref:`DEX model <DexModel>`.

In `DEXi Suite <https://dex.ijs.si/documentation/DEX_Software/DEXiSuite.html>`__,
each alternative is represented by its:

- *name* (not necessarily unique),
- *description*: optional, possibly longer description of the alternative,
- a set of *values*, so that one value is assigned to each :ref:`attribute <DexAttribute>`
  in the :ref:`tree of attributes <DexTree>`.
  
The set of values is further partitioned into:

-  *alternative 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 attributes are of different types, collectively referred to as :ref:`DEX values <DexValue>`.