Example: Some Car Option Analyses
=================================

This example shows some option analysis reports that can be obtained in
:doc:`DEXi <DEXi>` using the :doc:`Car Evaluation Model <DEXiCar>`.
These reports can be created by commands of the :doc:`Analysis
Menu <DEXiIntMenuAnal>` or corresponding buttons on the
:doc:`Evaluation Page <DEXiIntTabEval>`.

Plus-minus-1 analysis
---------------------

This example shows results of "Plus-minus-1 analysis" for the option
*Car2* and the aggregate attribute CAR. The column **Car2** displays the
current values of *Car2*. The column **-1** displays the values of the
attribute **CAR** when each corresponding lower-level attribute's value
changes by one step down (independently of other attributes). Similarly,
the column **+1** shows the effects of increasing the value by one step
up. Empty fields denote no effect, and the brackets '[' and ']' indicate
that the attribute value cannot be decreased or increased, respectively.

.. image:: images/CarPM.png
   :alt: Car: Plus-minus-1 Analysis

The above display shows, for example, that BUY. PRICE considerably
affects the evaluation of *Car2*. When BUY. PRICE decreases by one step
(from 'medium' to 'high'; the latter value is not shown), the overal
value of CAR becomes 'unacc'. In the other direction (from 'medium' to
'low'), the overall evaluation improves to 'exc'.

The two brackets ']' indicate that the values of corresponding
attributes, #PERS and LUGGAGE, cannot be increased any more, preventing
the **+1** part of the analysis.

Selective explanation
---------------------

Selective explanation highlights particular advantages and disadvantages
of an option. The method finds and displays only those connected
sub-trees of attributes for which the option has been evaluated as
particularly good or bad.

.. image:: images/CarSel.png
   :alt: Car: Selective Explanation

This example shows that *Car2* has three particularly strong parts (two
sub-trees and one single attribute):

#. overall evaluation, which is strongly influenced by low MAINT. PRICE,
#. COMFORT due to very good #PERS and LUGGAGE, and
#. high SAFETY.

Compare options
---------------

This analysis compares one (primary) option with some other selected
(secondary) options, displaying all values of the primary option and
only those values of the secondary options that differ from the
primary's ones.

.. image:: images/CarComp.png
   :alt: Car: Compare Options

This example compares *Car1* (primary option) with *Car2* (secondary
option). *Car2* differs from *Car1* in the values of basic attributes
MAINT. PRICE and SAFETY, which cause different evaluations of TECH.
CHAR, PRICE and CAR.

.. toctree::
  :hidden: