.. _FileFunct:

Function Data File
------------------

Function data files are tab-delimited text files for storing
aggregation and discretization functions , which are exported and imported
through :ref:`File Menu <XMenuFile>` commands:
``File/Export function...`` and ``File/Import function...``, respectively.
One file contains one function, whose format can be specified with
:ref:`Import/Export settings <XSettingsImportExport>`.

Examples
~~~~~~~~

1. *TECH.CHAR.* function from the
`Car Evaluation <https://dex.ijs.si/documentation/DEX_Method/DEX_Car.html>`__ model,
exported in tab-delimited format, using 'Base 1' values and exporting
all rules. The character ``+`` represents an entered rule. Here, the TAB
character is denoted ``¬``.

| ``¬COMFORT¬SAFETY¬TECH.CHAR.``
| ``1¬1¬1¬1¬+``
| ``2¬2¬1¬1¬+``
| ``3¬3¬1¬1¬+``
| ``4¬1¬1¬1¬+``
| ``5¬2¬2¬2¬+``
| ``6¬3¬3¬3¬+``
| ``7¬1¬1¬1¬+``
| ``8¬2¬3¬3¬+``
| ``9¬3¬4¬4¬+``

2. The same function exported using text values and exporting only
entered rules (in this case there is no need to display the ``+`` or ``-``
entered status).

| ``¬COMFORT¬SAFETY¬TECH.CHAR.``
| ``1¬bad¬bad¬bad``
| ``2¬acc¬bad¬bad``
| ``3¬good¬bad¬bad``
| ``4¬bad¬bad¬bad``
| ``5¬acc¬acc¬acc``
| ``6¬good¬good¬good``
| ``7¬bad¬bad¬bad``
| ``8¬acc¬good¬good``
| ``9¬good¬exc¬exc``

3. *Experience* discretization function from the
`Employee Selection <https://dex.ijs.si/documentation/DEX_Method/DEX_Employee.html>`__ model,
using 'Base 1' values.

| ``¬ExperYears¬¬Experience``
| ``1¬¬¬1¬+``
| ``¬0¬]¬``
| ``2¬¬¬2¬+``
| ``¬1¬]¬``
| ``3¬¬¬3¬+``
| ``¬5¬]¬``
| ``4¬¬¬4¬+``
| ``¬10¬[¬``
| ``5¬¬¬5¬+``

Observe the alternating lines: lines beginning with 1 to 5 define output values of the corresponding input value intervals,
while the intermediate lines define interval boundaries. The characters ``]`` and ``[`` determine which interval,
previous or next, contains the corresponding bound. In this case, there are 5 intervals:

- [-∞, 0] -> value 1 ("no")
- (0, 1] -> value 2 ("to1year")
- (1, 5] -> value 3 ("1-5")
- (5, 10) -> value 4 ("6-10")
- [10, +∞] -> value 5 ("more")

.. toctree::
  :hidden: