.. _method-coliny_ea-fitness_type:

""""""""""""
fitness_type
""""""""""""


Select fitness type


.. toctree::
   :hidden:
   :maxdepth: 1

   method-coliny_ea-fitness_type-linear_rank
   method-coliny_ea-fitness_type-merit_function


**Specification**

- *Alias:* None

- *Arguments:* None

- *Default:* linear_rank


**Child Keywords:**

+-------------------------+--------------------+--------------------+---------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword     | Dakota Keyword Description                  |
|                         | Group              |                    |                                             |
+=========================+====================+====================+=============================================+
| Required (Choose One)   | Fitness Type       | `linear_rank`__    | Set selection scaling                       |
|                         |                    +--------------------+---------------------------------------------+
|                         |                    | `merit_function`__ | Balance goals of reducing objective         |
|                         |                    |                    | function and satisfying constraints         |
+-------------------------+--------------------+--------------------+---------------------------------------------+

.. __: method-coliny_ea-fitness_type-linear_rank.html
__ method-coliny_ea-fitness_type-merit_function.html



**Description**


The ``fitness_type`` controls how strongly differences in "fitness" (i.e., the objective function) are weighted in the process of selecting "parents" for crossover. It has two options, ``linear_rank`` and ``merit_function``.