.. _method-moga-niching_type-max_designs:

"""""""""""
max_designs
"""""""""""


Limit number of solutions to remain in the population


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

   method-moga-niching_type-max_designs-num_designs


**Specification**

- *Alias:* None

- *Arguments:* REALLIST


**Child Keywords:**

+-------------------------+--------------------+--------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword     | Dakota Keyword Description                    |
|                         | Group              |                    |                                               |
+=========================+====================+====================+===============================================+
| Optional                                     | `num_designs`__    | Limit the number of solutions                 |
+----------------------------------------------+--------------------+-----------------------------------------------+

.. __: method-moga-niching_type-max_designs-num_designs.html



**Description**


The ``max_designs`` niche pressure applicator is designed to choose a
limited number of solutions to remain in the population.  That number
is specified by ``num_designs``.  It does so in order to balance the
tendency for populations to grow very large and thus consuming too
many computer resources.  It operates by ranking designs according to
their fitness standing and a computed count of how many other designs
are too close to them.  Too close is a function of the supplied
niche_vector, which specifies the minimum distance between any two
points in the performance space along each dimension individually.
Once the designs are all ranked, the top c\ num_designs designs are
kept in the population and the remaining ones are bufferred or
discarded.  Note that like other niching operators, this one will not
discard an extreme design.


