.. _variables-discrete_design_set-string:

""""""
string
""""""


String-valued discrete design set variables



**Topics**


discrete_variables, design_variables


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

   variables-discrete_design_set-string-elements_per_variable
   variables-discrete_design_set-string-elements
   variables-discrete_design_set-string-adjacency_matrix
   variables-discrete_design_set-string-initial_point
   variables-discrete_design_set-string-descriptors


**Specification**

- *Alias:* None

- *Arguments:* INTEGER

- *Default:* no discrete design set string variables


**Child Keywords:**

+-------------------------+--------------------+---------------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword            | Dakota Keyword Description                    |
|                         | Group              |                           |                                               |
+=========================+====================+===========================+===============================================+
| Optional                                     | `elements_per_variable`__ | Number of admissible elements for each set    |
|                                              |                           | variable                                      |
+----------------------------------------------+---------------------------+-----------------------------------------------+
| Required                                     | `elements`__              | The permissible values for each discrete      |
|                                              |                           | variable                                      |
+----------------------------------------------+---------------------------+-----------------------------------------------+
| Optional                                     | `adjacency_matrix`__      | 1-0 matrix defining which categorical         |
|                                              |                           | variable levels are related.                  |
+----------------------------------------------+---------------------------+-----------------------------------------------+
| Optional                                     | `initial_point`__         | Initial values for variables                  |
+----------------------------------------------+---------------------------+-----------------------------------------------+
| Optional                                     | `descriptors`__           | Labels for the variables                      |
+----------------------------------------------+---------------------------+-----------------------------------------------+

.. __: variables-discrete_design_set-string-elements_per_variable.html
__ variables-discrete_design_set-string-elements.html
__ variables-discrete_design_set-string-adjacency_matrix.html
__ variables-discrete_design_set-string-initial_point.html
__ variables-discrete_design_set-string-descriptors.html



**Description**


Discrete design variables whose values come from a specified set of
admissible strings.

See :ref:`variables:usage` for tips on specifying discrete set
variables. Each string element value must be quoted and may contain
alphanumeric, dash, underscore, and colon. White space, quote
characters, and backslash/metacharacters are not permitted.




**Examples**


Two string variables whose values will be selected from the set of
provided elements. The first variable, 'linear solver', takes on
values from a set of three possible elements and the second variable,
'mesh_file', from a set of two possible elements.


.. code-block::

    discrete_design_set
      string 2
        descriptors           'linear_solver'  'mesh_file'
        elements_per_variable 3                2
        elements              'cg' 'gmres' 'direct'
                              'mesh64.exo' 'mesh128.exo'




