Dakota Reference Manual: string

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string

Discrete, epistemic uncertain variable - strings within a set

## Topics

This keyword is related to the topics:

- discrete_variables
- epistemic_uncertain_variables

## Specification

Alias: none

Argument(s): INTEGER

Default: no discrete uncertain set string variables

Child Keywords:

| Required/Optional | Description of Group | Dakota Keyword | Dakota Keyword Description
--- | --- | --- | --- | ---
| Optional | elements_per_variable | Number of admissible elements for each set variable
| Required | elements | The permissible values for each discrete variable
| Optional | set_probabilities | This keyword defines the probabilities for the various elements of discrete sets.
| Optional | initial_point | Initial values for variables
| Optional | descriptors | Labels for the variables

## Description

Discrete set variables may be used to specify categorical choices which are epistemic. For example, if we have three possible forms for a physics model (model 1, 2, or 3) and there is epistemic uncertainty about which one is correct, a discrete uncertain set may be used to represent this type of uncertainty.

This variable is defined by a set of strings, in which the discrete value may take any value within the string set (for example, the set may be defined as 'coarse', 'medium', and 'fine')

Other epistemic types include:

- continuous_interval_uncertain
- discrete_interval_uncertain
- discrete_uncertain_set integer
- discrete_uncertain_set real

## Examples

    discrete_uncertain_set
     string
     num_set_values 2             3
     set_values     'red' 'blue'  'coarse' 'medium' 'fine'
     descriptors    'ds1'         'ds2'