Samples variables as a specified values

Topics

This keyword is related to the topics:

parameter_studies

Specification

Alias: none

Argument(s): none

Required/Optional

Description of Group

Dakota Keyword

Dakota Keyword Description

Required

(Choose One)

Group 1

list_of_points

List of variable values to evaluate in a list parameter study

import_points_file

File containing variable values and corresponding responses

Optional

model_pointer

Identifier for model block to be used by a method

Description

Dakota's list parameter study allows for evaluations at user selected points of interest.

Default Behavior

By default, the list parameter study operates over all types of variables.

The number of real values in the list_of_points specification or file referenced by import_points_file must be a multiple of the total number of variables (including continuous and discrete types) contained in the variables specification.

Expected Outputs

A list parameter study produces a set of responses for each parameter set that is specified.

Usage Tips

This parameter study simply performs simulations for the first parameter set (the first n entries in the list), followed by the next parameter set (the next n entries), and so on, until the list of points has been exhausted.
Since the initial values from the variables specification will not be used, they need not be specified.
For discrete set types, the actual values should be specified, not the set indices, although the values will be validated for membership within the set value specifications.

Examples

This shows the method and variables block of a Dakota input file that runs a list_parameter_study.

method
  list_parameter_study
    list_of_points =
                 3.1e6    0.0029    0.31  
                 3.2e6    0.0028    0.32 
                 3.3e6    0.0027    0.34 
                 3.3e6    0.0026    0.36  

variables
  continuous_design = 3
    descriptors = 'E'    'MASS'     'DENSITY'

Note that because of the way Dakota treats whitespace, the above example is equivalent to:

method
  list_parameter_study
    list_of_points =
3.1e6    0.0029    0.31  3.2e6    0.0028    
0.32    3.3e6    0.0027    
0.34  3.3e6    0.0026    0.36

variables
  continuous_design = 3
    descriptors = 'E'  'MASS'   'DENSITY'

Although the first example is much more readable.

And here's a full input file:

# tested on Dakota 6.0 on 140501
environment
  tabular_data
    tabular_data_file 'List_param_study.dat'

method
  list_parameter_study
    list_of_points =     0.1    0.1
                         0.2    0.1
                         0.3    0.0
                         0.3    1.0

model
  single

variables
  active design
  continuous_design = 2
    descriptors    'x1' 'x2'
  continuous_state = 1
    descriptors =   'constant1'
    initial_state = 100

interface
  analysis_drivers 'text_book'
    fork
  asynchronous
    evaluation_concurrency 2

responses
  response_functions = 1
  no_gradients
  no_hessians

This example illustrates the list_parameter_study.

The function evaluations are independent, so any level of evaluation_concurrency can be used
Default behavior for parameter studies is to iterate on all variables. However, because active design is specified, this study will only iterate on the continuous_design variables.

Topics

Specification

Description

Examples

See Also