.. _method-bayes_calibration-model_discrepancy-export_corrected_variance_file:

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export_corrected_variance_file
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Output file for prediction variance calculations


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

   method-bayes_calibration-model_discrepancy-export_corrected_variance_file-custom_annotated
   method-bayes_calibration-model_discrepancy-export_corrected_variance_file-annotated
   method-bayes_calibration-model_discrepancy-export_corrected_variance_file-freeform


**Specification**

- *Alias:* None

- *Arguments:* STRING

- *Default:* corrected model variance export to default filename


**Child Keywords:**

+-------------------------+--------------------+----------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword       | Dakota Keyword Description                    |
|                         | Group              |                      |                                               |
+=========================+====================+======================+===============================================+
| Optional (Choose One)   | Tabular Format     | `custom_annotated`__ | Selects custom-annotated tabular file format  |
|                         |                    +----------------------+-----------------------------------------------+
|                         |                    | `annotated`__        | Selects annotated tabular file format         |
|                         |                    +----------------------+-----------------------------------------------+
|                         |                    | `freeform`__         | Selects freeform file format                  |
+-------------------------+--------------------+----------------------+-----------------------------------------------+

.. __: method-bayes_calibration-model_discrepancy-export_corrected_variance_file-custom_annotated.html
__ method-bayes_calibration-model_discrepancy-export_corrected_variance_file-annotated.html
__ method-bayes_calibration-model_discrepancy-export_corrected_variance_file-freeform.html



**Description**


Enables the user to specify the name and format of the file to which
corrected model variance information is output. The file will contain the
values of the variances computed at those points specified with
``num_predictions``, ``prediction_configs``, or ``import_prediction_configs``.

For scalar responses, the prediction variance for each observable :math:`d_i`  is
calculated according to


.. math:: 

   \Sigma_{total}(x) = \Sigma_{\delta}(x) + \sigma^2_{exp}I.

Here, :math:`\Sigma_{\delta}(x)`  is the (co)variance calculated from the
Gaussian process or polynomial regression model, details of which can be
found in the Dakota User's and Theory Manuals. If experimental variance
information is provided for the calibration, the maximum variance found for
the observable :math:`d_i`  is used as :math:`\sigma^2_{exp}` . For more details,
see the Dakota User's and Theory Manuals. For field responses, the variance
of the discrepancy model alone is output to this file.

*Default Behavior*

If ``export_corrected_variance_file`` is not specified, information will be
automatically output to ``dakota_discrepancy_variance_tabular``.dat.

*Usage Tips*

Dakota exports tabular data in one of three formats:

- ``annotated`` (default)
- ``custom_annotated``
- ``freeform``


