.. _method-bayes_calibration-queso-emulator-ml_pce:

""""""
ml_pce
""""""


Multilevel Polynomial Chaos Expansion as an emulator model.


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

   method-bayes_calibration-queso-emulator-ml_pce-allocation_control
   method-bayes_calibration-queso-emulator-ml_pce-discrepancy_emulation
   method-bayes_calibration-queso-emulator-ml_pce-expansion_order_sequence
   method-bayes_calibration-queso-emulator-ml_pce-orthogonal_least_interpolation
   method-bayes_calibration-queso-emulator-ml_pce-askey
   method-bayes_calibration-queso-emulator-ml_pce-wiener
   method-bayes_calibration-queso-emulator-ml_pce-normalized
   method-bayes_calibration-queso-emulator-ml_pce-export_expansion_file
   method-bayes_calibration-queso-emulator-ml_pce-diagonal_covariance
   method-bayes_calibration-queso-emulator-ml_pce-full_covariance


**Specification**

- *Alias:* None

- *Arguments:* None


**Child Keywords:**

+-------------------------+--------------------+---------------------------+---------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword            | Dakota Keyword Description                  |
|                         | Group              |                           |                                             |
+=========================+====================+===========================+=============================================+
| Optional                                     | `allocation_control`__    | Sample allocation approach for multilevel   |
|                                              |                           | expansions                                  |
+----------------------------------------------+---------------------------+---------------------------------------------+
| Optional                                     | `discrepancy_emulation`__ | Formulation for emulation of model          |
|                                              |                           | discrepancies.                              |
+-------------------------+--------------------+---------------------------+---------------------------------------------+
| Optional (Choose One)   | Basis Polynomial   | `askey`__                 | Select the standardized random variables    |
|                         | Family             |                           | (and associated basis polynomials) from the |
|                         |                    |                           | Askey family that best match the            |
|                         |                    |                           | user-specified random variables.            |
|                         |                    +---------------------------+---------------------------------------------+
|                         |                    | `wiener`__                | Use standard normal random variables (along |
|                         |                    |                           | with Hermite orthogonal basis polynomials)  |
|                         |                    |                           | when transforming to a standardized         |
|                         |                    |                           | probability space.                          |
+-------------------------+--------------------+---------------------------+---------------------------------------------+
| Optional                                     | `normalized`__            | The normalized specification requests       |
|                                              |                           | output of PCE coefficients that correspond  |
|                                              |                           | to normalized orthogonal basis polynomials  |
+----------------------------------------------+---------------------------+---------------------------------------------+
| Optional                                     | `export_expansion_file`__ | Export the coefficients and multi-index of  |
|                                              |                           | a Polynomial Chaos Expansion (PCE) to a     |
|                                              |                           | file                                        |
+-------------------------+--------------------+---------------------------+---------------------------------------------+
| Optional (Choose One)   | Covariance Type    | `diagonal_covariance`__   | Display only the diagonal terms of the      |
|                         |                    |                           | covariance matrix                           |
|                         |                    +---------------------------+---------------------------------------------+
|                         |                    | `full_covariance`__       | Display the full covariance matrix          |
+-------------------------+--------------------+---------------------------+---------------------------------------------+

.. __: method-bayes_calibration-queso-emulator-ml_pce-allocation_control.html
__ method-bayes_calibration-queso-emulator-ml_pce-discrepancy_emulation.html
__ method-bayes_calibration-queso-emulator-ml_pce-askey.html
__ method-bayes_calibration-queso-emulator-ml_pce-wiener.html
__ method-bayes_calibration-queso-emulator-ml_pce-normalized.html
__ method-bayes_calibration-queso-emulator-ml_pce-export_expansion_file.html
__ method-bayes_calibration-queso-emulator-ml_pce-diagonal_covariance.html
__ method-bayes_calibration-queso-emulator-ml_pce-full_covariance.html



**Description**


Selects a multilevel polynomial chaos expansion (ML PCE) surrogate model
to use in the Bayesian likelihood calculations.  Most specification options are
carried over for using ML PCE as a surrogate within the Bayesian framework.