.. _method-multilevel_polynomial_chaos-expansion_order_sequence:

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expansion_order_sequence
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Sequence of expansion orders used in a multi-stage expansion


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

   method-multilevel_polynomial_chaos-expansion_order_sequence-dimension_preference
   method-multilevel_polynomial_chaos-expansion_order_sequence-basis_type
   method-multilevel_polynomial_chaos-expansion_order_sequence-collocation_ratio
   method-multilevel_polynomial_chaos-expansion_order_sequence-expansion_samples_sequence
   method-multilevel_polynomial_chaos-expansion_order_sequence-import_build_points_file


**Specification**

- *Alias:* None

- *Arguments:* INTEGERLIST


**Child Keywords:**

+-------------------------+--------------------+--------------------------------+--------------------------------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword                 | Dakota Keyword Description                                         |
|                         | Group              |                                |                                                                    |
+=========================+====================+================================+====================================================================+
| Optional                                     | `dimension_preference`__       | A set of weights specifying the realtive importance of each        |
|                                              |                                | uncertain variable (dimension)                                     |
+----------------------------------------------+--------------------------------+--------------------------------------------------------------------+
| Optional                                     | `basis_type`__                 | Specify the type of basis truncation to be used for a Polynomial   |
|                                              |                                | Chaos Expansion.                                                   |
+-------------------------+--------------------+--------------------------------+--------------------------------------------------------------------+
| Required (Choose One)   | Required (Choose   | `collocation_ratio`__          | Set the number of points used to build a PCE via regression to be  |
|                         | One)               |                                | proportional to the number of terms in the expansion.              |
|                         |                    +--------------------------------+--------------------------------------------------------------------+
|                         |                    | `expansion_samples_sequence`__ | Sequence of expansion samples used in a multi-stage polynomial     |
|                         |                    |                                | chaos expansion Each level entry of the                            |
|                         |                    |                                | ``expansion_samples_sequence`` applies to one expansion within a   |
|                         |                    |                                | multi-stage expansion. Current multi-stage expansions that support |
|                         |                    |                                | expansion samples sequences include multilevel and multifidelity   |
|                         |                    |                                | polynomial chaos. If adaptive refinement is active, then this      |
|                         |                    |                                | sequence specifies the starting point for each level within either |
|                         |                    |                                | an individual or integrated refinement approach. A corresponding   |
|                         |                    |                                | scalar specification is documented at, e.g.,                       |
|                         |                    |                                | :dakkw:`method-polynomial_chaos-expansion_order-expansion_samples` |
+-------------------------+--------------------+--------------------------------+--------------------------------------------------------------------+
| Optional                                     | `import_build_points_file`__   | File containing points you wish to use to build a surrogate        |
+----------------------------------------------+--------------------------------+--------------------------------------------------------------------+

.. __: method-multilevel_polynomial_chaos-expansion_order_sequence-dimension_preference.html
__ method-multilevel_polynomial_chaos-expansion_order_sequence-basis_type.html
__ method-multilevel_polynomial_chaos-expansion_order_sequence-collocation_ratio.html
__ method-multilevel_polynomial_chaos-expansion_order_sequence-expansion_samples_sequence.html
__ method-multilevel_polynomial_chaos-expansion_order_sequence-import_build_points_file.html



**Description**


Each level entry of the ``expansion_order_sequence`` applies to one
expansion within a multi-stage expansion.  Current multi-stage
expansions that support expansion order sequences include multilevel
or multifidelity polynomial chaos.

If adaptive refinement is active, then this sequence specifies the
starting point for each level within either an individual or
integrated refinement approach.

A corresponding scalar specification is documented at, e.g.,
:dakkw:`method-polynomial_chaos-expansion_order`