.. _method-multilevel_sampling-export_sample_sequence:

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export_sample_sequence
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Enable export of multilevel/multifidelity sample sequences to individual files


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

   method-multilevel_sampling-export_sample_sequence-custom_annotated
   method-multilevel_sampling-export_sample_sequence-annotated
   method-multilevel_sampling-export_sample_sequence-freeform


**Specification**

- *Alias:* None

- *Arguments:* None


**Child Keywords:**

+-------------------------+--------------------+----------------------+-----------------------------------------------+
| Required/Optional       | Description of     | Dakota Keyword       | Dakota Keyword Description                    |
|                         | Group              |                      |                                               |
+=========================+====================+======================+===============================================+
| Optional (Choose One)   | Tabular Format     | `custom_annotated`__ | Export sample sequences enabling file format  |
|                         |                    |                      | customization                                 |
|                         |                    +----------------------+-----------------------------------------------+
|                         |                    | `annotated`__        | Export sample sequences with descriptors      |
|                         |                    +----------------------+-----------------------------------------------+
|                         |                    | `freeform`__         | Export sample sequences without heading       |
|                         |                    |                      | descriptors                                   |
+-------------------------+--------------------+----------------------+-----------------------------------------------+

.. __: method-multilevel_sampling-export_sample_sequence-custom_annotated.html
__ method-multilevel_sampling-export_sample_sequence-annotated.html
__ method-multilevel_sampling-export_sample_sequence-freeform.html



**Description**


When this option is active, separate output files are written for each
unique sample increment and are tagged by algorithm type, simulation
interface, iteration count, level count, and the number of samples as
described below.  The data content is comprised of the input variables
only, without corresponding responses, as an intended use case is to
support evaluation of these sample sets offline.

*Default Behavior*

If not specified, the ``annotated`` format is assumed.

*Expected Output*

Separate output files are generated according to the following format:
``{ml/cv}_{interface_id}_{iteration_number}_{level_number}_{number_of_samples}``.dat.

With respect to the algorithm type, interface id, and level counter, the
following definitions are employed:

- Multilevel MC with hierarchical model: ``ml_`` is pre-pended for all sample increments and sample sets are tagged with the interface id from the HF model.
- Control Variate MC with hierarchical model (deprecated): ``cv_`` is prepended for all sample increments, shared sample sets are tagged with the HF interface id, and LF-only refinements are tagged by the LF interface id.
- Multilevel-Control Variate MC with hierarchical model: employs a combination of exports from the two cases above.  ``ml_`` is pre-pended for all HF sample increments and sample sets are tagged with the interface id from the HF model; ``cv_`` is prepended for all LF increments and sample sets are tagged with the LF interface id.  Note that the LF model shares the same ``ml_`` sample sets, but a redundant file is not created for this data.
- Non-hierarchical approaches (Multifidelity MC, Approximate Control Variate): ``cv_`` is prepended for all sample increments and sample sets are tagged with the corresponding model interface id.  The level number corresponds to the index of the approximation model for LF increments and to the id of the truth model (number of LF approximations + 1) for shared increments.

With respect to iteration count, pilot samples are tagged with iteration 0.


