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.. manual/packages/vertex-cfd/nonlinear_solve_solver_options.rst
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.. _sec_nonlinear_solve_solver_options:

********************
NOX Solver Options
********************

The ``Solver Options`` sublist controls status-test evaluation and
fixed-point solver behavior.

.. dropdown:: <Solver Options>
   :icon: multi-select
   :color: primary
   :animate: fade-in-slide-down

   .. py:data:: Status Test Check Type

      :type: string
      :value: ``"Complete"``, ``"Minimal"``, or ``"None"``
      :usage: Optional
      :default: ``"Minimal"``
      :description: Controls how NOX evaluates the status-test tree. ``"Minimal"`` may stop after the overall result is known. ``"Complete"`` evaluates every test in the tree. ``"None"`` asks individual status tests to skip evaluation when supported.

   .. py:data:: Fixed Point Iteration Type

      :type: string
      :value: ``"Seidel"`` or ``"Jacobi"``
      :usage: Optional for the NOX multiphysics fixed-point solver
      :default: ``"Seidel"``
      :description: Selects sequential Seidel updates or simultaneous Jacobi updates. The standard Vertex-CFD line-search configuration does not use this entry.

   .. note::

      Do not set ``Observer`` or ``User Defined Pre/Post
      Operator`` in XML. Immediately before constructing the
      Tempus integrator, Vertex-CFD overwrites ``User Defined
      Pre/Post Operator`` with its own NOX observer vector. NOX
      rejects a list containing both observer entries. ``User
      Defined Merit Function`` is likewise a C++ object entry, not
      an XML-selectable algorithm name.

Example
-------

.. literalinclude:: ../../../../examples/inputs/simple_box_2d.xml
   :language: xml
   :linenos:
   :start-at: <ParameterList name="Solver Options">
   :end-at: </ParameterList> <!-- Solver Options -->
   :emphasize-lines: 2
   :caption: Minimal status-test evaluation used by a Vertex-CFD implicit solve.