.. _non_consistency_solver_parameters:

Nonlinear solver for consistent initialization
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Group /input/model/unit_XXX/discretization/consistency_solver - Nonlinear consistency solver paramters
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The following specifications of the nonlinear solver for consistent initialization are available.
The default is a ``COMPOSITE`` solver that applies multiple solvers subsequently, where the default is ``ATRN_ERR`` followed by ``LEVMAR``.


``SOLVER_NAME``

Name of the solver.
Available solvers are

- ``LEVMAR``: Levenberg-Marquardt method (ported from the MATLAB implementation)

- ``ATRN_RES``: Adaptive trust-region Newton solver, implemetation of the NLEQ-RES algorithm described in :cite:`Deuflhard2011` (p. 131)

- ``ATRN_ERR``: Robust adaptive trust-region Newton solver, implemetation of the NLEQ-ERR algorithm described in :cite:`Deuflhard2011` (pp. 148)

- ``PTC``: Pseudo-transient continuation method, see :cite:`Deuflhard2011` (section 6.4)

- ``COMPOSITE``: Applies multiple solvers subsequently


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   **Type:** string  **Length:** :math:`1`     
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``SUBSOLVERS``

Vector with names of solvers for the ``COMPOSITE`` solver (only required for composite solver). See ``SOLVER_NAME`` for available solvers.

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   **Type:** string  **Length:** :math:`\gt 1`     
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``INIT_DAMPING``

Initial damping factor (default is :math:`0.01`), only required for ``LEVMAR``, ``ATRN_RES`` and ``ATRN_ERR``. See ``SOLVER_NAME`` for available solvers.

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   **Type:** double  **Range:** :math:`\ge 0`       **Length:** :math:`1`
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``MIN_DAMPING``

Minimal damping factor (default is :math:`0.0001`), only required for ``ATRN_RES`` and ``ATRN_ERR``. See ``SOLVER_NAME`` for available solvers.

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   **Type:** double  **Range:** :math:`\ge 0`       **Length:** :math:`1`
   ================  =============================  ==================================