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Low-level (private) API: Classes and functions intended for use within :obj:`meep_adjoint`
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:class:`TimeStepper`: Interface to computational back-end provided by :codename:`meep` or other FDTD solver
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.. _TheTimeStepperClass:

.. autoclass:: meep_adjoint.TimeStepper
   :inherited-members:


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:class:`ObjectiveFunction`: Evaluation of objective-function values and partial derivatives
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.. _TheObjectiveFunctionClass:

.. autoclass:: meep_adjoint.ObjectiveFunction
   :inherited-members:


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:class:`DFTCell`: Storage for frequency-domain field components and evaluation of objective quantities
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.. _TheDFTCellClass:

.. autoclass:: meep_adjoint.DFTCell
   :inherited-members:

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:class:`Subregion`: Rationalized, unified handling of spatial subregions
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.. _TheSubregionClass:

.. autoclass:: meep_adjoint.Subregion
   :inherited-members: