simpeg.electromagnetics.natural_source.Simulation3DPrimarySecondary.getADeriv#

Simulation3DPrimarySecondary.getADeriv(freq, u, v, adjoint=False)[source]#

Derivative operation for the system matrix times a vector.

The system matrix at each frequency is given by:

\[\mathbf{A} = \mathbf{C^T M_{f\frac{1}{\mu}} C} + i\omega \mathbf{M_{e\sigma}}\]

where

  • \(\mathbf{M_{e\sigma}}\) is the inner-product matrix for conductivities projected to edges

  • \(\mathbf{M_{f\frac{1}{\mu}}}\) is the inner-product matrix for inverse permeabilities projected to faces

See the Notes section of the doc strings for Simulation3DElectricField for a full description of the formulation.

Where \(\mathbf{m}\) are the set of model parameters defining the electromagnetic properties \(\mathbf{v}\) is a vector and \(\mathbf{e}\) is the discrete electric field solution, this method assumes the discrete solution is fixed and returns

\[\frac{\partial (\mathbf{A \, e})}{\partial \mathbf{m}} \, \mathbf{v}\]

Or the adjoint operation

\[\frac{\partial (\mathbf{A \, e})}{\partial \mathbf{m}}^T \, \mathbf{v}\]
Parameters:
freqfloat

The frequency in Hz.

u(n_edges,) numpy.ndarray

The solution for the fields for the current model at the specified frequency.

vnumpy.ndarray

The vector. (n_param,) for the standard operation. (n_edges,) for the adjoint operation.

adjointbool

Whether to perform the adjoint operation.

Returns:
numpy.ndarray

Derivative of system matrix times a vector. (n_edges,) for the standard operation. (n_param,) for the adjoint operation.