simpeg.electromagnetics.frequency_domain.Simulation3DCurrentDensity.getADeriv_rho#

Simulation3DCurrentDensity.getADeriv_rho(freq, u, v, adjoint=False)[source]#

Resistivity derivative operation for the system matrix times a vector.

The system matrix at each frequency is given by:

\[\mathbf{A} = \mathbf{C M_{e\mu}^{-1} C^T M_{f\rho}} + i\omega \mathbf{I}\]

where

  • \(\mathbf{M_{f\rho}}\) is the inner-product matrix for resistivities projected to faces

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

See the Notes section of the doc strings for Simulation3DCurrentDensity for a full description of the formulation.

Where \(\mathbf{m}_\boldsymbol{\rho}\) are the set of model parameters defining the resistivity, \(\mathbf{v}\) is a vector and \(\mathbf{j}\) is the discrete current density solution, this method assumes the discrete solution is fixed and returns

\[\frac{\partial (\mathbf{A \, j})}{\partial \mathbf{m}_\boldsymbol{\sigma}} \, \mathbf{v}\]

Or the adjoint operation

\[\frac{\partial (\mathbf{A \, j})}{\partial \mathbf{m}_\boldsymbol{\sigma}}^T \, \mathbf{v}\]
Parameters:
freqfloat

The frequency in Hz.

u(n_faces,) 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_faces,) for the adjoint operation.

adjointbool

Whether to perform the adjoint operation.

Returns:
numpy.ndarray

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