simpeg.electromagnetics.time_domain.Simulation3DCurrentDensity.getAsubdiag#

Simulation3DCurrentDensity.getAsubdiag(tInd)[source]#

Sub-diagonal system matrix for the time-step index provided.

This method returns the sub-diagonal system matrix for the time-step index provided:

$${\mathbf{B}}_k=-\frac{1}{\mathrm{\Delta }{t}_k}\mathbf{I}$$

where $\mathrm{\Delta }{t}_k$ is the step-length and $\mathbf{I}$ is the identity matrix.

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

Parameters:

tIndint

The time-step index; between [0, n_steps-1].

Returns:

(n_faces, n_faces) sp.sparse.csr_matrix

The sub-diagonal system matrix.