simpeg.electromagnetics.time_domain.Simulation3DMagneticField.getAsubdiag#

Simulation3DMagneticField.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:

$${\mathbf{B}}_k=-\frac{1}{\mathrm{\Delta }{t}_k}{\mathbf{M}}_{\mathbf{e}\mu }$$

where $\mathrm{\Delta }{t}_k$ is the step-length and ${\mathbf{M}}_{\mathbf{e}\mu }$ is the permeability inner-product matrix on edges.

See the Notes section of the doc strings for Simulation3DMagneticField for a full description of the formulation.

Parameters:

tIndint

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

Returns:

(n_edges, n_edges) sp.sparse.csr_matrix

The sub-diagonal system matrix.