simpeg.electromagnetics.time_domain.Simulation3DElectricField.getAsubdiag#

Simulation3DElectricField.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:

\[\mathbf{B}_k = -\frac{1}{\Delta t_k} \mathbf{M_{e\sigma}}\]

where \(\Delta t_k\) is the step-length and \(\mathbf{M_{e \sigma}}\) is the conductivity inner-product matrix on edges.

See the Notes section of the doc strings for Simulation3DElectricField 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.