Parameters of the high-fidelity solvers used for the 2D, 3D, and 3D unstructured cases.

Here, h is the element diameter, dt the time step, the stimulation duration, the membrane capacitance per unit surface area, , , the conductivities along the principal directions, and the amplitude of the applied stimulus current density and is the simulated physical time. The 2D case has been solved using MATLAB’s direct solver, while the 3D cases have been solved using the Conjugate Gradient (CG) solver provided by the PETSc library and Hypre BoomerAMG as preconditioner [4,59].