Fig 2. The four relative metrics as a function of the key parameter Δt (the time step), for four selected values of α.

The solution is computed for all values of α on the time interval [0,500 ms] with N = 400. All relative errors are evaluated by comparing the solution for a specific combination of α and Δt with the solution obtained for the same α when Δt = 6.25⋅10⁻⁴ ms. In all simulations, the stimulus I _stim = 40 μA⋅cm⁻³ was applied on [0,0.05 cm] at t _stim = 10 ms for two consecutive milliseconds and then removed.