Capacitances
The mutual capacitance, $c_{ij}$, between two contacts $i$ and $j$ can be calculated via
calculate_mutual_capacitance(sim, (i, j))
The weighting potentials of the two contacts must have already been calculated as they are needed in the calculation:
\[c_{ij} = \epsilon_0 \int_{World} \nabla \Phi_i^w(\vec{r}) ϵ_r(\vec{r}) \nabla \Phi_j^w(\vec{r}) d\vec{r}\]
The function returns the elements of the Maxwell capacitance matrix, $\mathbf{C}$, which fulfills
\[\vec{\mathbf{Q}} = \mathbf{C} \cdot \vec{\mathbf{V}}\]
The whole matrix can also be obtained via
calculate_capacitance_matrix(sim)