7,111
edits
(→On a twodimensional rectangular grid: The definition of the laplacian has still the wrong sign) 
(→On a twodimensional rectangular grid: We need to switch sign of b, though, if we switch sign of A and D) 

:<math>
b =
\Delta x^2\begin{bmatrix} g_{11} , g_{21} , \ldots , g_{m1} , g_{12} , g_{22} , \ldots , g_{m2} , \ldots , g_{mn}
\end{bmatrix}^T.
</math>
