Suppose I have a real-valued function $f$ defined on the grid $$\{ (n, m) : n, m \in \mathbb{Z}, 0 \leq n, m \leq 10.\}$$
How would I define the $(H^1)^{*}$ norm of this function in such a way that it's computable (eg. in Matlab), i.e., the dual space norm?