Let $X$ be the mutation matrix of size $M \times N$. $N$ is the number of observations/samples.
Math {{< math >}} $$ \gamma_{n} = \frac{ \left | \left (\mathbf x_{n} - \mathbf x_{n-1} \right )^T \left [\nabla F (\mathbf x_{n}) - \nabla F (\mathbf x_{n-1}) \right ] \right |}{\left \|\nabla F(\mathbf{x}_{n}) - \nabla F(\mathbf{x}_{n-1}) \right \|^2} $$ {{< /math >}} renders as