Gradient

The gradient, represented by $\nabla$, represents the vector pointing in the direction of the greatest rate of change. Given a vector $\vec{u}$, the gradient of $\vec{u}$ is calculated by

$$\nabla \vec{u}=\left(\frac{\partial \vec{u}}{\partial x},\frac{\partial \vec{u}}{\partial y},\frac{\partial \vec{u}}{\partial z}\right)$$