I have a vector function: $f(r)=[f_{x}(r), f_{y}(r), f_{z}(r)]$, where $ r=[x, y, z]. $
How to calculate the derrivative: $ \frac{d f(r)}{d r}$ ?
Will it be a matrix m of elements $ m_{ij}=\frac{\partial f_{i}(r)}{\partial j} $?
Does it have something to do with the Jacobian matrix?