Partial derivative of a function with respect to a vector

Partial derivative of a function with respect to a vector

I have the following error term E:
$$E = \frac{1}{c}\sum_{\substack{ i<j}} \frac{[d_{ij}^* -
d_{ij}]^2}{d_{ij}^*}$$
where
$$c = \sum_{\substack{ i<j}}d_{ij}^*$$
and
$$d_{ij} = \sqrt{\sum_{\substack{k=1}}^{d} [ y_{ik} - y_{jk}]^2}$$
$d_{ij}^*$ have the same equation as above but its values are constant but
the measures are in $\mathbb{R}^{N}$ and $N > d$ .
I need step by step explanation on finding the partial derivative
$\frac{\partial E}{\partial y_{pq}}$ which is given below.
$$\frac{\partial E}{\partial y_{pq}} = \frac{-2}{c}\sum_{\substack{
j=1,j\neq p}}^{N} \left[\frac{d_{pj}^* -
d_{pj}}{d_{pj}d_{pj}^*}\right](y_{pq} - y_{jq}) $$