Inputs:

$-$ Xs: A list of length L$,$ containing numpy arrays of shape $($N$,$ M$)$

Returns:

A numpy array R of shape $($L$,$ L$)$ where R$[$i$,$ j$]$ is the Euclidean distance

between C$[$i$]$ and C$[$j$],$ where C$[$i$]$ is an M$-$dimensional vector giving the

centroid of Xs$[$i$]$