How to compute the rank of a Delaunay polytope

Roughly speaking, the rank of a Delaunay polytope (first introduced in \cite{DGL92}) is its number of degrees of freedom. In \cite{DL}, a method for computing the rank of a Delaunay polytope $P$ using the hypermetrics related to $P$ is given. Here a simpler more efficient method, which uses affine dependencies instead of hypermetrics is given. This method is applied to classical Delaunay polytopes. Then, we give an example of a Delaunay polytope, which does not have any affine basis.