check_partition() is used to validate partition matrices.
check_partition(partition)two-dimensinal matrix of mode numeric with
rows as types, columns as subcommunities, and elements containing relative
abundances of types in subcommunities. In the case of phylogenetic
metacommunities, these are the relative abundances of terminal taxa.
Returns a two-dimensions matrix of mode numeric. If
the partition matrix was valid, this should be identical to that which was
input as an argument.