@classmethod<EOL><INDENT>def from_coordinates(cls, coordinates, labels):<DEDENT>
from molmod.ext import molecules_distance_matrix<EOL>distance_matrix = molecules_distance_matrix(coordinates)<EOL>return cls(distance_matrix, labels)<EOL>
Initialize a similarity descriptor

           Arguments:
             coordinates  --  a Nx3 numpy array
             labels  --  a list with integer labels used to identify atoms of
                         the same type