Diagonal entries in adjacency matrix


I have a simple Metis question to which I didn't find answer by quick googling. Are diagonal entries (v,v) allowed in adjacency matrix? I mean, if node v is allowed to be connected to itself. It seems to work in my small tests, but should it?

Thanks in advance,

Dr. Lauri Lehtovaara
LPMCN, University Lyon 1, France

RE: Diagonal entries should not

Diagonal entries should not be included.