Editing Distance (graph theory) (section)

==Algorithm for finding pseudo-peripheral vertices==
Often peripheral [[sparse matrix]] algorithms need a starting vertex with a high eccentricity. A peripheral vertex would be perfect, but is often hard to calculate. In most circumstances a pseudo-peripheral vertex can be used.  A pseudo-peripheral vertex can easily be found with the following algorithm:

# Choose a vertex <math>u</math>.
# Among all the vertices that are as far from <math>u</math> as possible, let <math>v</math> be one with minimal [[degree (graph theory)|degree]].
# If <math>\epsilon(v) > \epsilon(u)</math> then set <math>u=v</math> and repeat with step 2, else <math>u</math> is a pseudo-peripheral vertex.