[Nauty] Schreir Sims Representation

[Bulutoglu Dursun A Civ AFIT/ENC]

	I was wondering where I could find the "random Schreier"
Algorithm for changing the base. I need the best known algorithm to make
a change of base.
	Dursun.

 It is possible to control the base used by nauty according to its
combinatorial properties; for example, you could ensure that each
element in the base is adjacent to one of the provious elements.
However, there is no way to specify an actual base.  The best option
would be to find the group and then do a change of base on it.  Probably
the "random Schreier" method would be best for this.  Presently I have
no software for this, but I should have.


If the base has vertices that are not really necessary, then there are
no generators (except the identity) at the levels corresponding to those
vertices.  It would not be a very serious inefficiency.

Changing the base using "random Schreier" would take more time than
nauty takes for easy graphs with large groups and less time for
difficult graphs.  So it depends on the application.

Brendan.

_