Computing even cycles in graphs
Algorithm designed
by N. Robertson, P.D. Seymour and
R. Thomas
(
Permanents, Pfaffian orientations, and even directed circuits)
programmed by
Christopher Carl Heckman,
web interface by
Petr Hlineny.
Best viewed with Netscape!
A short guide
Use your mouse to draw the graph you want to test.
The left button creates new vertices,
or new edges starting in existing vertices.
An edge can have arbitrarily many bends.
To end an edge in a new vertex, use double-click.
Esc cancels current drawing.
The middle button (or shif + left button)
allows you to pick a vertex or an edge,
and either move it with the mouse or delete it
with the Del key.
You may easily add new bends to edges,
to remove a bend, pick it as above and press Esc.
Press the Clear button to start with a new graph,
use the top line buttons to move or scale the picture.
Press the CYCLE button to call the algorithm
(through CGI...),
then see the bottom line (and the picture) for results.