A module that allows to configure edge group constraints, interactively. Edge group constraints
are interpreted by some automatic layout algorithms like HierarchicLayouter
to combine edges that are grouped to bus-like structures.
Automatically group edges that share common source or target nodes. To avoid ambiguities, this method
will never assign edge A and edge B to the same group, if there is an edge C, that is grouped with either edge A, or node B,
but not with both.
Parameters:
graph - input graph
positiveEC - - returns edges for which port constraints will be assigned
sgMap - source group id map
tgMap - target group id map
shareGroupAtBothEnds - whether or not to assign the same groupID to both the source and target end of an edge.