sources -- returns the sources of a digraph

Synopsis

Usage:

L = sources D
Inputs:
- D, an instance of the type Digraph, digraph whose sources we are searching for
Outputs:
- L, a list, list of all the sources (if there are any)

Description

A source of a Digraph D is a vertex of D that has no parents. That is, v is a source of D if and only if there are only edges pointing from v; none can be pointing into v (there is no edge of the form (v,u)).

i1 : D = digraph({a,b,c,d,e},{{a,b},{b,c},{b,d},{e,b}});

i2 : sources D

o2 = {a, e}

o2 : List

Ways to use `sources` :

"sources(Digraph)"

For the programmer

The object sources is a method function.

sources -- returns the sources of a digraph

Synopsis

Description

See also

Ways to use sources :

For the programmer

Ways to use `sources` :