indexLabelGraph(MixedGraph) -- relabel the vertices of a mixed graph according to their indices, indexed from 0

Description

This method relabels the vertices of a graph of class MixedGraph according to their indices. The method indexes from 0 to the number of vertices minus one. This is an adaptation of the method indexLabelGraph.

 i1 : G= mixedGraph(graph{{a,b},{b,c}},digraph {{a,d},{c,e},{f,g}},bigraph {{d,e}}) o1 = MixedGraph{Bigraph => Bigraph{d => {e}}} e => {d} Digraph => Digraph{a => {d}} c => {e} d => {} e => {} f => {g} g => {} Graph => Graph{a => {b} } b => {a, c} c => {b} o1 : MixedGraph i2 : indexLabelGraph G o2 = MixedGraph{Bigraph => Bigraph{1 => {2}}} 2 => {1} Digraph => Digraph{0 => {2}} 1 => {} 2 => {} 3 => {4} 4 => {} 5 => {1} Graph => Graph{0 => {6} } 5 => {6} 6 => {5, 0} o2 : MixedGraph