One vertex: ( ) Vertex with multiple edges, IGRAPH_IN, IGRAPH_MULTIPLE: ( 5 4 ) Vertex with multiple edges, IGRAPH_OUT, IGRAPH_MULTIPLE: ( 0 1 ) Vertex with multiple edges, IGRAPH_ALL, IGRAPH_MULTIPLE: ( 0 1 5 4 ) Vertex with multiple edges, undirected, IGRAPH_MULTIPLE: ( 0 5 4 1 ) Vertex with multiple edges, IGRAPH_IN, IGRAPH_NO_MULTIPLE: ( 5 ) Vertex with multiple edges, IGRAPH_OUT, IGRAPH_NO_MULTIPLE: ( 0 1 ) Vertex with multiple edges, IGRAPH_ALL, IGRAPH_NO_MULTIPLE: ( 0 1 ) Vertex with multiple edges, undirected, IGRAPH_NO_MULTIPLE: ( 0 5 ) Vertex 1 with loop, IGRAPH_OUT, IGRAPH_NO_LOOPS: ( 3 ) Vertex 1 with loop, IGRAPH_ALL, IGRAPH_NO_LOOPS: ( 0 3 ) Vertex 1 with loop, undirected, IGRAPH_NO_LOOPS: ( 0 3 ) Vertex 1 with loop, IGRAPH_OUT, IGRAPH_LOOPS_ONCE: ( 2 3 ) Vertex 1 with loop, IGRAPH_ALL, IGRAPH_LOOPS_ONCE: ( 0 2 3 ) Vertex 1 with loop, undirected, IGRAPH_LOOPS_ONCE: ( 0 2 3 ) Vertex 1 with loop, IGRAPH_ALL, IGRAPH_LOOPS_TWICE: ( 0 2 2 3 ) Vertex 1 with loop, undirected, IGRAPH_LOOPS_TWICE: ( 0 2 2 3 ) Graph with 2 edges from 0 to 1, and 2 from 1 to 0, IGRAPH_ALL, IGRAPH_MULTIPLE: ( 1 3 0 2 ) Graph with 1 edge from 0 to 1, and 2 from 1 to 0, IGRAPH_ALL, IGRAPH_MULTIPLE: ( 0 2 1 ) Trying IGRAPH_LOOPS_TWICE with IGRAPH_OUT: Vertex not in graph: Non-existent mode: