[igraph] vertex ids and function igraph_vcount(const igraph_t *graph)

[Christian Gonzalez]

Hello everybody
    if you have a graph with six edges like this:


...
igraph_t graph;
igraph_vector_t edges;

...

igraph_vector_init(&edges, 6);

...

VECTOR(edges)[0] = 1200000
VECTOR(edges)[1] = 1200001
VECTOR(edges)[2] = 846
VECTOR(edges)[3] = 30000000
VECTOR(edges)[4] = 1200001
VECTOR(edges)[5] = 846

...

igraph_create(&graph, &edges, 0, IGRAPH_DIRECTED)



How many memory is reserved for the vertex vector? --> 4 or 30000000 
positions?
because if you call function  igraph_vcount(&graph), the return is 
30000000 instead of 4.

Why this functions returns the maximum vertex id? instead of the number 
of vertex in the graph


Regards,
Christian