[igraph] problem about calculating closeness centrality

[镜]

Hi

The igraph vesion I was using is 6.5,and I have a problem about calculating closeness centrality.When I use the function like this

igraph_vector_t  v_closeness;

igraph_vector_init(&v_closeness, 0);

‍graph_closeness(&g, &v_closeness, igraph_vss_all(), IGRAPH_ALL, 0);

the result in v_closeness is zero.

The parameters' meaning are as follows:‍‍

&g means the graph data ;

&v_closeness is used to store the result;

the graph is undirected and unweighted;

I want to calculate all vertices in the graph.In this function I can't get the right result ,and I don't know why.Maybe I need your help.

Thank you very much!

Best Regrads!

Tian Li