int main() {
igraph_t g;
igraph_vector_t v, weights;
long int i;
igraph_real_t value;
igraph_arpack_options_t options;
igraph_star(&g, 100, IGRAPH_STAR_UNDIRECTED, 0);
igraph_arpack_options_init(&options);
igraph_vector_init(&v, 0);
igraph_eigenvector_centrality(&g, &v, &value, /*directed=*/ 0,
/*scale=*/0, /*weights=*/0,
&options);
if (options.info != 0) {
return 1;
}
for (i=0; i<igraph_vector_size(&v); i++) {
printf(" %.3f", fabs(VECTOR(v)[i]));
}
printf("\n");
igraph_destroy(&g);
/* Special cases: check for empty graph */
igraph_empty(&g, 10, 0);
igraph_eigenvector_centrality(&g, &v, &value, 0, 0, 0, &options);
if (value != 0.0) {
return 1;
}
for (i=0; i<igraph_vector_size(&v); i++) {
printf(" %.2f", fabs(VECTOR(v)[i]));
}
printf("\n");
igraph_destroy(&g);
/* Special cases: check for full graph, zero weights */
igraph_full(&g, 10, 0, 0);
igraph_vector_init(&weights, 45);
igraph_vector_fill(&weights, 0);
igraph_eigenvector_centrality(&g, &v, &value, 0, 0, &weights, &options);
igraph_vector_destroy(&weights);
if (value != 0.0) {
return 2;
}
for (i=0; i<igraph_vector_size(&v); i++) {
printf(" %.2f", fabs(VECTOR(v)[i]));
}
printf("\n");
igraph_destroy(&g);
igraph_vector_destroy(&v);
return 0;
}
/* call-seq:
* graph.eigenvector_centrality(scale, weights) -> Array
*
* Returns a two-element arrar, the first element of which is an Array of
* eigenvector centrality scores for graph, and the second of which is the
* eigenvalue.
*
* scale is a boolean value. If true, the scores will be weighted so that the
* absolute value of the maximum centrality is one.
*
* weights is an Array giving the weights of the edges. If nil, the edges are unweighted.
*/
VALUE cIGraph_eigenvector_centrality(VALUE self, VALUE scale, VALUE weights) {
int i;
igraph_t *graph;
igraph_vector_t vec;
igraph_real_t val;
igraph_vector_t wgts;
igraph_arpack_options_t arpack_opt;
igraph_bool_t sc = 0;
VALUE eigenvector = rb_ary_new();
VALUE rb_res = rb_ary_new();
IGRAPH_FINALLY(igraph_vector_destroy, &vec);
IGRAPH_FINALLY(igraph_vector_destroy, &wgts);
IGRAPH_CHECK(igraph_vector_init(&vec,0));
IGRAPH_CHECK(igraph_vector_init(&wgts,0));
igraph_arpack_options_init(&arpack_opt);
if (scale == Qtrue) sc = 1;
Data_Get_Struct(self, igraph_t, graph);
if (weights == Qnil) {
IGRAPH_CHECK(igraph_eigenvector_centrality(graph, &vec, &val, sc, NULL, &arpack_opt));
} else {
for(i = 0; i < RARRAY_LEN(weights); i++)
IGRAPH_CHECK(igraph_vector_push_back(&wgts, NUM2DBL(RARRAY_PTR(weights)[i])));
IGRAPH_CHECK(igraph_eigenvector_centrality(graph, &vec, &val, sc, &wgts, &arpack_opt));
}
for(i = 0; i < igraph_vector_size(&vec); i++)
rb_ary_push(eigenvector, rb_float_new(VECTOR(vec)[i]));
igraph_vector_destroy(&vec);
igraph_vector_destroy(&wgts);
rb_ary_push(rb_res, eigenvector);
rb_ary_push(rb_res, rb_float_new(val));
IGRAPH_FINALLY_CLEAN(2);
return rb_res;
}
