Function reciprocal_degree_distance 

pub fn reciprocal_degree_distance(graph: &Graph) -> IgraphResult<f64>

Compute the reciprocal degree distance (additively weighted Harary index).

RDD(G) = Σ_{u<v, dist(u,v)<∞} [d(u) + d(v)] / dist(u,v)

Disconnected pairs (infinite distance) are skipped.

Examples

use rust_igraph::{Graph, reciprocal_degree_distance};

// Path 0-1-2: d=[1,2,1]
// (0,1): (1+2)/1=3, (0,2): (1+1)/2=1, (1,2): (2+1)/1=3
// RDD = 7
let g = Graph::from_edges(&[(0,1),(1,2)], false, Some(3)).unwrap();
assert!((reciprocal_degree_distance(&g).unwrap() - 7.0).abs() < 1e-10);