Function vertex_path_from_edge_path 

pub fn vertex_path_from_edge_path(
    graph: &Graph,
    start: Option<u32>,
    edge_path: &[u32],
    mode: WalkMode,
) -> IgraphResult<Vec<u32>>

Convert an edge path to a vertex path.

Given a sequence of edge IDs forming a continuous walk starting at start, returns the sequence of vertex IDs traversed. The result always has edge_path.len() + 1 elements.

If start is None, the start vertex is inferred from the first edge (requires at least one edge). For directed graphs with WalkMode::Out, the source of the first edge is used; for In, the target is used. For undirected graphs or All mode with multiple edges, the vertex connecting the first two edges is determined.

The mode parameter is ignored for undirected graphs (treated as All).

Errors

• InvalidArgument if start is out of range.
• InvalidArgument if start is None and edge_path is empty.
• InvalidArgument if the edge IDs do not form a continuous path.

Examples

use rust_igraph::{Graph, vertex_path_from_edge_path, WalkMode};

let mut g = Graph::with_vertices(4);
g.add_edge(0, 1).unwrap(); // eid 0
g.add_edge(1, 2).unwrap(); // eid 1
g.add_edge(2, 3).unwrap(); // eid 2

let vpath = vertex_path_from_edge_path(&g, Some(0), &[0, 1, 2], WalkMode::All).unwrap();
assert_eq!(vpath, vec![0, 1, 2, 3]);