Function layout_align 

pub fn layout_align(graph: &Graph, layout: &mut [Vec<f64>]) -> IgraphResult<()>

Align a graph layout with the coordinate axes.

Centers vertex positions on the origin and rotates them so that the layout’s principal axes (computed from the nematic tensor of edge directions) coincide with the coordinate axes. After rotation, axes are reordered so the widest extent is in column 0.

The layout is modified in place. Each inner Vec represents one vertex’s coordinates; all must have the same length (dim ≥ 1).

Errors

Returns InvalidArgument if:

• layout.len() does not equal graph.vcount().
• Any coordinate vector differs in length from the first.
• dim == 0 (zero-dimensional coordinates).

Examples

use rust_igraph::{Graph, layout_align};

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

// Arbitrary 2D positions
let mut layout = vec![vec![1.0, 2.0], vec![3.0, 4.0], vec![5.0, 6.0]];
layout_align(&g, &mut layout).unwrap();

// After alignment, the center of mass is at the origin
let cx: f64 = layout.iter().map(|p| p[0]).sum::<f64>() / 3.0;
let cy: f64 = layout.iter().map(|p| p[1]).sum::<f64>() / 3.0;
assert!((cx).abs() < 1e-10);
assert!((cy).abs() < 1e-10);