affinity_to_edge_index¶

tiatoolbox . tools . graph . affinity_to_edge_index

affinity_to_edge_index(affinity_matrix, threshold=0.5)[source]¶

Convert an affinity matrix (similarity matrix) to an edge index.

Converts an NxN affinity matrix to a 2xM edge index, where M is the number of node pairs with a similarity greater than the threshold value (defaults to 0.5).

Parameters:

affinity_matrix (torch.Tensor | np.ndarray) – An NxN matrix of affinities between nodes.
threshold (Number) – Threshold above which to be considered connected. Defaults to 0.5.

Returns:

The edge index of shape (2, M).

Return type:

torch.Tensor | np.ndarray

Example

>>> rng = np.random.default_rng()
>>> points = rng.random((100, 2))
>>> adjacency = delaunay_adjacency(points)
>>> edge_index = affinity_to_edge_index(adjacency)