Source code for sknetwork.utils.membership

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
Created on July 10, 2019
@author: Nathan de Lara <>
@author: Thomas Bonald <>
from typing import Optional

import numpy as np
from scipy import sparse

[docs]def membership_matrix(labels: np.ndarray, dtype=bool, n_labels: Optional[int] = None) -> sparse.csr_matrix: """Build a n x k matrix of the label assignments, with k the number of labels. Negative labels are ignored. Parameters ---------- labels : Label of each node. dtype : Type of the entries. Boolean by default. n_labels : int Number of labels. Returns ------- membership : sparse.csr_matrix Binary matrix of label assignments. Notes ----- The inverse operation is simply ``labels = membership.indices``. """ n: int = len(labels) if n_labels is None: shape = (n, max(labels)+1) else: shape = (n, n_labels) ix = (labels >= 0) data = np.ones(ix.sum()) row = np.arange(n)[ix] col = labels[ix] return sparse.csr_matrix((data, (row, col)), shape=shape, dtype=dtype)