brainconn.core.kcore_bd

kcore_bd(CIJ, k, peel=False)

The k-core is the largest subnetwork comprising nodes of degree at least k. This function computes the k-core for a given binary directed connection matrix by recursively peeling off nodes with degree lower than k, until no such nodes remain.

Parameters:

• CIJ (NxN numpy.ndarray) – binary directed adjacency matrix
• k (int) – level of k-core
• peel (bool) – If True, additionally calculates peelorder and peellevel. Defaults to False.

Returns:

• CIJkcore (NxN numpy.ndarray) – connection matrix of the k-core. This matrix only contains nodes of degree at least k.
• kn (int) – size of k-core
• peelorder (Nx1 numpy.ndarray) – indices in the order in which they were peeled away during k-core decomposition. only returned if peel is specified.
• peellevel (Nx1 numpy.ndarray) – corresponding level - nodes in at the same level have been peeled away at the same time. only return if peel is specified

Notes

‘peelorder’ and ‘peellevel’ are similar the the k-core sub-shells described in Modha and Singh (2010).