Connected Components

`navis_fastcore.connected_components(node_ids, parent_ids)`

Get the connected components for this neuron.

PARAMETER	DESCRIPTION
`node_ids`	`Array of node IDs.` TYPE: `(N, ) array`
`parent_ids`	`Array of parent IDs for each node. Root nodes' parents must be -1.` TYPE: `(N, ) array`

RETURNS	DESCRIPTION
`cc`	For each node the node ID of its root (= connected component ID). TYPE: `(N, ) int32 array`

Examples:

Fully connected neuron:

>>> import navis_fastcore as fastcore
>>> import numpy as np
>>> node_ids = np.arange(7)
>>> parent_ids = np.array([-1, 0, 1, 2, 1, 4, 5])
>>> fastcore.connected_components(node_ids, parent_ids)
array([0, 0, 0, 0, 0, 0, 0])

Introduce a break:

>>> parent_ids[4] = -1
>>> fastcore.connected_components(node_ids, parent_ids)
array([0, 0, 0, 0, 4, 4, 4])