8.1.2. sklearn.cluster.DBSCAN

class sklearn.cluster.DBSCAN(eps=0.5, min_samples=5, metric='euclidean', verbose=False, random_state=None)

Perform DBSCAN clustering from vector array or distance matrix.

DBSCAN - Density-Based Spatial Clustering of Applications with Noise. Finds core samples of high density and expands clusters from them. Good for data which contains clusters of similar density.

Parameters :

eps : float, optional

The maximum distance between two samples for them to be considered as in the same neighborhood.

min_samples : int, optional

The number of samples in a neighborhood for a point to be considered as a core point.

metric : string, or callable

The metric to use when calculating distance between instances in a feature array. If metric is a string or callable, it must be one of the options allowed by metrics.pairwise.calculate_distance for its metric parameter. If metric is “precomputed”, X is assumed to be a distance matrix and must be square.

random_state : numpy.RandomState, optional

The generator used to initialize the centers. Defaults to numpy.random.

verbose : boolean, optional

The verbosity level

Notes

See examples/plot_dbscan.py for an example.

References: Ester, M., H. P. Kriegel, J. Sander, and X. Xu, “A Density-Based Algorithm for Discovering Clusters in Large Spatial Databases with Noise”. In: Proceedings of the 2nd International Conference on Knowledge Discovery and Data Mining, Portland, OR, AAAI Press, pp. 226–231. 1996

Attributes

core_sample_indices_	array, shape = [n_core_samples]	Indices of core samples.
components_	array, shape = [n_core_samples, n_features]	Copy of each core sample found by training.
labels_	array, shape = [n_samples]	Cluster labels for each point in the dataset given to fit(). Noisy samples are given the label -1.

Methods

fit(X, **params)	Perform DBSCAN clustering from vector array or distance matrix.
set_params(**params)	Set the parameters of the estimator.

__init__(eps=0.5, min_samples=5, metric='euclidean', verbose=False, random_state=None)

fit(X, **params)

Perform DBSCAN clustering from vector array or distance matrix.

Parameters :

X: array [n_samples, n_samples] or [n_samples, n_features] :

Array of distances between samples, or a feature array. The array is treated as a feature array unless the metric is given as ‘precomputed’.

params: dict :

Overwrite keywords from __init__.

set_params(**params)

Set the parameters of the estimator.

The method works on simple estimators as well as on nested objects (such as pipelines). The former have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Returns :self :