sklearn.cluster.Ward

class sklearn.cluster.Ward(n_clusters=2, memory=Memory(cachedir=None), connectivity=None, n_components=None, compute_full_tree='auto', pooling_func=<function mean at 0x1c58cf8>)[source]

Ward hierarchical clustering: constructs a tree and cuts it.

Recursively merges the pair of clusters that minimally increases within-cluster variance.

Parameters:

n_clusters : int or ndarray

The number of clusters to find.

connectivity : sparse matrix (optional)

Connectivity matrix. Defines for each sample the neighboring samples following a given structure of the data. Default is None, i.e, the hierarchical clustering algorithm is unstructured.

memory : Instance of joblib.Memory or string (optional)

Used to cache the output of the computation of the tree. By default, no caching is done. If a string is given, it is the path to the caching directory.

n_components : int (optional)

The number of connected components in the graph defined by the connectivity matrix. If not set, it is estimated.

compute_full_tree : bool or ‘auto’ (optional)

Stop early the construction of the tree at n_clusters. This is useful to decrease computation time if the number of clusters is not small compared to the number of samples. This option is useful only when specifying a connectivity matrix. Note also that when varying the number of clusters and using caching, it may be advantageous to compute the full tree.

Attributes:

labels_ : array [n_features]

cluster labels for each feature

n_leaves_ : int

Number of leaves in the hierarchical tree.

n_components_ : int

The estimated number of connected components in the graph.

children_ : array-like, shape (n_nodes-1, 2)

The children of each non-leaf node. Values less than n_samples refer to leaves of the tree. A greater value i indicates a node with children children_[i - n_samples].

See also

AgglomerativeClustering
agglomerative hierarchical clustering

Methods

__init__(n_clusters=2, memory=Memory(cachedir=None), connectivity=None, n_components=None, compute_full_tree='auto', pooling_func=<function mean at 0x1c58cf8>)[source]
fit(X, y=None)[source]

Fit the hierarchical clustering on the data

Parameters:

X : array-like, shape = [n_samples, n_features]

The samples a.k.a. observations.

Returns:

self :

fit_predict(X, y=None)[source]

Performs clustering on X and returns cluster labels.

Parameters:

X : ndarray, shape (n_samples, n_features)

Input data.

Returns:

y : ndarray, shape (n_samples,)

cluster labels

get_params(deep=True)[source]

Get parameters for this estimator.

Parameters:

deep: boolean, optional :

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns:

params : mapping of string to any

Parameter names mapped to their values.

set_params(**params)[source]

Set the parameters of this 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 :