nltk_lite.cluster.VectorSpace

Package nltk_lite :: Package cluster :: Class VectorSpace

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Class VectorSpace

ClusterI --+
           |
          VectorSpace

Known Subclasses:: EM, GroupAverageAgglomerative, KMeans

Abstract clusterer which takes tokens and maps them into a vector space. Optionally performs singular value decomposition to reduce the dimensionality.

Method Summary
	`__init__(self, normalise, svd_dimensions)`
	`classify(self, vector)`
	`classify_vectorspace(self, vector)` Returns the index of the appropriate cluster for the vector.
	`cluster(self, vectors, assign_clusters)` Assigns the vectors to clusters, learning the clustering parameters from the data.
	`cluster_vectorspace(self, vectors, trace)` Finds the clusters using the given set of vectors.
	`likelihood(self, vector, label)` Returns the likelihood (a float) of the token having the corresponding cluster.
	`likelihood_vectorspace(self, vector, cluster)` Returns the likelihood of the vector belonging to the cluster.
	`vector(self, vector)` Returns the vector after normalisation and dimensionality reduction
	`_normalise(self, vector)` Normalises the vector to unit length.
Inherited from `ClusterI`: `classification_probdist`, `cluster_name`, `cluster_names`, `num_clusters`

Method Details

init(self, normalise=False, svd_dimensions=None)
(Constructor)

Parameters:: normalise - should vectors be normalised to length 1
(type=boolean); svd_dimensions - number of dimensions to use in reducing vector dimensionsionality with SVD
(type=int)

classify_vectorspace(self, vector)

Returns the index of the appropriate cluster for the vector.

cluster(self, vectors, assign_clusters=False, trace=False)

Assigns the vectors to clusters, learning the clustering parameters from the data. Returns a cluster identifier for each vector.

Overrides:: nltk_lite.cluster.ClusterI.cluster (inherited documentation)

cluster_vectorspace(self, vectors, trace)

Finds the clusters using the given set of vectors.

likelihood(self, vector, label)

Returns the likelihood (a float) of the token having the corresponding cluster.

Overrides:: nltk_lite.cluster.ClusterI.likelihood (inherited documentation)

likelihood_vectorspace(self, vector, cluster)

Returns the likelihood of the vector belonging to the cluster.

vector(self, vector)

Returns the vector after normalisation and dimensionality reduction

_normalise(self, vector)

Normalises the vector to unit length.

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