clevr (version 0.1.2)

clusters_to_membership: Transform Clustering Representations

Description

Transform between different representations of a clustering.

Usage

clusters_to_membership(clusters, elem_ids = NULL, clust_ids = NULL)
membership_to_clusters(membership, elem_ids = NULL, clust_ids = NULL)
clusters_to_pairs(clusters)
membership_to_pairs(membership, elem_ids = NULL)
pairs_to_membership(pairs, elem_ids)
pairs_to_clusters(pairs, elem_ids)

Value

clusters_to_membership and pairs_to_membership both return a membership vector representation of the clustering. The order of the elements is taken from elem_ids if specified, otherwise the elements are ordered lexicographically by their identifiers. For pairs_to_membership, the cluster identifiers cannot be recovered and are taken to be integers.

membership_to_clusters and pairs_to_clusters both return a representation of the clustering as a list of vectors. The order of the clusters is taken from clust_ids if specified, otherwise the clusters are ordered lexicographically by their identifiers. For pairs_to_clusters, the cluster identifiers cannot be recovered and are taken to be integers.

clusters_to_pairs and membership_to_pairs both return a representation of the clustering as a matrix of element pairs that are co-clustered. This representation results in loss of information, as singleton clusters (with one element) and cluster identifiers are not represented.

Arguments

clusters

a representation of a clustering as a list of vectors, where the i-th vector contains the identifiers of elements assigned to the i-th cluster. If clust_ids is specified (see below), the i-th cluster is identified according to the corresponding entry in clust_ids. Otherwise the i-th cluster is identified according it's name (if clusters is a named list) or its integer index i.

elem_ids

a vector specifying the complete set of identifiers for the cluster elements in canonical order. Optional for all functions excluding pairs_to_membership and pairs_to_clusters.

clust_ids

a vector specifying the complete set of identifiers for the clusters in canonical order. Optional for all functions.

membership

a representation of a clustering as a membership vector, where the i-th entry contains the cluster identifier for the i-th element. If elem_ids is specified (see below), the i-th element is identified according to the corresponding entry in elem_ids. Otherwise the i-th element is identified according it's name (if members is a named vector) or its integer index i.

pairs

a representation of a clustering as a matrix or data.frame containing all pairs of elements that are co-clustered. The rows index of the matrix/data.frame index pairs and columns index the identifiers of the constituent elements. The elem_ids argument (see below) must be specified in order to recover singleton clusters (containing a single element).

Examples

## A clustering of three items represented as a membership vector
m <- c("Item1" = 1, "Item2" = 2, "Item3" = 1)

# Transform to list of clusters
membership_to_clusters(m)
# Specify different identifiers for the items
membership_to_clusters(m, elem_ids = c(1, 2, 3))
# Transform to array of pairs that are co-clustered
membership_to_pairs(m)

## A clustering represented as a list of clusters
cl <- list("ClustA" = c(1,3), "ClustB" = c(2))

# Transform to membership vector representation
clusters_to_membership(cl)
# Transform to array of pairs that are co-clustered
clusters_to_pairs(cl)

## A clustering (incompletely) represented as an array of pairs that
## are co-clustered
p <- rbind(c(1,3)) # pairs of elements in the same cluster
ids <- c(1,2,3)    # necessary to specify set of all elements

# Transform to membership vector representation
pairs_to_membership(p, ids)
# Transform to list of clusters
pairs_to_clusters(p, ids)