Partitioning Around Medoids Object
- DESCRIPTION:
-
These are objects of class
"pam"
They represent a partitioning of a dataset into clusters.
- GENERATION:
-
This class of objects is returned from pam.
- METHODS:
-
The "pam" class has methods for the following generic functions:
print, summary.
- INHERITANCE:
-
The class "pam" inherits from "partition".
By that, the generic function plot can be used with a pam object.
- STRUCTURE:
-
A legitimate pam object is a list with the following components:
- medoids:
-
the medoids or representative objects of the clusters. If a dissimilarity
matrix was given as input to pam, then a vector of numbers or labels of
objects is given, else medoids is a matrix with in each row the
coordinates of one medoid.
- clustering:
-
the clustering vector. A vector with length equal to the number of objects,
giving the number of the cluster to which each object belongs.
- objective:
-
the objective function after the first and second step of the pam
algorithm.
- clusinfo:
-
matrix, each row gives numerical information for one cluster. These are
the cardinality of the cluster (number of objects), the maximal and average
dissimilarity between the objects in the cluster and the cluster's medoid,
the diameter of the cluster (maximal dissimilarity between two objects of
the cluster), and the separation of the cluster (minimal dissimilarity
between an object of the cluster and an object of another cluster).
- isolation:
-
vector with length equal to the number of clusters, specifying which
clusters are isolated clusters (L- or L*-clusters) and which clusters are
not isolated.
A cluster is an L*-cluster iff its diameter is smaller than its separation.
A cluster is an L-cluster iff for each object i the maximal dissimilarity
between i and any other object of the cluster is smaller than the minimal
dissimilarity between i and any object of another cluster.
Clearly each L*-cluster is also an L-cluster.
- silinfo:
-
list with all information necessary to construct a silhouette plot of the
clustering.
The first component is a matrix, with for each object i the cluster to which
i belongs, as well as the neighbor cluster of i (the cluster, not containing
i, for which the average dissimilarity between its objects and i is
minimal), and the silhouette width of i.
The other two components give the average silhouette width per cluster and
the average silhouette width for the dataset.
See plot.partition for more information.
- diss:
-
an object of class "dissimilarity", representing the total dissimilarity
matrix of the dataset.
- SEE ALSO:
-
dissimilarity.object
,
pam
,
partition.object
,
plot.partition
.