affinity {arules} | R Documentation |
Provides the generic function affinity
and the S4 methods
to compute and return a similarity matrix with the affinities between items
for a set of transactions
.
affinity(x)
x |
a matrix or an object of class |
Affinity between the two items i and j is defined by Aggarwal et al. (2002) as
A(i,j) = sup({i,j})/(sup({i}) + sup({j}) - sup({i,j})),
where sup(.) is the support measure. This means that affinity is the Jaccard similarity between items.
returns an object of class ar_similarity
which represents
the affinities between items in x
.
Michael Hahsler
Charu C. Aggarwal, Cecilia Procopiuc, and Philip S. Yu (2002) Finding localized associations in market basket data, IEEE Trans. on Knowledge and Data Engineering, 14(1):51–62.
dissimilarity
,
ar_similarity-class
,
itemMatrix-class
data("Adult") ## choose a sample, calculate affinities s <- sample(Adult, 500) s a <- affinity(s) image(a)