Computing Affinity Between Items
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.
data("Adult")
## choose a sample, calculate affinities
s <- sample(Adult, 500)
s
a <- affinity(s)
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