arules (version 0.4-2)

is.maximal: Find Maximal Itemsets

Description

Provides the generic function and the S4 method is.maximal for finding maximal itemsets. An itemset is maximal in a set if no proper superset of the itemset is contained in the set (Zaki et al., 1997).

Usage

is.maximal(x,...)
## S3 method for class 'itemMatrix':
is.maximal(x, blocksize = 200)

Arguments

x

the set of itemsets or an itemMatrix object.

...

further arguments.

blocksize

"numeric"; how much memory can is.maximal use for large x (approx. in MB). This is only a crude approximation for 32-bit machines (64-bit architectures need double the blocksize in memory).

Value

• a logical vector with the same length as x indicating for each element in x if it is a maximal itemset.

Details

Note that the method uses is.superset which can be extremely slow and have a high memory usage for x containing many elements.

References

Mohammed J. Zaki, Srinivasan Parthasarathy, Mitsunori Ogihara, and Wei Li (1997): New algorithms for fast discovery of association rules. Technical Report 651, Computer Science Department, University of Rochester, Rochester, NY 14627.

See Also

is.superset, itemMatrix-class, itemsets-class