An Efficient Algorithm for Deriving Frequent Itemsets from Lossless Condensed Representation

Mining frequent itemsets (abbr. FIs) from dense databases usually generates a large amount of itemsets, causing the mining algorithms to suffer from long execution time and high memory usage. Frequent closed itemset (abbr. FCI) is a lossless condensed representation of FI. Mining only the FCIs allows to reducing the execution time and memory usage. Moreover, with correct methods, the complete information of FIs can be derived from FCIs. Although many studies have presented various efficient approaches for mining FCIs, few of them have developed efficient algorithms for deriving FIs from FCIs. In view of this, we propose a novel algorithm called DFI-Growth for efficiently deriving FIs from FCIs. Moreover, we propose two strategies, named maximum support selection and maximum support replacement to guarantee that all the FIs and their supports can be correctly derived by DFI-Growth. To the best of our knowledge, the proposed DFI-Growth is the first kind of tree-based and pattern growth algorithm for deriving FIs from FCIs. Experiments show that DFI-Growth is superior to the most advanced deriving algorithm [12] in terms of both execution time and memory consumption.