fptree
Builds a FP-tree.
Return
the FP-tree.
Parameters
supplier
the lambda to retrun a stream of item set database. Each item set may have different length. The item identifiers have to be in [0, n), where n is the number of items. Item set should NOT contain duplicated items. Note that it is reordered after the call.
min Support
the required minimum support of item sets in terms of frequency.