Improved Strategy for High-Utility Pattern Mining Algorithm
Algorithm 2
The search procedure.
Input: α: an itemset; α-D: the α projected database; Primary(α): the primary items of α; Secondary(α): the secondary items of α; MinU: a user-specified threshold.
Output: the set of high-utility itemsets that are extensions of α
(1)
for each item i ∈ Primary(α) do
(2)
β = α∪{i};
(3)
Scan α−D to calculate u(β) and create β−D//uses transaction merging;
(4)
if u(β) ≥ MinU then output β;
(5)
Calculate su(β,z) and lu(β,z) for all item z ∈ Secondary(α) by scanning β−D once, using two utility-bin arrays;
(6)
Primary(β) = {z ∈ Secondary(α)|su(β,z) ≥MinU };
(7)
Secondary(β) = {z ∈ Secondary(α)|lu(β,z) ≥ MinU };
