An Improved Apriori Algorithm Based on an Evolution-Communication Tissue-Like P System with Promoters and Inhibitors

Algorithm 1

ECTP-Apriori algorithm.

Input:

 The objects encoded from the transactional database and objects representing the support count

 threshold .

 Rule :

 Copy all and to cells 1 to .

Method:

 Rule :

 Generate for to form the candidate frequent 1-itemsets .

 Rule :

 Scan each object in cell 1 to count the frequency of each item. If is in cell 1, consume one and

 generate one . Continue until all copies of have been consumed or all objects have been scanned.

 Rule :

 If all copies of have been consumed, generate an object to add to as a frequent 1-itemset

 and pass to cells 2 and . Delete all remaining copies of and delete all copies of .

For ( and ) do the following in cell :

 Rule :

 Scan the objects representing the frequent ()-itemsets to generate the objects

 representing the candidate frequent -itemsets .

 Rule :

 Delete all objects after they have been used by rule .

 Rule :

 Scan the objects representing the database to count the frequency of each candidate frequent -itemset

  . If the objects and are all in cell , consume one and generate one .

  Continue until all copies of have been consumed or all objects have been scanned.

 Rule :

 If all copies of have been consumed, generate to add to as a frequent

 -itemset and put in cells and . Delete all remaining copies of and delete all copies

 of .

 Let .

Output:

 The collection of all frequent itemsets encoded by objects .