PTP algorithm uses filtering mechanism to reduce the size of projected trees, and therefore it saves the time of building projected trees and increases the performance of mining.

• 为了避免过多非频繁的分支建立，因此PTP演算法在此用了过滤机制用来减小产生的投影树，这样不但能加快建树时间，探勘时的速度也会明显变快。