Re: Difference between "Forward/Backward extension checking" and "Closure jumping"
Date: February 07, 2020 08:51PM
Hi,
You have understand the main idea about forward/backward checking.
For closure jumping, the idea is not complicated. It is as follows. Let say that you have this database:
A B C D F
A C D F
A C D E F
A E
You can count the support of the items:
A = 4
B = 1
C = 3
D = 3
E = 2
F = 3
Since C, D and F have the same support, it means that they always appears together, and thus we can directly say that {C,D,F} is a closed itemset. It is unecessary to check the itemset {CD} {DF} and {CF} because they will not be closed. So using this technique we "jump" directly to {C,D,F} and output it as a closed itemset which will save some time.
You can apply this technique on the input database or in any projected database.
Best regards,
Philippe
Edited 2 time(s). Last edit at 02/07/2020 08:52PM by webmasterphilfv.