GSP - Gap, Window

MBM

Hey all, 

 

does anybody have a tip on how to set the parameters correctly in the GSP-Operator? 

What does windwow and Gap (min/max) exactely mean? Or has anybody good literature where it is explained? It cannot be so hard to explain it in max 5 sentences if someone knows how it works. 

 

Best wishes

Marcel

jwpfau

min gap

Minimal timespan between two transactions

max gap

Maximal timespan between two transactions

window size

Transactions inside this timespan are also seen as a single transaction

min support

Percentage of sequences that must contain a pattern

If you use window size, it might make sense to also define a min gap with the same value, so that all transactions in this timespan only appear as the single merged transaction. With the min support you should start as high as possible (0,9x) and slowly work down, otherwise the algorithm will generate too many combinations and run forever.