Maybe it's easiest to give an example. If you have input:
a b c a b c d a c d a b c You should expect Mahout to output (say, for support 2): [a, b, c],3 [a, c, d],2 [a, c],4 You might also expect to see [a],4 or [a, b],3 but these are implied by the other patterns. Note that [a, b] and [a, c] are both subpatterns of [a, b, c]. Only [a, c] is emitted because it has greater support than [a, b, c]; [a, b] is not emitted, since it has support equal to a reported superpattern. If you were to create all possible subsets of each output pattern (with the same support as the generating pattern), then dedup these by taking max-support, you'd have" fully-verbose" results. Currently there is no trivial way to disable this behavior; it would require code changes. I'm not sure how easy it would be in the current code, but I think it'd be reasonably easy in an alternate implementation I've been trying to contribute. -tom On Mon, Dec 19, 2011 at 6:34 AM, gaurav singh <[email protected]> wrote: > That seems to make sense. What do you mean by " Mahout will not report any > of those unless the support is strictly greater > than 3. " Is there a way for me to get all the patterns with support > strictly greater then a particular value? > > Thanks > Gaurav > > On Mon, Dec 19, 2011 at 4:58 PM, Tom Pierce <[email protected]> wrote: > >> One possible explanation is that Mahout's FPG avoids reporting >> patterns that are subsumed by others. >> >> For example, if you have pattern [a, b, c] with support 3, you clearly >> must also have [a, b], [b, c] and [a, c] with support >= 3. Mahout >> will not report any of those unless the support is strictly greater >> than 3. >> >> Does that help explain your discrepancies? If not can you share an >> example data set along with a missed pattern? >> >> -tom >> >> On Mon, Dec 19, 2011 at 1:37 AM, gaurav singh <[email protected]> >> wrote: >> > Hi All, >> > >> > I am using mahout on Ubuntu 10.04 from the repository and running it >> on a >> > data set of 1472 row, I am running it in sequential mode with k=200,000 >> and >> > s= 400. I have implemented fp-growth in php but when I compare the output >> > of my implementation of fp-growth and mahout fpg, I find that in mahout >> the >> > output consists of just 17,500 patterns whereas from my implementation I >> > get around 65,000 unique patterns(I have verified there uniqueness!), for >> > the same value of support threshold. I have also verified my outputs from >> > the actual data set and have found out that all my patterns are correct >> and >> > do exist in the data set with correct value of their support. >> > >> > >> > Can anyone please explain me the reason?? >> > >> > Thanks!! >> > >> > -- >> > regards >> > Gaurav Singh >> > >> > >> > >> > >> > >> > -- >> > regards >> > Gaurav Singh >> > >> > >> > >> > >> > >> > -- >> > regards >> > Gaurav Singh >> > > > > -- > regards > Gaurav Singh
