It sounds pretty undefined, but I would tend to define the distance as 0 in this case of course. And that means defining the cosine as 1. Which class in particular? There are a few implementations of this distance measure.
On Thu, Apr 4, 2013 at 7:42 PM, Dan Filimon <dangeorge.fili...@gmail.com> wrote: > In the case where both vectors are all zeros, the angle between them is 0, > so the cosine is therefore 1 and the so the distance returned should be 0 > (unless I misunderstood what the distance does). > > In Mahout, when calling distance() however, if both the denominator and > dotProduct are 0 (which is true when both vectors are 0), the returned > value is 1. > > This looks like a bug to me and I would open a JIRA issue and fix it but I > want to make sure there's nothing I could possibly be missing. > > Thoughts?
