Yep. That is a problem. Emit a constant key and a pair containing an integer and a vector. Add them up separately. Divide at the end. The initial value for the integer from the mapper should be 1.
On Thu, Apr 28, 2011 at 8:26 PM, Vckay <[email protected]> wrote: > However, the problem that I can see is that the > reducer wont know the number of values that were aggregated by combiner > which is needed for it to compute the mean. >
