apache spark - How to compute the average vector of a set of vectors in scala? -

i have rdd of form

(3,compactbuffer((-0.063763,0.060122,0.250393), (0.006971,-0.096478,0.123718), (-0.198281,-0.079444,-0.015460))) 

i need calculate average of vectors in compactbuffer

val averagevector = filteredvectors.reduce((a,b) => sum(b)/b.size) 

by doing reduce action 1 shown above.

my averagevector should (3, (avg(1), avg(2), avg(3))) avg(1) average of first elements in compactbuffer shown above.