I have 2 buckets.

Each bucket holds documents.

Each document has a vector field.

I want to measure the distance between them.

To measure the distance, I need to **take the mean vector out of each bucket** , and calculate the delta between them.

What the best way to save the vectors ( `knn_vector`

? spread the vector to discrete field `x0`

, `x1`

, `x2`

?) and perform the calculation of the mean vector? (Painless script that iterates the vector, save in the state the sum of each dimension and calculate the average in the `reduce_script`

?)