I have two numpy arrays which look like this:

```
x = [v1, v2, v3, ..., vm]
y = [w1, w2, w3, ..., wn]

```

where `vi, wj` are numpy arrays of length 3.

I want to perform a pairwise *summation* of v's and w's and get a final array

```
z = [v1+w1, v1+w2,...,v1+wn,v2+w1, ..., vi+wj, ..., vm+wn]

```

A simple way of obtaining `z` is as follows:

```
z = np.zeros ((m*n, 3))
for i in range(m):
    for j in range(n):
        z[n*i+j] = x[i] + y[j] 

```

This computation is not feasible is `m, n` are very large.

I know scipy.spatial has methods to enumerate pairwise distances using distance\_matrix in a vectorized fashion.

I want to ask if there is a vectorized version of performing such pairwise *additions* for numpy arrays?