Sample from tensor given batch of 2D coords

[mureva]

Hi,

I have a tensor (batches, a, b, 2, rows, cols) which is basically a bunch of pairs of (rows,cols) images - so let's simplify and say that I have a pair of images in a tensor A of shape (2, rows, cols).

It just so happens that this pair of images represents a coordinate (y,x), and I want to sample from a second tensor B at that coordinate.
coord = (y,x) = ( A[0,v,u], A[1,v,u] )

Is there a Symbol operator that will let me create C = sample( B , A ) such that each pixel C[:,v,u] comes from the relevant pixel B[:,y,x] given the coordinate in A

I was thinking that gather_nd would maybe be the right choice, but I'm getting hopelessly confused trying to feed my coordinates to it.

Keep in mind please that I'm really wanting to do this for a batch of pairs of images - and I'm in C++ (hence using Symbol)