Compute a spatial gradient field along each edge

Distance between neighboring cells is normalized to unit distance so that only the orientation of each edge matters. The gradient is then the difference in expression of each embedding dimension between the two endpoints of the edge.

Usage

estimate_field_edges_cpp(coords, embeddings, from_pt, to_pt)

Arguments

coords

A N x 2 matrix of cell coordinates.

embeddings

A N x D matrix of cell embeddings.

from_pt, to_pt

A pair of E-length vectors indicating the start and end points of each edge (0-indexed).

Value

A 2 x D x E array in column-major ordering containing the spatial gradient in expression for each of D embedding dimensions at every edge.