Compute rebinning weight matrix — rebin

Returns an M x N matrix W where W[i,j] is the fraction of source bin j that falls within destination bin i. Applying W %*% src_counts gives the same result as rebin_counts(src_edges, src_counts, dest_edges).

Usage

rebin_matrix(src_edges, dest_edges)

Arguments

src_edges: numeric vector (length N+1). Source bin boundaries. Must be monotonically increasing.
dest_edges: numeric vector (length M+1). Destination bin boundaries. Must be monotonically increasing.

Value

numeric matrix (M x N) of overlap fractions.

Details

Precomputing W is efficient when the same bin edges are reused for many observations (e.g., all weight composition observations share the same length-to-weight bin mapping).

Examples

src_edges  <- 0:4
dest_edges <- c(0, 2, 4)
W <- rebin_matrix(src_edges, dest_edges)
# W %*% c(10, 20, 15, 5) gives the coarsened counts