(Internal) Helper function to create an InfinitySparseMatrix from a set of scores, a treatment indicator, and a caliper width.
scoreCaliper(x, z, caliper)The scores, a vector indicating the 1-D location of each unit.
The treatment assignment vector (same length as x)
The width of the caliper with respect to the scores
x.
An InfinitySparseMatrix object, suitable to be
passed to match_on as an within argument.