IDX = VL_BINSEARCH(B, X) maps the elements of X to the bins defined by B. B is a non-decreasing vector of M real numbers defining bins [-inf, B(1)), [B(1), B(2)), ... [B(M) +inf] (note that the last bin contains +inf). The bins are numbered from 0 to M. X is a real (plain) array and IDX is an array with the same dimensions of X, specifying the bin correpsonding to each element of X.
If B(1) = -inf the bin number 0 is removed and the bin number 1 is [-inf B(2)). If B(M) = +inf, the last bin M is the singleton +inf.