D.G.A. Smith's C library for fast computation of a Gaussian and its derivative on a grid
copied from cf-staging / gau2gridA collocation code for computing gaussians on a grid of the form: out_Lp = x^l y^m z^n \sum_i coeff_i e^(exponent_i * (|center - p|)^2) , where the returned matrix dimension are the angular momentum (L) by number of requested points (p).
