You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: nufft_best_gauss.m
    path of file: ./repos/CS_MoCo_LAB/reconstruction/matlab/CS_LAB_matlab/utils/utils_NUFFT
    
    the code of the file until where you have to start completion:  function [sig, kernel, kernel_ft] = nufft_best_gauss(J, K_N, sn_type)
%function [sig, kernel, kernel_ft] = nufft_best_gauss(J, K_N, sn_type)
%	Return "sigma" of best (truncated) gaussian for NUFFT
%	with previously numerically-optimized width
    
function [sig, kernel, kernel_ft] = nufft_best_gauss(J, K_N, sn_type)
%function [sig, kernel, kernel_ft] = nufft_best_gauss(J, K_N, sn_type)
%	Return "sigma" of best (truncated) gaussian for NUFFT
%	with previously numerically-optimized width
%	in
%		K_N		K/N
%		J		# of neighbors used per frequency location
%		sn_type		'zn' or 'ft' (latter recommend