function k = kerbiwt(xg,h) 
% KERBIWT, evaluates the BiWeight KERnel 
%     at a grid of x's, xg (matrix or vector),
%     for the bandwidth h
%     For use in NonParametric Regression MOVies

%    Copyright (c) J. S. Marron and D. Ruppert, 1997

k = (1 - (xg / h).^2) ;
k = k .* (k > 0) ;
k = (15/(16 * h)) * k.^2 ;




