% @(#) 6.728 Utility code -- Matlab Code
% @(#) Computes the 1 through nth Hermite polynomials and stores them
% @(#) in a matrix. This code uses looping convolutions - speed is good.


function s = hermall(hsize);
hm=zeros(hsize+1,hsize+1);
	hp2 =[1];
        hm(1,:) = [ zeros(1,hsize) 1];
	hp1 =[2 0];
        hm(2,:) = [ zeros(1,hsize-1) 2 0];

for n=2:(hsize);
     	h=conv([2 0],hp1)-[0 0 2*(n-1)*hp2];
        hp2 = hp1;
        hp1 = h;
        hm(n+1,:) = [ zeros(1,hsize-n) h] ;
end

clear hp1
clear hp2
clear h
s=sparse(hm);
clear hm