function A = dirneu1d(n)
% function A = dirneu1d(n)
%

d = ones(n,1);
A = spdiags([-1*d 2*d -1*d], [-1 0 1], n, n);
A(n,n)=1;


function A = dirneu2(n,a,b)
% function A = dirneu2(n,a,b)
%

h = 1/(n-1);
d = ones(n,1);
A = spdiags([-1*d 2*d -1*d], [-1 0 1], n, n);
A(1,1) = h*a-b; A(1,2) = b; 
A(n,n)=1;