m=15;                                  % Laplace problem size
A=Laplacian(m,2);                            
[L,U]=lu(A); spy(L)                    % LU for the Laplace problem
[Lt0,Ut0]=ilu(A); spy(Lt0)             % ILU0 for the Laplace problem
setup.type='ilutp'; 
setup.droptol=0.01;                    % ILU(0.01) for the Laplace problem
[Lt001,Ut001]=ilu(A,setup); spy(Lt001)
setup.droptol=0.002;                   % ILU(0.002) for the Laplace problem
[Lt002,Ut002]=ilu(A,setup); spy(Lt002)
