%
% test of two grid code: test3.m
%
global sigma 
sigma=0;
lmax=10;
itmax=5;
convhist=zeros(itmax,lmax-4);
for l=5:lmax
	nl=2^l; nt=nl+1; x=0:nl; x=x'/nl; v=sin(6*pi*x)+sin(17*pi*x);
	f=zeros(nt,1);
	for it = 1:itmax
		vt=twogrid(v,f,2,2);
		convhist(it,l-4)=norm(vt,inf)/norm(v,inf);
		v=vt;
	end
end
convhist