function indicator = checkstop(old,new,dt)
% indicate whether we should performance further iteraions or stop

% Copyright (c) 2009, 
% Yue Wu @ ECE Department, Tufts University
% All Rights Reserved  

layer = size(new,3);

for i = 1:layer
    old_{i} = old(:,:,i);
    new_{i} = new(:,:,i);
end

if layer
    ind = find(abs(new)<=.5);
    M = length(ind);
    Q = sum(abs(new(ind)-old(ind)))./M;
    if Q<=dt*.18^2
        indicator = 1;
    else
        indicator = 0;
    end
else
    ind1 = find(abs(old_{1})<1);
    ind2 = find(abs(old_{2})<1);
    M1 = length(ind1);
    M2 = length(ind2);
    Q1 = sum(abs(new_{1}(ind1)-old_{1}(ind1)))./M1;
    Q2 = sum(abs(new_{2}(ind2)-old_{2}(ind2)))./M2;
    if Q1<=dt*.18^2 && Q2<=dt*.18^2
        indicator = 1;
    else
        indicator = 0;
    end
end
return