function good = gdiam(n,A0,xx,mask)
global locm
locm = mask;

m = size(A0,1);
global A C 
C = zeros(m,1); C(2)=1;

A = A0;

h = strict(A);
k1 = sum(h.^(0:(n-1)));
k2 = h^(n-1);

y = 0;

GG = [];
for k=1:m
  g = gamma(n,xx{k});
  %y = y + gamma(n,xx{k});
  GG = [GG;g'];
end


s1 = abs(sum(max(GG)));
s2 = abs(sum(min(GG)));
y = max(s1,s2);


good =  (y <= k1 + k2*diam(xx) + 1e-10);

keyboard


return


function r = F(x)
global locm
r = applymask(locm,x);
return

function r = applymask(mask,x)
n = length(x);
r = 0;
for i=1:n
  r = r + ismember(x(i),mask{i});
end
return


function r = phin(n,x)
global locm
r = applymask(locm(n:end),x);
return


function p = p_0(x)
global C
p = C(x);
return

function p = p_n(i,j,n)
% primitive cond prob
global A
if i
  p = A(i,j,n);
else
  p = 1;
end
return

function y=mu(n,k)
global locm
mm = locm{n};
y = ismember(k,mm);
return

function [Ak,Bk] = getAB(n)
global A
[m,m,t] = size(A);

Ak = zeros(m,1);
Bk = zeros(m,1);

if n==2
  for k=1:m
    Ak(k) = p_n(k,1,n-1)*mu(1,1) - p_n(k,2,n-1)*mu(1,2) + mu(2,k)*( p_n(k,1,n-1) - p_n(k,2,n-1) );
    Bk(k) = p_n(k,1,n-1) - p_n(k,2,n-1);
  end
else
  [Ak0,Bk0] = getAB(n-1);
  pkk = A(:,:,n-1);
  mk = zeros(m,1);
  for k=1:m
    mk(k) = mu(n,k);
  end
  
  Bk = pkk * Bk0;
  Ak = pkk * Ak0 + Bk.*mk;  
  
  %for k=1:m
  %  Ak(k) = 0;
  %  %Bk(k) = 0;
  %  for k1=1:m
  %    %Ak(k) = Ak(k) + p_n(k,k1,n-1)*(Ak0(k1)+Bk0(k1)*mu(n,k)); %works
  %    Ak(k) = Ak(k) + p_n(k,k1,n-1)*Ak0(k1) +  p_n(k,k1,n-1)*Bk0(k1)*mk(k);
  %    %Bk(k) = Bk(k) + p_n(k,k1,n-1)*Bk0(k1);
  %  end
  %end
end
return


function gam = gamma(n,x)
global locm
[Ak,Bk] = getAB(n);
gam = Ak + Bk*applymask(locm(n+1:end),x);
return