function alf = alphamix(P,m,n)
A = zeros(n-1);
for j=1:n-1
  P1j = getmargX(P,m,n,1:j);
  for k=1:n-j
    Pjk = getmargX(P,m,n,j+k:n);
    
    P1jkn = getmargX(P,m,n,[1:j,j+k:n]);
    dd = abs(tensprod1(P1j,Pjk)-P1jkn);
    
    A(j,k) = sum(dd)/2;
  end
end
alf = max(A);
return

function i=c2i(c,m,n)
dims = repmat(m,[1 n]);
i = coord2ind(c,dims);
return

function c=i2c(i,m,n)
dims = repmat(m,[1 n]);
c = ind2coord(i,dims);
return